No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Does Postoperative Glenoid Retroversion Affect the 2-Year Clinical and Radiographic Outcomes for Total Shoulder Arthroplasty?
Abstract
Background:
While glenoid retroversion and posterior humeral head decentering are common preoperative features of severely arthritic glenohumeral joints, the relationship of postoperative glenoid component retroversion to the clinical results of total shoulder arthroplasty (TSA) is unclear. Studies have indicated concern for inferior outcomes when glenoid components are inserted in 15° or more retroversion.
Questions/purposes:
In a population of patients undergoing TSA in whom no specific efforts were made to change the version of the glenoid, we asked whether at 2 years after surgery patients having glenoid components implanted in 15° or greater retroversion had (1) less improvement in the Simple Shoulder Test (SST) score and lower SST scores; (2) higher percentages of central peg lucency, higher Lazarus radiolucency grades, higher mean percentages of posterior decentering, and more frequent central peg perforation; or (3) a greater percentage having revision for glenoid component failure compared with patients with glenoid components implanted in less than 15° retroversion.
Methods:
Between August 24, 2010 and October 22, 2013, information for 201 TSAs performed using a standard all-polyethylene pegged glenoid component were entered in a longitudinally maintained database. Of these, 171 (85%) patients had SST scores preoperatively and between 18 and 36 months after surgery. Ninety-three of these patients had preoperative radiographs in the database and immediate postoperative radiographs and postoperative radiographs taken in a range of 18 to 30 months after surgery. Twenty-two patients had radiographs that were inadequate for measurement at the preoperative, immediate postoperative, or latest followup time so that they could not be included. These excluded patients did not have substantially different mean age, sex distribution, time of followup, distribution of diagnoses, American Society of Anesthesiologists class, alcohol use, smoking history, BMI, or history of prior surgery from those included in the analysis. Preoperative retroversion measurements were available for 11 (11 shoulders) of the 22 excluded patients. For these 11 shoulders, the mean (± SD) retroversion was 15.8° ± 14.6°, five had less than 15°, and six had more than 15° retroversion. We analyzed the remaining 71 TSAs, comparing the 21 in which the glenoid component was implanted in 15° or greater retroversion (mean ± SD, 20.7° ± 5.3°) with the 50 in which it was implanted in less than 15° retroversion (mean ± SD, 5.7° ± 6.9°). At the 2-year followup (mean ± SD, 2.5 ± 0.6 years; range, 18-36 months), we determined the latest SST scores and preoperative to postoperative improvement in SST scores, the percentage of maximal possible improvement, glenoid component radiolucencies, posterior humeral head decentering, and percentages of shoulders having revision surgery. Radiographic measurements were performed by three orthopaedic surgeons who were not involved in the care of these patients. The primary study endpoint was the preoperative to postoperative improvement in the SST score.
Results:
With the numbers available, the mean (± SD) improvement in the SST (6.7 ± 3.6; from 2.6 ± 2.6 to 9.3 ± 2.9) for the retroverted group was not inferior to that for the nonretroverted group (5.8 ± 3.6; from 3.7 ± 2.5 to 9.4 ± 3.0). The mean difference in improvement between the two groups was 0.9 (95% CI, - 2.5 to 0.7; p = 0.412). The percent of maximal possible improvement (%MPI) for the retroverted glenoids (70% ± 31%) was not inferior to that for the nonretroverted glenoids (67% ± 44%). The mean difference between the two groups was 3% (95% CI, - 18% to 12%; p = 0.857). The 2-year SST scores for the retroverted (9.3 ± 2.9) and the nonretroverted glenoid groups (9.4 ± 3.0) were similar (mean difference, 0.2; 95% CI, - 1.1 to 1.4; p = 0.697). No patient in either group reported symptoms of subluxation or dislocation. With the numbers available, the radiographic results for the retroverted glenoid group were similar to those for the nonretroverted group with respect to central peg lucency (four of 21 [19%] versus six of 50 [12%]; p = 0.436; odds ratio, 1.7; 95% CI, 0.4-6.9), average Lazarus radiolucency scores (0.5 versus 0.7, Mann-Whitney U p value = 0.873; Wilcoxon rank sum test W = 512, p value = 0.836), and the mean percentage of posterior humeral head decentering (3.4% ± 5.5% versus 1.6% ± 6.0%; p = 0.223). With the numbers available, the percentage of patients with retroverted glenoids undergoing revision (0 of 21 [0%]) was not inferior to the percentage of those with nonretroverted glenoids (three of 50; [6%]; p = 0.251).
Conclusion:
In this small series of TSAs, postoperative glenoid retroversion was not associated with inferior clinical results at 2 years after surgery. This suggests that it may be possible to effectively manage arthritic glenohumeral joints without specific attempts to modify glenoid version. Larger, longer-term studies will be necessary to further explore the results of this approach.
Level of evidence:
Level III, therapeutic study.
... One of the commonly used glenoid designs is an allpolyethylene component that is fixed to bone with cemented peripheral pegs and an uncemented fluted central peg. The outcomes for patients receiving this glenoid component have been the subject of recent reports by surgeons from different countries [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]; however, the patients in these articles have not been analyzed together as a cohort of individuals. We contacted the authors of these publications requesting their most recent data on each patient having a total shoulder using this glenoid design so that we could perform a "by patient" analysis in which the clinical outcome for each patient was weighted individually. ...
... Second, the maximal possible improvement for each patient was determined as the difference between the maximal possible value for the outcome scale and the patient's preoperative score. The amount of improvement achieved by each patient was then divided by the maximal possible improvement to obtain the percent of maximal possible improvement (%MPI)-clinically significant improvement has been defined as improvement of at least 30% of the maximal possible improvement [12,27,[38][39][40][41][42]. ...
... An interesting finding in this analysis was that with this basic glenoid component design, type B glenoids and glenoids with more than 15°of retroversion did not have outcomes that were inferior to those with less severe glenoid pathoanatomy. While special glenoid components have been designed for the type B retroverted glenoid [26,45,46], our study and other recent publications [27,39,47,48] point out that the role for these special components has yet to be clarified. ...
... This reflects preselected characteristics of the pathoanatomy of these cohorts, as severely retroverted or dysplastic glenoids were not selected and there was no significant correction during the procedure. 38 The clinical significance of both of these reproducible radiographic measurements is not well established, 7,38,50 although there was no difference between the cohorts. ...
... This reflects preselected characteristics of the pathoanatomy of these cohorts, as severely retroverted or dysplastic glenoids were not selected and there was no significant correction during the procedure. 38 The clinical significance of both of these reproducible radiographic measurements is not well established, 7,38,50 although there was no difference between the cohorts. ...
... 20 Additionally, this procedure may be inadvisable for patients with high degrees of retroversion if concentric reaming is likely to remove valuable bone stock. 38,52 Ultimately, a minority of patients will be candidates for the ream and run procedure. This further corroborates the notion of the 4 Ps regarding operative management emphasized by Matsen 23 : right patient, right procedure, right physician, and right problem. ...
The purpose of this study was to establish functional outcomes regarding return to sport activity for patients receiving anatomical total shoulder arthroplasty (aTSA) vs the ream and run procedure (hemi RR). Patients who underwent hemi RR and who underwent aTSA with a polyethylene glenoid component for end-stage glenohumeral arthritis were retrospectively identified from 2000 to 2014. Patients were matched regarding age, body mass index, sex, and hand dominance. Patients were surveyed to determine their level of sport and satisfaction after surgery. At a mean follow-up of 69.1±24.8 months, a total of 26 hemi RR and 30 aTSA patients met inclusion/exclusion criteria. Mean±SD age at the time of surgery was 53.0±8.5 years. There was no statistical difference between the two cohorts regarding patients who reported no postoperative problems (69.2% vs 76.7%, P=.529), reoperation (11.5% vs 6.7%, P=.522), return to overall sport (94.4% vs 86.4%, P=.395), return to high-demand upper-extremity sport (92.3% vs 81.3%, P=.390), and return to same or better level of intensity sport (83.3% vs 72.7%, P=.424). Patients returned to sport at a mean of 7.5±5.7 months and 6.2±3.6 months in the hemi RR and aTSA cohorts, respectively (P=.485). Radiographic measurements of medialization (mean, −2.4±5.0 vs −2.2±5.7; P=.913) and postoperative decentering (mean, 3.6%±2.6% vs 4.3%±3.3%; P=.795) were equivalent for the two cohorts. Hemi RR was found to have high and equivalent rates of sporting outcomes, clinical outcomes, and radiographic outcomes compared with aTSA. As appropriately indicated patients are counseled for surgery, realistic expectations regarding sports should be discussed. [Orthopedics. 2019; 42(5):276–284.]
... Twenty-six (42.6%) studies assessed the relationship between preoperative glenoid version and at least one patient reported outcome, 2,17,[19][20][21]26,34,39,40,47,49,50,54,57,58,60,62,64,66,67,78,85,91 of which 6 (23.1%) found at least one significant relationship. Four (66.7%) of these significant findings included a correlation between increased preoperative glenoid retroversion and worse postoperative scores on at least one patientreported outcome measure. ...
... Twenty-nine (47.5%) studies assessed the relationship between preoperative glenoid version and at least one radiologic outcome. [2][3][4]13,[19][20][21][22]26,30,[39][40][41]44,47,49,54,55,59,60,74,78,85,91,93,96,98,99,103 Among these, 10 studies (34.5%) found at least one significant relationship. Five (50%) of these significant findings included the association between increased preoperative retroversion (or the magnitude of version correction) and increased radiographic loosening, while 3 (30%) of the significant findings related to the association between residually increased postoperative glenoid retroversion and increased scapulohumeral subluxation. ...
... It is therefore critical to carefully examine the amount of bone loss and version correction required before reaming so that, if sufficient bone stock is available, retroversion correction can be favored. However, Service et al. [45] in 2017 presented contrasting data by comparing the outcomes of glenoid components that were implanted at < 15° or > 15° of final retroversion. The results showed that, apart from increased peg perforation in the more retroverted group, no significant differences in clinical or radiographic outcomes were reported [45]. ...
... However, Service et al. [45] in 2017 presented contrasting data by comparing the outcomes of glenoid components that were implanted at < 15° or > 15° of final retroversion. The results showed that, apart from increased peg perforation in the more retroverted group, no significant differences in clinical or radiographic outcomes were reported [45]. Orvets et al. [46], who recently conducted a clinical study involving aTSA corrective reaming for patients with B2 glenoids, found that treatment of shoulders with an average of 18° of preoperative retroversion and 67% humeral head posterior subluxation resulted in favorable clinical outcomes. ...
Biconcave (B2) glenoids, characterized by significant posterior glenoid bone loss and a biconcave wear pattern, are a challenging pathology in shoulder surgery. Significant bone defects present in B2 glenoids increases the risk of complications and rates of failure for operative patients with glenohumeral osteoarthritis. Diagnosing this entity is of pivotal importance, and can be accomplished with imaging and a comprehensive clinical investigation. There are no clear-cut guidelines for management, but options include hemiarthroplasty, anatomic total shoulder arthroplasty, and reverse shoulder arthroplasty. In recent years, modern techniques such as corrective reaming, bone grafts, and the use of augmented components have improved patient outcomes. Educating prospective patients is essential for reaching a shared management decision, setting appropriate expectations, and optimizing prognostic outcomes.
... Not all centres agree that retroversion need be corrected with any technique. A contrarian view from Service et al. suggests that correction of retroversion is unnecessary [99]. Their work showed that simple reaming of the glenoid without version correction provided reasonable clinical results without decentering of the humeral head at mid-term follow-up [99]. ...
... A contrarian view from Service et al. suggests that correction of retroversion is unnecessary [99]. Their work showed that simple reaming of the glenoid without version correction provided reasonable clinical results without decentering of the humeral head at mid-term follow-up [99]. This work would need to be replicated by other centres prior to widespread adoption. ...
Anatomical total shoulder arthroplasty (aTSA) in its modern form where it reproduces the normal shoulder has been utilized clinically for more than half a century. As the technology and the designs have changed to recreate the humeral and glenoid sides of the joint, the sophistication of design has resulted in the growing number of cases annually worldwide. This increase is due in part to the increasing number of indications that the prosthesis can treat with successful results. On the humeral side there have been design changes to better reflect the proximal humeral anatomy, and humeral stems are increasingly placed safely without cement. Platform systems which allow conversion of a failed arthroplasty to a reverse configuration without stem extraction is another design change. Similarly, there has been increasing utilization of short stem and stemless humeral components. Extensive experience with shorter stem and stemless devices however has yet to demonstrate the purported advantages of these devices, as recent studies have demonstrated equivalent blood loss, fracture rates, operative times, and outcome scores. Easier revision with these shorter stems remains to be definitively established, with only one study comparing ease of revision between stem types. On the glenoid side, hybrid cementless glenoids, inlay glenoids, cementless all-polyethylene glenoids, and augmented glenoids have all been investigated, however the indications for these devices remain unclear. Lastly, innovative surgical approaches to implanting shoulder arthroplasty and the use of patient specific guides and computerized planning, while interesting concepts, still await validation before they are utilized on a widespread basis. While reverse shoulder arthroplasty has been increasingly used to reconstruct the arthritic shoulder, anatomic glenohumeral replacement maintains a significant role in the armamentarium of the shoulder surgeon.
... Gunther and Tran 30 used an inset glenoid component placed in deformed arthritic glenoid bone without the use of advanced imaging or instrumentation and found long-term efficacy and safety of shoulder arthroplasty. In a series reported on by Service et al. 31 in which no 3D imaging or PSI was used, the authors found that postoperative glenoid retroversion was not associated with inferior clinical results at 2 years after TSA. They concluded that it was possible to effectively manage arthritic glenohumeral joints without specific attempts to modify glenoid version either by asymmetric reaming or by using augmented glenoid components. ...
Background
Ongoing innovation leads to a continuous influx of new technologies related to shoulder arthroplasty. These are made available to surgeons and marketed to both health-care providers and patients with the hope of improving outcomes. We sought to evaluate how preoperative planning technologies for shoulder arthroplasty affect outcomes.
Methods
This was a retrospective cohort study conducted using data from an integrated health-care system’s shoulder arthroplasty registry. Adult patients who underwent primary elective anatomic or reverse total shoulder arthroplasty (2015 to 2020) were identified. Preoperative planning technologies were identified as (1) a computed tomography (CT) scan and (2) patient-specific instrumentation (PSI). Multivariable Cox regression and logistic regression were used to compare the risk of aseptic revision and 90-day adverse events, respectively, between procedures for which technologies were and were not used.
Results
The study sample included 8,117 procedures (in 7,372 patients) with an average follow-up of 2.9 years (maximum, 6 years). No reduction in the risk of aseptic revision was observed for patients having either preoperative CT scans (hazard ratio [HR] = 1.22; 95% confidence interval [CI] = 0.87 to 1.72) or PSI (HR = 1.44; 95% CI = 0.71 to 2.92). Patients having CT scans had a lower likelihood of 90-day emergency department visits (odds ratio [OR] = 0.84; 95% CI = 0.73 to 0.97) but a higher likelihood of 90-day venous thromboembolic events (OR = 1.79; 95% CI = 1.18 to 2.74). Patients with PSI use had a higher likelihood of 90-day deep infection (OR = 7.74; 95% CI = 1.11 to 53.94).
Conclusions
We found no reduction in the risk of aseptic revision with the use of these technologies. Patients having CT scans and PSI use had a higher likelihood of venous thromboembolism and deep infection, respectively. Ongoing research with extended follow-up is being conducted to further examine the effects of these technologies on patient outcomes.
Level of Evidence
Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.
... In comparison to the wide variation seen with MCID values, it 197is unknown whether the MCI-%MPI will also vary substantially across patient populations. At 198 present, studies reporting on the %MPI in shoulder arthroplasty patients do not utilize score-199 specific thresholds.10,16,23 Further studies are needed to determine whether the MCI-%MPI will be 200 population-dependent similar to MCID values or if it will prove to be more robust. ...
Introduction:
Changes in pre- to postoperative outcome scores are often used to quantify success after anatomic total shoulder arthroplasty (aTSA). However, ceiling effects associated with many outcome scores limit the ability to differentiate success among high-functioning patients. The percent maximal possible improvement (%MPI) was introduced to better stratify patient success; however, it is unclear if the 30% threshold first proposed correlates with perceived patient success across all outcome scores. The purpose of this study was to compare the proportion of patients that achieved the minimal clinically important difference (MCID) and %MPI for different outcome scores and to define the %MPI thresholds associated with patient satisfaction following primary aTSA.
Methods:
A retrospective review was performed of an international shoulder arthroplasty database between 2003 and 2020. All primary aTSAs performed using a single implant system with minimum 2-year follow-up were reviewed. Pre- and postoperative outcome scores were evaluated for all patients to calculate improvement. The proportion of patients achieving the MCID and 30% MPI were determined for each outcome score. Thresholds for the minimal clinically important %MPI (MCI-%MPI) were calculated using an anchor-based method for each outcome score and stratified by age and sex.
Results:
1,593 shoulders with a mean follow-up of 59.3 months were included. Outcome scores with known ceiling effects (SST, ASES, UCLA) had higher rates of patients achieving the 30% MPI, but not the previously reported MCID. Inversely, outcome scores without significant ceiling effects (Constant and SAS scores) had higher rates of patients achieving the MCID, but not the 30% MPI. The MCI-%MPI differed among outcome scores and mean values were as follows: 33% for the SST, 24% for the Constant score, 32% for the ASES score, 38% for the UCLA score, 30% for the SPADI score, and 33% for the SAS score. The MCI-%MPI increased with greater age (P < .003) and females had thresholds greater than or equal to males for all scores assessed, meaning that patients with higher thresholds required a greater fraction of the possible improvement for a given score to be satisfied.
Conclusion:
The %MPI offers a simple method to quickly assess improvements across patient outcome scores. However, the %MPI that represents patient improvement after surgery is not uniformly the previously established 30% threshold. Surgeons should utilize score-specific estimates of the MCI-%MPI to gauge success when evaluating patients undergoing primary aTSA.
... Excessive glenoid retroversion has been shown to result in component loosening and clinical failure if not adequately recognized and addressed, though the threshold of retroversion is still debatable. 7,10,11,21,23 Excessive glenoid inclination can result in rotator cuff failure in TSA and can have a significant effect on biomechanics in RSA, potentially compromising outcomes. 11,14,18,24 Though methods have been described to measure glenoid version and inclination on plain radiographs, computed tomography (CT) has been shown to be more accurate, especially with the use of 3-dimensional (3D) reconstruction or reformatting software. ...
Background
Variability exists between total shoulder arthroplasty preoperative planning software (PPS) systems for glenoid angular measurements. The purpose of this study is to locate the region on the glenoid at which inclination and version are measured on the PPS modalities of Blueprint and VIP.
Methods
Preoperative Computed Tomography (CT) scans of 30 consecutive patients undergoing primary arthroplasty were analyzed using two PPS’s (VIP and Blueprint) to independently obtain glenoid version and inclination measurements through their respective protocols. 3D equivalent images were independently analyzed utilizing open-source OsiriX DICOM software by two board certified orthopedic sports medicine surgeons measuring glenoid version and inclination along ten equal intervals of the glenoid from superior to inferior and anterior to posterior, respectively. Manual version and inclination measurements were compared to both the VIP and the Blueprint measurements and variances were analyzed by calculating Root Mean Square Error (RMSE). The closest interval (1, 2, 3, 4, 5, 6, 7, 8, 9, 10) to the VIP and Blueprint measurement was identified for both version and inclination to determine the region of the glenoid both software programs obtained their measurements.
Results
Mean glenoid retroversion manually measured using OsiriX was 13.5° compared with 15.1° recorded by Blueprint (p=0.516) and 12.2° by VIP (p=0.621). Mean inclination using OsiriX was 5.5°, compared with 7.1° (p=0.314) and 9.0° (p=0.024) recorded by Blueprint and VIP, respectively. RMSE for version between Osirix and VIP was 4.65°, Osirix and Blueprint was 4.44°, and VIP and Blueprint was 4.45°. RMSE for inclination between Osirix and VIP was 6.43°, Osirix and Blueprint was 5.25°, and VIP and Blueprint was 5.13°. For version, VIP measurements most frequently aligned with the inferior quadrant of the glenoid (n=13) with a median interval 7 while Blueprint aligned with the superior quadrant of the glenoid (n=13) with median interval 4. Inclination measurements aligned with the posterior quadrant of the glenoid for both VIP (n = 19) and Blueprint (n = 15) with median interval 8.
Conclusion
PPS systems for shoulder arthroplasty vary in the region of the glenoid for which version and inclination are measured, which may affect the absolute values generated. Location of version measurement was different among the two commercial software programs with VIP corresponding closest to the most inferior region of the glenoid while Blueprint the most superior. Further research should assist in determining the version and inclination variations among commercial planning software.
... 12,48,50 aTSA with an on-lay component, leaving the glenoid in retroversion, has also been described on a limited basis, but the only retrospective review available did not have preoperative CT scans and only 21 of 71 patients included were left in retroversion. 42 Concerns about aTSA implanted in retroversion stem from the fact that finite element analyses show increased posterior stresses and decreased predicted cyclic fatigue tolerance. 11 Clinically, this can manifest as increased osteolysis around the central peg, thought to be an early marker for glenoid failure 39 in standard aTSA implants placed in greater than 15 of retroversion. ...
Background
Glenoid bone loss in anatomic total shoulder arthroplasty (aTSA) remains a controversial and challenging clinical problem. Previous studies have shown high rates of glenoid loosening for aTSA in shoulders with retroversion, posterior bone loss, and posterior humeral head subluxation. This study is the first to present minimum two-year follow-up data of an all-polyethylene, biconvex augmented anatomic glenoid component for correction of glenoid retroversion and posterior humeral head subluxation.
Methods
This study is a multi-center, retrospective review of prospectively collected data on consecutive patients from 7 global clinical sites. All patients underwent aTSA using the biconvex posterior augmented glenoid (PAG). Inclusion criteria were: Preoperative computed tomography (CT) scan, minimum 2-years since surgery, pre and minimum 2-year postoperative range of motion exam and PROMs. Glenoid classification, glenoid retroversion, and posterior humeral head subluxation were measured from preoperative CT and XR, and postoperative XR. Statistical comparisons between pre- and postoperative values were performed with a paired t-test.
Results
86 of 110 consecutive patients during the study period (78% follow-up) met the inclusion criteria and were included in our analysis. Mean follow-up was 35 ± 10 months with a mean age of 68 ± 8 (range 48 to 85) years. Range of motion statistically improved in all planes from pre- to postop. VAS improved from 5.2 preop to 0.7 postop, SANE from 43.2 to 89.5, Constant from 41.8 to 76.9, and ASES from 49.8 to 86.7 (all p < 0.0001). Mean glenoid retroversion improved from 19.3° to 7.4° (p <0.0001). Posterior subluxation improved from 69.1% to 53.5% and posterior decentering improved from 5.8% to -3.0% (p<0.0001). There was one patient with both a prosthetic joint infection and radiographic glenoid loosening that required revision. 79/86 had a Lazarus score of 0 (no radiolucency seen about peg or keel) at final follow-up.
Conclusions
This study shows that at minimum 2-year follow-up, a posterior-augmented all-polyethylene glenoid can correct glenoid retroversion and posterior humeral head subluxation. Clinically, there was significant improvement in both ROM and PROMs.
... Gregory et al. confirmed that an inferiorly inclined glenoid component was associated with increased radiolucent lines [1]. Other research has shown no association between glenoid component version and clinical outcome scores [8,9]. For these reasons, it is important to examine and quantify the glenoid component position over time, and further, to determine whether glenoid component position impacts clinical or patient-reported outcomes. ...
Background:
Malpositioning of the glenoid component in total shoulder arthroplasty (TSA) remains the primary source of loosening. The purpose of this study is firstly, to quantify postoperative glenoid component position in patients having a TSA and secondly, to explore whether glenoid component radiolucency is associated with glenoid position, clinical outcomes and patient-reported measures in the short-term (two year) follow-up period.
Methods:
This study was a sub-study of a larger clinical trial that included patients who underwent a TSA and who were randomized into two different glenoid types with a minimum two-year follow-up period. Post-operative radiographic assessments (six weeks and two years) were used to measure glenoid component position (version, inclination, offset) and humeral head centering anterior-posterior (AP) and superior-inferior (SI), and to assess glenoid component radiolucent scoring (modified Lazarus). Pre-operative X-rays were used to measure glenoid version, inclination and Walch classification. Patient-reported measures (PROMs) included the EQ-5D health slider and the Western Ontario Osteoarthritis (WOOS) and American Shoulder and Elbow Surgeons (ASES) score and were captured at baseline and two years postoperative. Clinical outcomes including range of motion and complications were also documented. Statistical analysis included t-tests and regression modeling.
Results:
Ninety-one patients with an average age of 69.9 ± 6.2 years were included in this study. Glenoid component position improved significantly in version (-19.4 ± 8.6° to -17.7 ± 8.5°; p < 0.045) and inclination (11.5 ± 7.1° to 5.9 ± 6.3°; p < 0.00001) from preoperative to six weeks postoperative. Glenoid component offset in SI and humeral head centering in AP remained unchanged throughout the follow-up. Radiolucency (Lazarus classification) was recorded in 21 cases (17.3%) with a Lazarus score of 1 (15 cases) and 2 (6 cases). The EQ-5D health slider, WOOS and ASES, and ROM confirmed continuous improvements from the preoperative scores to the two-year follow-up (p < 0.05). Regression models showed no correlation between glenoid component radiolucency at two years and the postoperative week six glenoid component position; however, female gender was a significant variable.
Conclusion:
Glenoid component changes from its original native glenoid were observed following TSA. Glenoid inclination was improved more than version from baseline, and the humeral head remained well-centered in AP and SI at two years. Radiolucency of the glenoid at two years is not negatively associated with PROMs or component position; however, female gender was identified as a significant predictor and warrants further investigation. Complications are not associated with glenoid position or radiolucency, but longer-term follow-up is required.
... The implications of retroversion during glenoid component implantation are controversial. In biomechanical studies, glenoid component placement in >15°of retroversion significantly decreases GH contact area, increases contact pressure, and results in eccentric loading of the glenoid component 76 77 . However, that study was limited by its use of conventional radiographs and short-term follow-up. ...
Rotator cuff imbalance, soft-tissue and capsular repair defects, and improper component sizing, positioning, and orientation can result in a high-stress environment at the periphery of the glenoid component-bone interface.
➢ The optimal position and orientation of the glenoid for a given individual is currently unknown.
➢ There have been advancements in glenoid design, with the advent of contemporary metal-backed and hybrid components, but their long-term efficacy has not been proven. Inset glenoid components have shown promising short- and mid-term results.
➢ The augmented glenoid, which has shown satisfactory short-term results in the setting of posterior glenoid loss, is a potential option for glenoid bone loss that is too severe for eccentric reaming. It may be technically easier than bone-grafting, does not require union, and is not at risk of collapse or bone graft resorption.
➢ Advances in surgical technique, including patient-specific instrumentation, may provide additional accuracy, especially in dysplastic and eccentrically worn glenoids; however, evidence for clinical benefit is still lacking.
... Glenoid retroversion was measured on the axillary lateral as previously described by Service et al. as the angle between the anterior-posterior glenoid face and the line perpendicular to the axis of the scapula ( Figure 1). 12 Glenoid retroversion was measured independently by 2 orthopedic surgeons (ECC and WX). The intraclass correlation coefficients demonstrated good reliability between reviewers for both preoperative retroversion (ICC ¼ 0.86; 95% confidence interval ¼ 0.81-0.89) ...
Background:
There are limited data on the effect of glenoid retroversion in clinical outcomes following reverse total shoulder arthroplasty (RTSA). The purpose of this study was to evaluate if surgical correction of retroversion affects outcomes following RTSA.
Methods:
An institutional database was utilized to identify 177 patients (mean age: 68.2 ± 10.1 years) with minimum 2-year follow-up after primary RTSA. Glenoid version was measured on preoperative and postoperative radiographs. American Shoulder and Elbow Surgeons (ASES) scores and range of motion were collected before and after RTSA. Change in retroversion was determined by comparing preoperative and postoperative glenoid retroversion on radiographs using paired Wilcoxon signed-rank test. Spearman's rank correlation was used to investigate relationships between ASES scores and glenoid retroversion.
Results:
The mean postoperative ASES composite score (75.5 ± 22.7) was significantly higher than preoperative (36.8 ± 19.2; P < .0001). The mean preoperative glenoid retroversion was 9.1 ± 6.7° compared to 6.5 ± 5.1° postoperatively (P < .0001). There was no correlation between postoperative ASES scores and preoperative retroversion (r = .014, P = .85) or postoperative retroversion (r = -.043, P = .57). There was no statistical relationship between postoperative retroversion and range of motion, though there is a risk of inadequate power given the sample size.
Conclusions:
Patient-reported outcomes and range of motion measurements following RTSA at short-term follow-up appear to be independent of either preoperative or postoperative glenoid retroversion.
... 19 With the introduction of 3dimensional measurements and virtual planning software, there has been a growing appreciation of the challenges in managing glenoid retroversion with anatomic total shoulder arthroplasty (TSA). 13,28 Management of severe retroversion during TSA has remained controversial, as authors have advocated various treatment strategies including partial version correction, 17,24 minimal correction, 21 and use of augmented glenoid components. 4,7,13,24 Although some have advocated correction of glenoid version to within 5 of a plane perpendicular to the plane of the scapula, 13 this can be challenging in cases of severe retroversion in part because of difficulties with exposure, limitations of implant design, the risk of losing subchondral bone support, and the implications of joint medialization. ...
Background:
Ideal management of severe glenoid retroversion during anatomic total shoulder arthroplasty (TSA) remains controversial, as previous reports have suggested that severe retroversion may negatively impact clinical outcomes. The purpose of this study was to evaluate the impact of severe glenoid retroversion on clinical and radiographic TSA outcomes using a standard glenoid component, as well as to compare outcomes among patients with less severe retroversion.
Methods:
A case-control study was performed comparing 40 patients treated with TSA with more than 20° of glenoid retroversion preoperatively (average follow-up, 53 months) vs. a matched cohort of 80 patients with less than 20° of retroversion (average follow-up, 49 months). In all patients, the surgical technique, implant design, and postoperative rehabilitation protocol were identical. Patients were matched based on sex, age, indication, and prosthetic size. Comparisons were made regarding patient-reported outcome measures (PROMs), motion, postoperative radiographic loosening, and the presence of medial calcar resorption.
Results:
Preoperatively, both groups demonstrated similar PROMs and measured motion, except for preoperative Single Assessment Numeric Evaluation scores and American Shoulder and Elbow Surgeons total scores, which were higher for the severe retroversion group (44.4 vs. 31.3 [P = .012] and 34.9 vs. 29.4 [P = .048], respectively). Postoperative PROMs and motion were also similar between the 2 cohorts. No significant differences were observed for postoperative radiographic findings. Medial calcar resorption was identified in 74 patients (61.7%). Calcar resorption and individual resorption grades were not found to differ significantly.
Conclusion:
At midterm follow-up, preoperative severe glenoid retroversion does not appear to influence clinical or radiographic outcomes of TSA using a standard glenoid component.
Background
Glenoid retroversion and humeral head subluxation is a progressive disorder due to abnormal force coupling and increased contact force. In situ placement of anatomic total shoulder arthroplasty (TSA) components in this scenario results in edge loading, progressive subluxation, and early failure. Wedged glenoid components have been demonstrated to improve glenohumeral alignment, but have not been correlated with mid-term clinical outcomes.
Methods
Patients undergoing TSA using a wedged all-polyethylene glenoid component for retroverted glenoid deformity were identified from a prospectively maintained database. Preoperative planning computed tomography was routinely performed and compared to postoperative correction on radiographic evaluation. Evidence of loosening was correlated to prospectively collect clinical outcome using patient-reported outcome measures. A matched group of neutrally aligned glenohumeral joints undergoing anatomic TSA was used to compare improvement in clinical outcomes.
Results
Over a 5-year period, 17 patients with mean age 60 (range 43-81, standard deviation 10.5) were identified with a mean preoperative neoglenoid retroversion of 16.7° (standard deviation 4.5). At a mean follow-up of 43.8 months (range 27-60), no revision surgeries were undertaken. Improvement in the Oxford Shoulder Score was 18 points (P < .0001). The mean improvement was compared to a matched control group demonstrating a comparable magnitude of improvement of 20.4 points.
Conclusion
Wedged polyethylene components for Walch B2-type glenoids in TSA yield acceptable correction of the joint line, excellent clinical outcomes, and survivorship is maintained in the short term. The clinical and radiological outcome demonstrated similar improvement to that seen in A type deformities.
Introduction:
We compare the two-year clinical outcomes of both anatomic and reverse total shoulder arthroplasty (ATSA and RTSA) utilizing intraoperative navigation compared to traditional positioning techniques. We also examine the effect of glenoid implant retroversion on clinical outcomes.
Hypothesis:
In both ATSA and RTSA, computer navigation will be associated with equal or better outcomes with fewer complications. Final glenoid version and degree of correction will not show outcome differences.
Material and methods:
A total of 216 ATSAs and 533 RTSAs were performed using preoperative planning and intraoperative navigation with a minimum of 2-year follow-up. Matched cohorts (2:1) for age, gender and follow-up for cases without intraoperative navigation were compared using all standard shoulder arthroplasty clinical outcome metrics. Two sub-analyses were performed on navigated cases comparing glenoids positioned greater or less than 10° of retroversion and glenoids corrected more or less than 15°.
Results:
For ASTA, no statistical differences found between the navigated and non-navigated cohorts for postoperative complications, glenoid implant loosening or revision rate. No significant differences were seen in any of the ATSA outcome metrics besides higher internal and external rotation in the navigated cohort. For RTSA, the navigated cohort showed an ARR of 1.7% [0,3.4]95 for postoperative complications and 0.7%[0.1,1.2]95 for dislocations. No difference was found in the revision rate, glenoid implant loosening, acromial stress fracture rates, or scapular notching. Navigated RTSA patients demonstrated significant improvements over non-navigated patients in internal rotation, external rotation, maximum lifting weight, the simple shoulder test (SST), Constant, and shoulder arthroplasty smart (SAS) scores. For the navigated sub-cohorts, ATSA cases with a higher degree of final retroversion showed significant improvement in pain, Constant, ASES, SST, UCLA and SPADI. No significant differences were found in the RTSA sub-cohort. Higher degrees of version correction showed improvement in external rotation, SST and Constant scores for ATSA and forward elevation, internal rotation, pain, SST, Constant, ASES, UCLA, SPADI, and SAS scores for RTSA.
Conclusion:
The use of intraoperative navigation shoulder arthroplasty is safe, produces at least equally as good outcomes at two years compared to standard instrumentation without any increased risk of complications. The effect of final implant position above or below 10° of glenoid retroversion and correction more or less than 15° do not negatively impact outcomes.
Background:
The management of Walch B2 glenoid deformities in primary glenohumeral osteoarthritis is frequently debated. Previous literature has shown that the treatment of B2 glenoids with high-side reaming and anatomic total shoulder arthroplasty (TSA) perform well in the short-term, but is associated with an increased glenoid component failure rate in severe deformities. Therefore, many have explored alternative options, including augmented anatomic glenoid components and reverse shoulder arthroplasty. Our goal in this study is to provide mid-term radiographic and clinical outcomes after high-side reaming and anatomic TSA for B2 glenoids.
Methods:
Patients were followed both clinically and radiographically. Preoperative CT scans were used for retrospective analysis of deformity. Both preoperative and postoperative VAS pain, ASES score, and SST scores were collected. Radiographs were analyzed preoperatively and postoperatively for humeral head decentering relative to the glenoid vault, immediate glenoid seating, and final glenoid peg radiolucency.
Results:
Of the original cohort of 59 patients (6 now deceased) reported at a mean radiographic follow-up of 3.4 years, 34 shoulders in 33 patients with B2 glenoids (mean retroversion 18.9°, range 4°-32°) were available for follow-up at a mean of 8.6 years (range 5.5-11.2) after high-side glenoid reaming with anatomic TSA. Three (5.1%) of the original 59 shoulder were revised. At final follow-up, 3 of 30 (10.0%) shoulders had radiographic glenoid component failure, but were unrevised. Glenoid component failure was associated with worse initial glenoid component seating (mean Lazarus score 1.2 vs. 2.0, p=0.002). Glenoid failure was also associated with increased posterior humeral head subluxation at 2-4 year follow-up (mean 5.6% vs 12.6%, p=0.045) and at final follow-up (mean 7.0% vs. 21%, p=0.002). There was no association between glenoid component failure and preoperative retroversion, inclination, or humeral head subluxation (all p>0.05). Glenoid component failure was associated with worse ASES (88 vs. 73) and VAS pain (0.8 vs. 2.1) scores (both p=0.03).
Conclusions:
At a mean of 8.6 years, 88% of shoulders available for follow-up had well-fixed glenoid components. Glenoid component failure was associated with poor initial glenoid component seating, with failed components having an average of 25% of the glenoid component not seated. Preoperative deformity such as glenoid retroversion, inclination, or humeral head subluxation did not predict glenoid component failure. This study supports that initial glenoid component seating and recurrence of posterior humeral head subluxation may be the most important factors for mid-term glenoid component survival in anatomic TSA in patients with B2 glenoids.
The shoulder has become the third most frequently replaced joint, after the hip and knee. Since Neer’s early designs used for fractures, shoulder prostheses have evolved to accommodate the proximal humeral anatomy. However, the most important step in the evolution of shoulder arthroplasty was undoubtedly the introduction of the reverse total shoulder prosthesis. These prosthesis has undergone important changes since its first designs with the aim of minimizing the complications initially observed, especially scapular erosion. Nowadays, we are entering a new stage that has the aim of a better placement of the prostheses, especially of the glenoid component. The objective of this chapter is to address the fundamental concepts in shoulder arthroplasty and the controversial points that arise today within its indications and the different kinds of implants. The chapter is structured in sections organized by pathologies, followed by the most frequent complications found. There is also a section of special relevance nowadays which addresses the treatment of glenoid bone defects.KeywordsTotal shoulder arthroplastyReverse shoulder arthroplastyShort-stem shoulder arthroplasty
Glenoid deformity has an important effect on outcomes and complication rates after shoulder arthroplasty for primary glenohumeral arthritis. The B2/B3 glenoid has particularly been associated with a poorer outcome with shoulder arthroplasty compared with other glenoid types. One of the primary challenges is striking a balance between deformity correction and joint line preservation. Recently, there has been a proliferation of both anatomic and reverse implants that may be used to address glenoid deformity. The purpose of this review was to provide an evidence-based approach for addressing glenoid deformity associated with primary glenohumeral arthritis.
Background
There is concern that excessive glenoid component retroversion leads to altered biomechanics and baseplate failure in reverse shoulder arthroplasty (RSA). However, much of this has been rooted in the total shoulder arthroplasty experience. In the current literature, it is not well-defined whether glenoid baseplate positioning in reverse arthroplasty affects functional outcomes. Our practice has been to preserve glenoid bone stock without aiming for a certain degree of retroversion. We aimed to evaluate the correlation between pre- and postoperative retroversion in a cohort of RSAs as well as determine the effect of glenoid retroversion on functional outcomes, range of motion, and postoperative complications.
Methods
A retrospective review of patients who had an RSA between 2017 and 2019 was performed. Preoperative computed tomography (CT) scans were used to assess preop retroversion, and axillary radiographs were used for postoperative retroversion. Outcome measures included American Shoulder and Elbow Surgeons (ASES) score, Visual Analog Scale (VAS) for pain score, Single Assessment Numerical Evaluation (SANE) score, range of motion, radiographic lucency, and complications.
Results
271 patients were eligible for the study. There was a 76.9 percent 2-year follow-up rate. There were 161 patients who had postoperative retroversion less than or equal to 15 degrees (Group A), and 110 patients who had retroversion greater than 15 degrees (Group B).
There were no significant differences in ASES, VAS, or SANE scores. There were also no significant differences in postoperative range of motion. There was one baseplate failure in each group, and there was one patient in group B with asymptomatic radiographic loosening (baseplate at risk). The mean change in pre- to postoperative retroversion was 1 and 4 degrees in Group A and B, respectively.
Conclusion
There was no significant difference in postoperative functional outcomes, range of motion, or complications between patients who had baseplate retroversion 15 degrees or less versus those who had retroversion greater than 15 degrees.
Background/Hypothesis
There is no consensus to which patient-determined shoulder outcome scores should be considered when analyzing patient outcomes for either clinical or research purposes. Use of multiple patient-determined outcomes may be redundant and cause increased responder burden. To date, the Single Assessment Numeric Evaluation (SANE) has not been widely accepted as a stand-alone shoulder-specific outcome measure. The hypothesis of this study was the SANE will correlate with and be equal or superior in responsiveness to other outcome measures that have been used in a stand-alone fashion in patients undergoing total shoulder arthroplasty [American Shoulder and Elbow Surgeons Score (ASES), Western Ontario Osteoarthritis Score (WOOS), and the Simple Shoulder Test (SST]). In addition, the SANE will be more relevant to each patient compared to the ASES further supporting its use as a stand-alone shoulder-specific outcomes measure.
Methods
A retrospective review of a database of patients undergoing total shoulder arthroplasty was reviewed where the SANE was recorded simultaneously with the ASES, WOOS, and/or SST. Correlations were determined using the Pearson coefficient. Sub-group analysis was performed to determine if correlations differed in 1) preoperative outcome and 2) postoperative outcome determinations. Responsiveness was determined by calculating the standardized response mean (SRM) and the effect size (ES) of both scores. Relevance of the SANE and ASES was examined using 150 consecutive patients to determine the number of questions in each score that were not answered.
Results
Correlation was excellent for the SANE and the ASES (n=1447; r=0.82; p<0.0001), the WOOS (n=1514; r=0.83; p<0.0001), and the SST (n=1095; r=0.81; p<0.0001). Correlation of preoperative scores was moderate and postoperative scores were strong-moderate when comparing the SANE with all three scores. All scores were highly responsive with the SRM of the SANE = 2.2, ASES = 2.3, WOOS = 1.4, and the SST=1.6. The ES of the SANE = 2.9, ASES = 2.9, WOOS = 2.9, and the SST=2.3. 100% of the SANE scores were answered completely compared to 61% (p<0.0001) of the ASES questions.
Conclusion
In patients undergoing total shoulder arthroplasty, the SANE highly correlated with the WOOS, ASES and SST which have been used as stand-alone shoulder-specific outcomes measures. The SANE may provide the same information as the WOOS, ASES, and SST regarding outcome with significant reduction in responder burden. It is logical that the SANE can be utilized as a stand-alone instrument for patients undergoing total shoulder arthroplasty.
Hypothesis
Both clinical outcomes and early rates of failure will not be associated with glenoid retroversion.
Methods
All patients who underwent an anatomic TSA with minimal, non-corrective reaming between 2006 and 2016 with minimum 2-year follow-up were reviewed. Measurements for retroversion, inclination, and posterior subluxation were obtained from MRI or CT. A regression analysis was performed to assess the association between retroversion, inclination and subluxation, and their effect on PROs. Clinical failures and complications were reported.
Results
151 anatomic TSAs (90% follow-up) with a mean follow-up of 4.6 years (range, 2-12 years) were assessed. Mean preoperative retroversion was 15.6° (range, 0.2-42.1), mean posterior subluxation was 15.1% (range, -3.6 to 44.1%), and mean glenoid inclination was 13.9° (range, -11.3 to 44.3). All median outcome scores improved significantly from pre- to postoperatively (p<.001). Median satisfaction was 10/10 (1st quartile=7, 3rd quartile=10). Linear regression analysis found no significant association between retroversion and any postoperative PRO. A total of 5 (3.3%) failures occurred due to glenoid implant loosening (3 patients) and Cutibacterium acnes infection (2 patients) with no association between failure causation and increased retroversion or inclination. No correlation could be found between the Walch classification and postoperative PROs.
Conclusion
Anatomic total shoulder replacement with minimal and non-corrective glenoid reaming demonstrates reliable increases in patient satisfaction and clinical outcomes at a mean of 4.6 years follow-up in patients with up to 40° of native retroversion. Higher values of retroversion were not associated with early deterioration of clinical outcomes, revisions, or failures. Long-term studies are needed to see if survivorship and outcomes hold up over time.
»:
The term "subluxation" means partial separation of the joint surfaces. In the arthritic shoulder, "arthritic glenohumeral subluxation" refers to displacement of the humeral head on the surface of the glenoid.
»:
The degree of arthritic glenohumeral subluxation can be measured using radiography with standardized axillary views or computed tomography (CT).
»:
Shoulders with a type-B1 or B2 glenoid may show more posterior subluxation on an axillary radiograph that is made with the arm in an elevated position than on a CT scan that is made with the arm at the side.
»:
The degree of arthritic glenohumeral subluxation is not closely related to glenoid retroversion.
»:
The position of the humeral head with respect to the plane of the scapula is related to glenoid retroversion and is not a measure of glenohumeral subluxation.
»:
Studies measuring glenohumeral subluxation before and after arthroplasty should clarify its importance to the clinical outcomes of shoulder reconstruction.
Background
Weight lifting after total shoulder arthroplasty (TSA) can place significant stresses on implants that could lead to instability, loosening, and increased wear. A TSA system with nonspherical humeral head resurfacing and inlay glenoid—which improves the biomechanics and thus reduces instability, wear, and potential loosening—may be able to tolerate repetitive loads from weight lifting.
Purpose
To determine clinical and radiographic outcomes after TSA in weight lifters.
Study Design
Case series; Level of evidence, 4.
Methods
We prospectively enrolled 16 weight lifters (mean ± SD age, 57.2 ± 7.8 years; 15 male) undergoing primary anatomic TSA (n = 17 shoulders, 1 staged bilateral) with nonspherical humeral head resurfacing and inlay glenoid replacement for glenohumeral osteoarthritis between February 2015 and February 2019. Exclusion criteria were rotator cuff deficiency, revision TSA, post-traumatic arthritis, and inflammatory arthritis. Outcome measures included the rate of return to weight lifting, results of patient-reported outcome measures (Penn Shoulder Score, Kerlan-Jobe Orthopaedic Clinic, and 12-Item Veterans RAND Health Survey), radiographic outcomes, and complication rate.
Results
Follow-up was obtained on all patients at a mean of 38 months (range, 14-63 months). All patients returned to competitive weight lifting at 15.6 ± 6.9 weeks. Compared to the preoperative weight lifting level, at last follow-up patients reported performance at the following level: lighter weight, 1 (6%); same weight, 8 (50%); heavier weight, 7 (44%). Preoperative eccentric posterior glenoid wear was common (71% Walch B2 classification; 12/17), but posterior humeral subluxation improved at follow-up according to the Walch index (mean, 55.5% preoperative vs 48.5% postoperative; P < .001) and contact point ratio (mean, 63.9% preoperative vs 50.1% postoperative; P < .001). Pre- to postoperative improvements were seen in Penn Shoulder Score (44.3 vs 82.6; P < .001), Kerlan-Jobe Orthopaedic Clinic (50.6 vs 91.1; P < .001), and 12-Item Veterans RAND Health Survey physical component score but not mental component score. No signs of radiographic loosening were detected in follow-up images, nor were there any postoperative instability episodes or revision surgeries.
Conclusion
There were substantial improvements in shoulder function and a high rate of return to weight lifting after TSA with a nonspherical humeral head resurfacing and inlay glenoid component. Radiographically, the humeral head centralized on the glenoid after surgery, and there was no evidence of component loosening at a mean 38-month follow-up.
For practicing shoulder arthroplasty surgeons, it is advisable to consider a breadth of data sources concerning complications and outcomes. Although published series from high-volume centers are the primary source of data, these results may not be generalizable to a wide range of practice settings. National or health system-specific registry and medical device databases are useful adjuncts to assess the changing complication profile of shoulder arthroplasty, as well as to understand the complications specific to certain implants or implant types. To reduce the risk of postoperative complications, surgeons must have a clear understanding of the most common modes of failure.
Hypothesis
The purpose of this study is to evaluate whether the amount of measured posterior bone loss on 2D and 3D imaging of Walch B2 glenoids can reliably predict the plan for an augmented anatomic glenoid component.
Methods
Patients with Walch B2 glenoids and pre-operative computed tomography (CT) scans were retrospectively identified. Two dimensional (2D) axial CT scans were reviewed and posterior bone loss was measured by three independent reviewers. Images were then formatted into BluePrint (Wright Medical, Memphis, TN, USA) pre-operative planning software. The same three reviewers again measured posterior bone loss on three-dimensional (3D) imaging. Additionally, all cases were planned with BluePrint software. An augment was utilized when the following criteria were unable to be satisfied with standard implants: <10° retroversion, <10° superior inclination, > 90% backside contact, <2mm medial reaming, and < 1 peg perforation.
Results
Forty-two patients were included in the final analysis with a mean age of 63.1±6.3 years. As measured by Blueprint, the mean retroversion was 23°±7° (range = 9° to 40°), the mean superior inclination was 5°±6° (range = -9° to 22°) and the mean posterior subluxation was 80±17% (range = 41% to 95%). The mean 2D bone loss measurements (3.5mm±1.6mm) were significantly lower than the mean 3D bone loss (4.0mm±1.8mm) measurements (P= .03). There was substantial agreement between reviewers on both 2D and 3D measurements with an inter-class correlation of 0.815 (P < .001; 95% CI: 0.714-0.889) and an inter-class correlation of 0.802 (P < .001; 95% CI: 0.683-0.884), respectively. Augments were utilized in 73.8%, 63.4% and 63.4% of cases by reviewers 1, 2, and 3, respectively, with moderate agreement with a Fleiss’ kappa of 0.592 (P < .001; 95%CI: 0.416-0.769). Augment size was moderately, positively correlated with amount of bone loss on 3D imaging but not with 2D imaging. After multivariate logistic regression, both 3D bone loss and retroversion were found to be predictive for a plan to use an augment.
Conclusion
Planning for a posterior augment in Walch B2 glenoids is better predicted with 3D imaging than with 2D imaging, as 2D imaging may underestimate posterior bone loss. Additionally, use of a larger augment size is moderately correlated with posterior bone loss on 3D imaging but not 2D imaging. Standard 2D imaging may be limited in cases of posterior bone loss and 3D imaging may be beneficial for preoperative planning in Walch B2 glenoids.
Background
: Treatment of glenohumeral osteoarthritis (OA) with Walch type B glenoid poses a challenge for orthopedic surgeons. Although various techniques have been described, it is still a major concern in terms of management and long-term results. We hypothesized that total shoulder arthroplasty (TSA) using a combination of non-spherical humeral head resurfacing (HHR) and inlay glenoid replacement would re-center the glenohumeral joint in patients with Walch type B glenoid without surgical correction of glenoid version.
Methods
: We retrospectively screened patients who underwent TSA using a combination of non-spherical HHR and inlay glenoid replacement for primary glenohumeral OA with posteriorly subluxated humeral head (HH) (Walch Type B1, B2 and B3) between 2015 and 2019. Ratios of preoperative and postoperative HH subluxation were compared using Walch index and the point of contact ratio method. Two orthopedic surgeons performed radiographic measurements blinded to each other. Means of two independent measurements were included in the final analysis for each shoulder. We also screened for postoperative complications, dislocation events and radiographic loosening.
Results
: Initial cohort included 49 patients. A total of 29 shoulders in 28 patients were eligible for screening. The numbers of shoulders with Walch type B1, B2 and B3 glenoids were 3, 22 and 4, respectively. Mean preoperative and postoperative Walch indicis were 56.57±6.08% and 49.47±4.78%, respectively. The mean preoperative and postoperative point of contact ratios were 62.97±8.45% and 50.08±3.87%, respectively. The difference between preoperative and postoperative subluxation ratios was significant for both methods (p<0.01). Inter-rater reliability was found to be good-excellent. The overall complication rate at a mean follow-up period of 37.79 months was 10.34% (3/29). One patient experienced deep vein thrombosis (DVT) (3.22%) on postoperative day 8. Two patients experienced infection (6.45%), one of which required a revision TSA (3.22%) at 19 months after surgery. No patient experienced shoulder dislocation and no loosening was detected on postoperative radiographs.
Conclusion
: When coupled with an inlay glenoid component in patients with eccentric glenoid wear and posterior subluxation, glenohumeral re-centering was consistently observed in this challenging patient population without the use of joint correction or augmentation procedures. It will be important to follow the clinical outcomes over the long-term to determine whether these observations translate to better clinical results than other techniques currently employed to deal with eccentric erosion and posterior subluxation of the arthritic glenohumeral joint although recent published mid-term results suggest results equal to or better than previously reported results in literature with different reconstructive techniques
Level of evidence
: Level IV; Retrospective Cohort
Background:
Publications regarding anatomic total shoulder arthroplasty (TSA) have consistently reported that they provide significant improvement for patients with glenohumeral arthritis. New TSA technologies that have been introduced with the goal of further improving these outcomes include preoperative computed tomography (CT) scans, 3-dimensional preoperative planning, patient-specific instrumentation, stemless and short-stemmed humeral components, as well as metal-backed, hybrid, and augmented glenoid components. The benefit of these new technologies in terms of patient-reported outcomes is unknown.
Methods:
We reviewed 114 articles presenting preoperative and postoperative values for commonly used patient-reported metrics. The results were analyzed to determine whether patient outcomes have improved over the 20 years during which new technologies became available.
Results:
The analysis did not identify evidence that the results of TSA were statistically or clinically improved over the 2 decades of study or that any of the individual technologies were associated with significant improvement in patient outcomes.
Conclusions:
Additional research is required to document the clinical value of these new technologies to patients with glenohumeral arthritis.
Level of evidence:
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Introduction
: Despite increasing utilization, little guidance is offered regarding appropriate indications for posterior augmented glenoid implants. The purpose of this study is to virtually assess the effect of implant selection on glenoid resurfacing and joint line restoration in osteoarthritic shoulders with posterior glenoid wear.
Methods
: Thirty-three CT scans were randomly selected from a cohort of osteoarthritic shoulders with Walch B2 or B3 deformities. Imascap SAS (Wright Medical, Memphis, TN) was used to assess bony deformities and plan glenoid resurfacing. Implants simulated included: standard Pegged Cortiloc, and 15° and 25° half-wedge augments. Each component was planned for a version correction to neutral and 10° retroversion, inclination was maintained within 5° of neutral and the component was medialized until bony support reached 80%. Implantation failure was defined as: greater than 20% cancellous bone support, central peg perforation, or joint line medialization relative to the pathologic joint (accounting for polyethylene thickness). Excessive lateralization was defined as creation of a joint-line >4mm lateral to the pathologic joint-line.
Results
: The mean retroversion deformity in this cohort was 23.7° (range: 13°-37°). When correcting to neutral, the corrective reaming alone failed in 72.7% (24/33) of cases compared to 15.2% (5/33) when correcting to 10° of implant retroversion. When correcting to neutral version failure was decreased with a 15° (27.3%; 9/33; p<0.001) and 25° augment (15.2%; 5/33; p<0.001). Receiver operating characteristic (ROC) analysis found that an augment is useful to resolve standard implant failure for retroversion deformities greater than 27° (area under the curve [AUC]=0.91) and 22° (AUC=0.77) for correcting version to neutral and 10° retroversion, respectively. When placing a 25° augment, there was high risk of overstuffing the joint for both correction to neutral (27.3%) and 10° retroversion (66.7%). Overstuffing was likely to occur when correcting deformities less than 19° (AUC=0.96) to neutral with a 25° augment. Likewise, implanting 15° or 25° augmented glenoids in 10° of retroversion is likely to overstuff the joint for pathologic retroversion deformities smaller than 18° (AUC=0.94) and 28° (AUC=0.69), respectively.
Conclusion
: This study helps to clarify the severity of glenoid deformities more appropriately addressed with the use of a half-wedged augmented glenoid. Both the severity of glenoid deformity and the desired implant version affect appropriate indications for the use of augmented glenoids. The risk of excessive joint-line lateralization in shoulders with less severe deformities should not be ignored. These considerations, in addition to individual soft tissue tension should be considered when planning and performing glenoid resurfacing.
Level of Evidence
: Level III; Treatment Study
Background
The primary objective of the present study was to investigate how preoperative imaging modalities including 3D computed tomography (CT) scans with preoperative planning software affect implant choice for shoulder arthroplasty.
Methods
X-ray, uncorrected 2D CT scans, and 3D CT scans from 21 patients undergoing primary arthroplasty were reviewed by five shoulder surgeons. Each surgeon measured glenoid version, inclination and humeral head subluxation, and then selected an anatomic or reverse shoulder arthroplasty implant based only on these imaging parameters. Each surgeon virtually positioned the implant. Agreement between surgeons and changes in plan for individual surgeons between imaging modalities were assessed.
Results
Average measurements of native version, inclination, and subluxation were similar across all imaging modalities with very good interobserver reliability. Overall, there was a high rate of variability in choice of implant depending on imaging modality. Agreement on implant selection between surgeons improved from 68.6% using x-ray to 80.0% with 3D CT. Introducing age added significant variability, reducing agreement on implant choice to 61.0% with 3D CT.
Conclusions
The use of preoperative 3D planning changes implant choice in nearly one-third of cases compared to plain radiographs and improves surgeon agreement on implant choice compared to x-ray and 2D CT. Level of evidence: III.
Background
Treatment of B2 glenoids in total shoulder arthroplasty (TSA) has been associated with worse clinical outcomes and increased rates of glenoid loosening. The purpose of this study was to describe and compare the mid-term outcomes of TSA using a trabecular metal-backed glenoid in patients with B2 and A glenoids.
Methods
Patients who underwent anatomic TSA with a trabecular metal-backed glenoid component (second generation trabecular metal glenoid) for primary osteoarthritis and had minimum 5-year follow-up were reviewed. All patients underwent eccentric glenoid reaming to treat biconcavity, if present. Preoperative imaging was reviewed and patients were divided into 2 groups: Type A and Type B2. Mid-term outcome measures including patient-rated outcome scores (Patient Reported Outcome Measurement Information System and American Shoulder and Elbow Surgeons [ASES]) and shoulder range of motion were determined. ASES score was compared between groups. Radiographs were graded for radiolucent lines and posterior humeral head migration and evaluated for glenoid loosening.
Results
Twenty-two patients had Type A glenoids and 22 patients had B2 glenoids. Sixteen patients in the A group and 18 patients in the B2 group had full radiographic and physical exam follow-up. Both groups had similar follow-up (6.7 ± 1.1 years A, 6.6 ± 0.9 years B2, P = .88). Groups were similar in terms of age at surgery, gender distribution, body mass index, severity of medical comorbidities, and hand dominance distribution. The B2 patients had a mean preoperative glenoid retroversion of 17.5° ± 6.7° and posterior subluxation of 8.5% ± 5.3%. No patients in either group had evidence of glenoid loosening at follow-up. No patients required revision surgery. Nine of 16 in the A group had evidence of mild radiolucent lines (8 grade 1, 1 grade 2). Eight of 18 patients in the B2 group had mild radiolucencies (all grade 1). Two of 16 Type A and 6 of 18 B2 patients had evidence of posterior humeral migration, but all cases were graded as mild. Both groups had similar follow-up mean ASES scores (95.5 A, 89.0 B2, P = .25).
Conclusion
At minimum 5-year follow-up, patients who underwent TSA with a trabecular metal-backed glenoid component demonstrated excellent clinical and patient-reported outcomes regardless of preoperative glenoid morphology (A or B2). No patients in either group had evidence of glenoid loosening or required revision surgery. These favorable mid-term outcomes of trabecular metal-backed glenoids in B2 deformities need to be followed longitudinally to determine long-term durability.
Level of Evidence
Level III; Retrospective Comparative Study
Background:. This study evaluated the ability of shoulder arthroplasty using a standard glenoid component to improve patient self-assessed comfort and function and to correct preoperative humeral-head decentering on the face of the glenoid in patients with primary glenohumeral arthritis and type-B2 or B3 glenoids.
Methods:. We identified 66 shoulders with type-B2 glenoids (n = 40) or type-B3 glenoids (n = 26) undergoing total shoulder arthroplasties with a non-augmented glenoid component inserted without attempting to normalize glenoid version and with clinical and radiographic follow-up that was a minimum of 2 years. The Simple Shoulder Test (SST), the percentage of humeral-head decentering on the glenoid face, and bone ingrowth into the central peg were the main outcome variables of interest. Similar analyses were made for concurrent patients with type-A1, A2, B1, and D glenoid pathoanatomy to determine if the outcomes for type-B2 and B3 glenoids were inferior to those for the other types.
Results:. The SST score (and standard deviation) improved from 3.2 ± 2.1 points preoperatively to 9.9 ± 2.4 points postoperatively (p < 0.001) at a mean time of 2.8 ± 1.2 years for type-B2 glenoids and from 3.0 ± 2.5 points preoperatively to 9.4 ± 2.1 points postoperatively (p < 0.001) at a mean time of 2.9 ± 1.5 years for type-B3 glenoids; these results were not inferior to those for shoulders with other glenoid types. Postoperative glenoid version was not significantly different (p > 0.05) from preoperative glenoid version. The mean humeral-head decentering on the glenoid face was reduced for type-B2 glenoids from −14% ± 7% preoperatively to −1% ± 2% postoperatively (p < 0.001) and for type-B3 glenoids from −4% ± 6% preoperatively to −1% ± 3% postoperatively (p = 0.027). The rates of bone integration into the central peg for type-B2 glenoids (83%) and type-B3 glenoids (81%) were not inferior to those for other glenoid types.
Conclusions:. Shoulder arthroplasty with a standard glenoid inserted without changing version can significantly improve patient comfort and function and consistently center the humeral head on the glenoid face in shoulders with type-B2 and B3 glenoids, achieving >80% osseous integration into the central peg. These clinical and radiographic outcomes for type-B2 and B3 glenoids were not inferior to those outcomes for other glenoid types.
Level of Evidence:. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Background:
Restoration of native glenohumeral joint line is important for a successful outcome after reverse shoulder arthroplasty (RSA). The aims of this study are to quantify the restoration of glenoid joint line after structural bone grafting and RSA, and to evaluate graft incorporation, correction of glenoid version, and rate of notching.
Methods:
This is a retrospective review of 21 patients who underwent RSA (20 primary, 1 revision) with glenoid bone grafting (15 autografts, 6 allografts). Grammont design implants and baseplate with long peg were used in all patients. Preoperative and postoperative 3D models were created using MIMICS 21.0 (Materialise, Belgium). Preoperative defects were classified and postoperative joint line restoration were assessed based on the lateral aspect of the base of the coracoid. Post-operative CT scans were evaluated for graft incorporation, version correction, and presence of notching.
Results:
Preoperative glenoid defects were classified as massive (5%), large (29%), moderate (52%), and small (14%). The average preoperative version was 8° of retroversion. The average postoperative version was 5° of retroversion. The average preoperative medialization was noted to be 8.5mm medial to native joint line or 0.5mm (range -16.8 - 13.2) lateral to the coracoid base. The postoperative CT scans demonstrated a mean joint line at 12.1mm (range 1.3 - 22.4) lateral to the coracoid base. At 3-month follow-up, all patients demonstrated graft incorporation on CT scans. Graft osteolysis was observed on CT scan in 4.8% of patients at mean follow-up of 19.5 months.
Discussion:
Structural bone grafting of glenoid defect effectively recreates the glenoid anatomy, restores glenoid bone stock, recreates the true glenohumeral joint line, and corrects glenoid deformity. The use of bone grafting also allows lateralization of the baseplate and glenosphere reducing risk of severe scapular notching.
Conclusion:
Restoration of glenoid joint line was achieved in all patients. Glenoid bone grafting is a viable option for restoring glenoid joint line in cases of significant glenoid defects encountered during RSA.
Level of evidence:
Level IV; Case Series; Treatment Study.
Background
Glenoid component loosening is a common cause of failure for anatomic total shoulder arthroplasty (TSA). Prior studies of all-polyethylene (PE) hybrid fixation glenoid implants did not show early glenoid radiolucency to be clinically significant. The purpose of this study was to determine the clinical significance of progression of radiolucency around the central peg of the glenoid component.
Methods
We identified 73 shoulders between January 1995 to May 2015 that underwent primary anatomic TSA for osteoarthritis with an all-PE pegged glenoid with a minimum follow-up interval of 2-years between early and late follow-up. Demographic, radiographic (central peg osteolysis [CPO] and grading) and outcome variables of Penn Shoulder Score (PSS) and revision surgery were collected. Clinical failure was defined as PSS decrease >11.4 or revision surgery.
Results
The average patient age at surgery was 65±7 and 63% were male. Median initial follow-up was 14 months [IQR 12-25] and final median follow-up was 56 months [IQR 47-69]. There were 4 revision surgeries and 17 PSS failures. We found CPO at final follow-up, central peg grade (CPG) progression, and worse PSS at follow-up were associated with revision surgery (p<0.05). We also found younger age at surgery, CPO at final follow-up, CPG progression, and greater glenoid component retroversion at final follow-up to be associated with clinical failure (PSS failure or revision surgery) (p<0.05). Multivariate analysis found only CPG progression to be associated with clinical failure (p<0.001).
Discussion/Conclusion
CPO and CPG progression were associated with clinical failure defined as decreasing clinical outcome scores or revision surgery.
Level of evidence
Level IV; Case Series; Treatment Study
Background
Glenoid retroversion and humeral head subluxation have been suggested to lead to inferior outcomes after total shoulder arthroplasty (TSA). There are limited data to support this suggestion. We investigated whether preoperative glenoid retroversion and humeral head subluxation are associated with inferior outcomes after TSA and whether change of retroversion influences outcomes after TSA.
Methods
Patients undergoing TSA with minimum 2-year follow-up were included from a prospectively-collected institutional shoulder arthroplasty database. Retroversion and humeral head subluxation before and after surgery were measured on axillary radiographs. Postoperative radiographs were evaluated for glenoid component loosening and compared between groups. Spearman correlations were determined between retroversion measurements and American Shoulder and Elbow Surgeons (ASES) scores. Patients were analyzed in groups based on retroversion and humeral head subluxation.
Results
There were 113 patients (50% follow-up rate) evaluated at 4.2 years postoperatively. The mean preoperative retroversion (15.3±7.7°) was significantly higher than postoperative retroversion (10.0±6.8°; p<0.0001). There was no correlation between postoperative glenoid version or humeral head subluxation and ASES scores. For patients with preoperative retroversion of >15o, there was no difference in outcome scores based on postoperative retroversion. There were no differences in preoperative or postoperative version for patients with or without glenoid lucencies.
Discussion
We observed no significant relationship between postoperative glenoid retroversion or humeral head subluxation and clinical outcomes in patients following TSA. For patients with preoperative retroversion >15, change of retroversion during TSA had no impact on their clinical outcomes at short-term follow-up.
The purpose of this study was to systematically assess the surgical techniques and outcomes related to the management of Walch B2 glenoids. PubMed, Medline, and Embase were searched from inception to July 2018. Overall, 24 studies (787 B2 glenoids) were identified. Revision-free survivorship was highest for reverse total shoulder arthroplasty (98.6%) and anatomic total shoulder arthroplasty with asymmetric reaming and a non-augmented glenoid implant (95.6%). Walch B2 glenoids are most commonly managed by asymmetric reaming in the context of anatomic total shoulder arthroplasty, and by the ream-and-run technique in hemiarthroplasty. The optimal treatment strategy remains elusive due to a lack of high-quality, comparative studies with long-term surveillance. [Orthopedics. 2020;43(4):e191–e201.]
Background:
Several modern designs of metal-backed glenoids (MBG) have been devised to overcome flaws such as loosening and a high failure rate. This review aimed to compare rates of complications and revision surgeries between cemented polyethylene glenoid (PEG) and three examples of modern MBG designs.
Methods:
Literature search was carried out using PubMed, Cochrane Library, EMBASE, and Google Scholar using MeSH terms and natural keywords. A total of 1186 articles were screened. We descriptively analyzed numerical data between the groups and statistically analyzed the categorical data, such as the presence of radiolucent line, loosening, and revision surgery (failure). Articles were divided into three groups based on follow-up duration: < 36-month, 36-72-month, and > 72-month subgroups.
Results:
This study included 35 articles (3769 shoulders); 25 on cemented PEG and ten on the modern MBG. Mean age was 66.4 (21-93) and 66.5 years (31-88). The mean duration of follow-up was 73.1 (12-211) and 56.1 months (24-100). Overall, the rate of the radiolucent line was 354/1302 (27%) and 47/282 (17%), the loosening rate was 465/3185 (15%) and 22/449 (5%), and the failure rate was 189/3316 (6%) and 11/457 (2%), for PEG and MBG, respectively. The results of < 36-month and 36-72-month subgroups showed lower rates of radiolucency and loosening in the cemented PEG group, but there was no significant difference in failure rate (P = 0.754 and 0.829, respectively). In the > 72-month subgroup, MBG was better in terms of loosening (P < 0.001) and failure rates (P = 0.006).
Conclusions:
The modern MBG component, especially TM glenoid, seems to be a promising alternative to cemented PEGs, based on subgroup revision rates according to the follow-up duration and overall results of ROM and clinical scores. All polyethylene glenoids tend to increase loosening and failure over time. Three modern MBG designs seem to have no difference in failure, at least in the < 36-month and 36-72-month subgroups compared to the cemented PEG. More long-term follow-up studies on modern MBG should be ultimately conducted.
Level of evidence:
Level IV, systematic review.
Background:
Axillary radiographs traditionally have been considered sufficient to identify concentric glenoid wear in osteoarthritic shoulders; however, with variable glenoid wear patterns, assessment with use of computed tomography (CT) has been recommended. The purpose of the present study was to compare the use of axillary radiographs and mid-glenoid axial CT scans to identify glenoid wear.
Methods:
Preoperative axillary radiographs and mid-glenoid axial CT scans for 330 patients who underwent anatomic total shoulder arthroplasty were reviewed. Five independent examiners with differing levels of experience characterized the glenoid morphology as either concentric or eccentric. The morphologies determined with use of axillary radiographs and CT scans were assessed for correlation, and both intraobserver and interobserver consistency were calculated.
Results:
Concentric wear identified with use of radiographs was confirmed with use of CT scans in an average of 61% of cases (range, 53% to 76%). Intraobserver consistency averaged 75% for radiographs and 73% for CT scans. There was significant interobserver consistency, as higher levels of training corresponded with greater consistency between imaging analyses (p < 0.001). The most senior observer identified the highest proportion of concentric wear on radiographs (p < 0.001), showed the greatest consistency between attempts when using CT (p < 0.001), and had the greatest agreement of radiographs and CT evaluating glenoid morphology (p < 0.001).
Conclusions:
For the experienced shoulder surgeon, concentric glenoid wear identified on axillary radiographs will appear concentric on 2-dimensional CT in approximately 75% of cases. Obtaining a CT scan to confirm glenoid wear patterns most greatly benefits less-experienced surgeons. Across all levels of experience, axillary radiographs and single-slice, mid-glenoid CT scans appear insufficient for consistently predicting wear patterns.
Level of evidence:
Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.
Background:
Both anatomic and reverse total shoulder arthroplasty are considered successful surgeries to treat a variety of painful shoulder conditions. Although implant survivorship for both is good to excellent in the long term, a variety of factors-clinical, technical, and psychosocial-may affect patient-reported outcomes after shoulder arthroplasty.
Methods:
A comprehensive review of the literature was performed systematically using keywords "shoulder arthroplasty outcomes," "psychosocial factors shoulder," "shoulder replacement outcomes," "depression shoulder arthroplasty," "satisfaction shoulder arthroplasty," "factors shoulder replacement," "expectations shoulder arthroplasty," and "predictors shoulder arthroplasty." Studies meeting the inclusion criteria were screened and analyzed. Type of surgery performed, sample size, outcome measures, and other factors influencing patient outcomes were recorded and analyzed.
Results:
Sixteen studies met the inclusion criteria. Six reviewed mental health disorders as predictors of postoperative outcome after shoulder arthroplasty. Of these, 4 found that disorders such a depression and anxiety were associated with increased risk of perioperative complications and lower final functional outcome scores. Two studies evaluated workers' compensation status as a possible predictor of outcomes and found that patients with claims had lower satisfaction and outcome scores at final follow-up compared with those without claims. Two studies showed that preoperative opioid use was associated with lower outcome scores and overall satisfaction rate after shoulder arthroplasty. Three studies showed that higher patient confidence and preoperative expectations were correlated with better outcomes.
Conclusion:
Our review shows that psychosocial factors may play just as important role in affecting patient outcomes after total shoulder arthroplasty as technical factors.
Background:
There is great current interest in characterizing the prearthroplasty glenohumeral pathoanatomy because of its role in guiding surgical technique and its possible effects on arthroplasty outcome.
Methods:
We examined 544 patients within 6 weeks before arthroplasty with the goals of characterizing the following: demographic and radiographic characteristics; relationships of the radiographic pathoanatomy to the patient's age, sex, and diagnosis; inter-relationships among glenoid type, glenoid version, and amount of decentering of the humeral head on the glenoid; and relationships of the pathoanatomy to the patient's self-assessed comfort and function.
Results:
Male patients had a higher frequency of B2 glenoids and a lower frequency of A2 glenoids. The arthritic shoulders of men were more retroverted and had greater amounts of posterior decentering. Patients with types A1 and C glenoids were younger than those with other glenoid types. Shoulders with osteoarthritis were more likely to be type B2 and to be retroverted. Types B2 and C had the greatest degree of retroversion, whereas types B1 and B2 had the greatest amounts of posterior decentering. Shoulders with glenoid types B1 and B2 and those with more decentering did not have worse self-assessed shoulder comfort and function.
Conclusions:
Glenohumeral pathoanatomy was found to have previously unreported relationships to the patient's sex, age, and diagnosis. Contrary to what might have been expected, more advanced glenohumeral pathoanatomy (ie, type B glenoids, greater retroversion, greater decentering) was not associated with worse self-assessed shoulder comfort and function.
Background:
The number of total shoulder arthroplasties (TSAs) performed is increasing annually, with a continued effort to improve outcomes using new techniques and materials. In anatomic TSAs, the main options for glenoid fixation currently involve keeled or pegged components. The aim of this review was to determine which fixation option provides optimal long-term functional outcomes with decreased rates of revision surgery and radiolucency.
Methods:
The MEDLINE, Embase, PubMed, and Cochrane databases were searched from 2007 to July 10, 2017, for all articles that examined TSAs using either pegged or keeled glenoid fixations. All studies were screened in duplicate for eligibility. Two separate analyses were completed examining noncomparative and comparative studies independently.
Results:
A total of 7 comparative studies and 25 noncomparative studies were included in the final analysis. Included in the analysis were 4 randomized (level I) studies, 1 level II study, 8 level III studies, and 19 level IV studies. Meta-analysis of the comparative studies demonstrated a higher rate of revision surgery with keeled fixations compared with pegged fixations (odds ratio, 6.22; 95% confidence interval [CI], 1.38-28.1; P = .02). No significant difference was found with respect to functional outcomes, such as the American Shoulder and Elbow Surgeons score (mean difference, 9.54; 95% CI, -8.25 to 27.34; P = .29) and Constant score (mean difference, 5.31; 95% CI, -12.28 to 22.89; P = .55), as well as radiolucency rates (odds ratio, 1.89; 95% CI, 0.56-6.39; P = .30).
Conclusion:
Pegged glenoid fixation may result in a decreased risk of revision TSAs, but no significant differences in patient-reported outcomes have been identified to date.
Purpose
Total shoulder (TSA) is commonly used to treat arthritic shoulders with intact rotator cuffs; however, some patients choose a ream and run (RnR) to avoid the potential risks and limitations of a prosthetic glenoid component. Little is known about how patients selecting each of these two procedures compare and contrast.
Methods
We analyzed the patient characteristics, shoulder characteristics, and two year clinical outcomes of 544 patients having RnR or TSA at the same institution during the same six year period.
Results
Patients selecting the RnR were more likely to be male (92.0% vs. 47.0%), younger (58 ± 9 vs. 67 ± 10 years), married (83.2% vs. 66.8%), from outside of our state (51.7% vs. 21.7%), commercially insured (59.1% vs. 25.2%), and to have type B2 glenoids (46.0% vs. 27.8%) as well as greater glenoid retroversion (19 ± 11 vs. 15 ± 11 degrees) (p < .001). The average two year SST score for the RnRs was 10.0 ± 2.6 vs. 9.5 ± 2.7 for the TSAs. The percent of maximum possible improvement (%MPI) for the RnRs averaged 72 ± 39% vs. 73 ± 29% for the TSAs. Patients with work-related shoulder problems had lower two year SSTs and lower %MPIs. Younger patients having TSAs did less well than older patients. Female patients having RnRs did less well than those having TSAs (p < 0.001).
Conclusions
This investigation highlights important characteristics of patients selecting the RnR and the TSA for glenohumeral arthritis. Excellent outcomes can be achieved for appropriately selected patients having either procedure.
Background:
Although shoulder arthroplasties generally are effective in improving patients' comfort and function, the results are variable for reasons that are not well understood.
Questions/purposes:
We posed two questions: (1) What factors are associated with better 2-year outcomes after shoulder arthroplasty? (2) What are the sensitivities, specificities, and positive and negative predictive values of a multivariate predictive model for better outcome?
Methods:
Three hundred thirty-nine patients having a shoulder arthroplasty (hemiarthroplasty, arthroplasty for cuff tear arthropathy, ream and run arthroplasty, total shoulder or reverse total shoulder arthroplasty) between August 24, 2010 and December 31, 2012 consented to participate in this prospective study. Two patients were excluded because they were missing baseline variables. Forty-three patients were missing 2-year data. Univariate and multivariate analyses determined the relationship of baseline patient, shoulder, and surgical characteristics to a "better" outcome, defined as an improvement of at least 30% of the maximal possible improvement in the Simple Shoulder Test. The results were used to develop a predictive model, the accuracy of which was tested using a 10-fold cross-validation.
Results:
After controlling for potentially relevant confounding variables, the multivariate analysis showed that the factors significantly associated with better outcomes were American Society of Anesthesiologists Class I (odds ratio [OR], 1.94; 95% CI, 1.03-3.65; p = 0.041), shoulder problem not related to work (OR, 5.36; 95% CI, 2.15-13.37; p < 0.001), lower baseline Simple Shoulder Test score (OR, 1.32; 95% CI, 1.23-1.42; p < 0.001), no prior shoulder surgery (OR, 1.79; 95% CI, 1.18-2.70; p = 0.006), humeral head not superiorly displaced on the AP radiograph (OR, 2.14; 95% CI, 1.15-4.02; p = 0.017), and glenoid type other than A1 (OR, 4.47; 95% CI, 2.24-8.94; p < 0.001). Neither preoperative glenoid version nor posterior decentering of the humeral head on the glenoid were associated with the outcomes. The model predictive of a better result was driven mainly by the six factors listed above. The area under the receiver operating characteristic curve generated from the cross-validated enhanced predictive model was 0.79 (generally values of 0.7 to 0.8 are considered fair and values of 0.8 to 0.9 are considered good). The false-positive fraction and the true-positive fraction depended on the cutoff probability selected (ie, the selected probability above which the prediction would be classified as a better outcome). A cutoff probability of 0.68 yielded the best performance of the model with cross-validation predictions of better outcomes for 236 patients (80%) and worse outcomes for 58 patients (20%); sensitivity of 91% (95% CI, 88%-95%); specificity of 65% (95% CI, 53%-77%); positive predictive value of 92% (95% CI, 88%-95%); and negative predictive value of 64% (95% CI, 51%-76%).
Conclusions:
We found six easy-to-determine preoperative patient and shoulder factors that were significantly associated with better outcomes of shoulder arthroplasty. A model based on these characteristics had good predictive properties for identifying patients likely to have a better outcome from shoulder arthroplasty. Future research could refine this model with larger patient populations from multiple practices.
Level of evidence:
Level II, therapeutic study.
Aseptic glenoid component loosening remains a common problem in total shoulder arthroplasty (TSA). This study presents long-term prospective follow-up after implantation of a glenoid component using the "cancellous compaction technique" and its effect on clinical outcome and presence and progression of radiolucent lines (RLLs).
Thirty-nine TSAs were performed for primary osteoarthritis by one surgeon using the same technique. For the glenoid side, a keeled, polyethylene, convex-backed component was implanted using the "cancellous compaction technique" consisting of minimal reaming, compaction bone grafting of the glenoid and minimal addition of cement. Postoperative clinical outcome was analysed using Constant scores and patient's subjective evaluation. Independent observers evaluated postoperative X-rays for radiolucent lines (RLL) around the base plate and keel.
At an average follow-up of 8.5 years (range 4.7-12.5), the Constant score improved from 33.5 to 73.0 points (P < 0.0001). Active anterior elevation improved from an average 95 ° to 140° (P < 0.0001), and active external rotation improved from 20° to 45° (P < 0.0001). Pain score improved from 3.1 to 13.6 (P < 0.0001). Radiologically, the RLL score increased from 1.09 (range, 0-3) postoperative to 5.7 (range, 0-18) (P < 0.0001) at final follow-up. The occurrence of definite radiological glenoid loosening was 15.5 %. Constant scores deteriorated with the progression of RLLs (P = 0.006). The rate of revision surgery for glenoid loosening was 2.5 %.
This study showed highly satisfactory clinical outcomes and low rates of revision for glenoid loosening using a bone-saving compaction technique for implantation of an all-polyethylene glenoid component.
Background:
The arthritic triad of glenoid biconcavity, glenoid retroversion, and posterior displacement of the humeral head on the glenoid is associated with an increased risk of failure of total shoulder joint replacement. Although a number of glenohumeral arthroplasty techniques are being used to manage this complex pathology, problems with glenoid component failure remain. In that the ream and run procedure manages arthritic pathoanatomy without a glenoid component, we sought evidence that this procedure can be effective in improving the centering of the humeral head contact on the glenoid and in improving the comfort and function of shoulders with the arthritic triad without the risk of glenoid component failure.
Questions/purposes:
We asked, for shoulders with the arthritic triad, whether the ream and run procedure could improve glenohumeral relationships as measured on standardized axillary radiographs and patient-reported shoulder comfort and function as recorded by the Simple Shoulder Test.
Methods:
Between January 1, 2006 and December 14, 2011, we performed 531 primary anatomic glenohumeral arthroplasties for arthritis, of which 221 (42%) were ream and run procedures. Of these, 30 shoulders in 30 patients had the ream and run procedure for the arthritic triad and had two years of clinical and radiographic follow-up. These 30 shoulders formed the basis for this case series. The average age of the patients was 56 ± 8 years; all but one were male. Two of the 30 patients requested revision to total shoulder arthroplasty within the first year after their ream and run procedure because of their dissatisfaction with their rehabilitation progress. For the 28 shoulders not having had a revision, we determined on the standardized axillary views before and after surgery the glenoid type, glenoid version (90° minus the angle between the plane of the glenoid face and the plane of the body of the scapula), and location of the humeral contact point with respect to the anteroposterio dimension of the glenoid (the ratio of the distance from the anterior glenoid lip to the contact point divided by the distance between the anterior and posterior glenoid lips). We also recorded the patient's self-assessed shoulder comfort and function before and after surgery using the 12 questions of the Simple Shoulder Test.
Results:
For the 28 unrevised shoulders the mean followup was 3.0 years (range, 2-9.2 years). In these patients, the ream and run procedure resulted in improved centering of the humeral head on the face of the glenoid (preoperative: 75% ± 7% posterior; postoperative: 59% ± 10% posterior; mean difference 16% [95% CI, 13%-19%]; p < 0.001), notably this improved centering was achieved without a significant change in the glenoid version. Patient-reported function was improved (preoperative Simple Shoulder Test: 5 ± 3, postoperative Simple Shoulder Test: 10 ± 4, mean difference 5 [95% CI, 4-6], p < 0.001).
Conclusions:
For shoulders with the arthritic triad, the ream and run procedure can provide improvement in humeral centering on the glenoid and in patient-reported shoulder comfort and function without the risk of glenoid component failure. In that ream and run is a new procedure, substantial additional clinical research with long-term follow-up is needed to define specifically the shoulder characteristics, the patient characteristics and the technical details that are most likely to lead to durable improvements in the comfort and function of shoulders with the challenging pathology known as the arthritic triad.
Level of evidence:
Level IV, therapeutic study.
The effective evaluation and management of orthopaedic conditions including shoulder disorders relies upon understanding the level of disability created by the disease process. Validated outcome measures are critical to the evaluation process. Traditionally, outcome measures have been physician derived objective evaluations including range of motion and radiologic evaluations. However, these measures can marginalize a patient's perception of their disability or outcome. As a result of these limitations, patient self-reported outcomes measures have become popular over the last quarter century and are currently primary tools to evaluate outcomes of treatment. Patient reported outcomes measures can be general health related quality of life measures, health utility measures, region specific health related quality of life measures or condition specific measures. Several patients self-reported outcomes measures have been developed and validated for evaluating patients with shoulder disorders. Computer adaptive testing will likely play an important role in the arsenal of measures used to evaluate shoulder patients in the future. The purpose of this article is to review the general health related quality-of-life measures as well as the joint-specific and condition specific measures utilized in evaluating patients with shoulder conditions. Advances in computer adaptive testing as it relates to assessing dysfunction in shoulder conditions will also be reviewed.
A subset of patients undergoing primary total shoulder arthroplasty (TSA) have a medialized joint line secondary to glenoid wear. In some cases, the central pegs or peripheral pegs of a peg design glenoid component may violate the medial cortex of the glenoid vault. It is unknown whether this leads to early failure. The objectives of this study were to determine (1) whether glenoid components with uncontained pegs would be associated with a high rate of failure and (2) whether peg perforation would be associated with inferior clinical outcomes. The authors performed a case-control retrospective review comparing 25 TSAs in which one or multiple pegs perforated the medial glenoid vault (uncontained group) with 25 TSAs without peg perforation (contained group). Implant survival was calculated with revision for glenoid component loosening as the primary outcome variable. Clinical outcomes were determined using American Shoulder and Elbow Surgeons (ASES) and Penn Shoulder Scores. Average follow-up was more than 5 years. No patient in either group had symptomatic glenoid loosening. Two (8%) patients in the uncontained group required revision for rotator cuff tears. Penn and ASES scores were significantly lower in the uncontained group (Penn, P=.002; ASES, P=.004). Pain and satisfaction subscores were similar between the groups, but function subscores were significantly lower in the uncontained group (Penn, P=.002; ASES, P=.005). Uncontained pegs of an anchor peg glenoid component are not associated with early glenoid loosening. Similar pain relief is obtained when compared with contained glenoid components, but shoulder function is significantly lower in patients with uncontained pegs.
The technique and results of shoulder arthroplasty are influenced by glenohumeral pathoanatomy. Although some authors advocate a routine preoperative CT scan to define this anatomy, ordering a CT scan substantially increases the cost and the radiation exposure for the patient.
We asked whether measurements of arthritic shoulders on a standardized axillary view are reliable; if postoperative radiographs can reliably show the changes in glenoid anatomy and glenohumeral relationships after shoulder arthroplasty, and if the axillary view can show differences in glenohumeral pathoanatomy in the different sexes and disease types.
These questions were addressed using cross-sectional studies of 344 shoulders with different types of arthritis and of 128 osteoarthritic shoulders having a ream and run arthroplasty (a glenohumeral arthroplasty that combines a noncemented humeral hemiarthroplasty with concentric reaming of the glenoid bone without implantation of a prosthetic glenoid component). Measurements of glenoid type, glenoid version, and glenohumeral contact were made on standardized axillary radiographs. Interobserver reliability was calculated, preoperative and postoperative measurements were compared, and morphologic differences were compared as stratified by sex and disease type.
The measurements on axillary views showed a high degree of interobserver reliability and sensitivity to the changes effected by arthroplasty. The ream and run substantially corrected the glenoid type and point of glenohumeral contact. Male shoulders and shoulders with osteoarthritis had more type B glenoids (ie, those with posterior erosion and biconcavity of the glenoid), more retroversion, and a greater degree of posterior displacement of the point of glenohumeral contact.
The axillary view provides a practical method of characterizing glenohumeral anatomy before and after surgery that is less costly and exposes the patient to less radiation than a CT scan.
Level IV, diagnostic study. See the Instructions for Authors for a complete description of levels of evidence.
The validation of widely used scales facilitates the comparison across international patient samples. The objective of this study was to translate, culturally adapt and validate the Simple Shoulder Test into Brazilian Portuguese. Also we test the stability of factor analysis across different cultures.
The objective of this study was to translate, culturally adapt and validate the Simple Shoulder Test into Brazilian Portuguese. Also we test the stability of factor analysis across different cultures.
The Simple Shoulder Test was translated from English into Brazilian Portuguese, translated back into English, and evaluated for accuracy by an expert committee. It was then administered to 100 patients with shoulder conditions. Psychometric properties were analyzed including factor analysis, internal reliability, test-retest reliability at seven days, and construct validity in relation to the Short Form 36 health survey (SF-36).
Factor analysis demonstrated a three factor solution. Cronbach's alpha was 0.82. Test-retest reliability index as measured by intra-class correlation coefficient (ICC) was 0.84. Associations were observed in the hypothesized direction with all subscales of SF-36 questionnaire.
The Simple Shoulder Test translation and cultural adaptation to Brazilian-Portuguese demonstrated adequate factor structure, internal reliability, and validity, ultimately allowing for its use in the comparison with international patient samples.
Posterior glenoid bone loss often is seen in association with glenohumeral osteoarthritis. Many different techniques have been proposed to account for this bone loss during total shoulder arthroplasty, the most popular being eccentric anterior reaming. However, the amount of correction that can be achieved has not been been well quantified. The purpose of this study was to define the amount of eccentric posterior glenoid wear that can be corrected by anterior glenoid reaming. Eight cadaveric scapulae were studied. Simulations of posterior glenoid wear in 5° increments were performed on each scapula. The specimens were then eccentrically reamed to correct the deformity. Anteroposterior width, superior-inferior height, and the best-fit pegged glenoid prosthesis size were measured. Anterior reaming to correct a 10° posterior defect resulted in a decrease in anteroposterior glenoid diameter from 26.7±2.5 mm to 23.8±3.1 mm (P=.006). In 4 of 8 specimens, placing a glenoid prosthesis was not possible after correcting a 15° deformity because of inadequate bony support (N=2), peg penetration (N=1) or both (N=1). A 20° deformity was correctable in 2 of 8 specimens and only after downsizing the glenoid component. Anterior glenoid reaming to correct eccentric posterior wear of ⩾10° results in significant narrowing of the anteroposterior glenoid width. A 15° deformity has only a 50% chance of successful correction by anterior, eccentric reaming. Orthopedic surgeons need to be cognizant of this in their preoperative planning for total shoulder arthroplasty.
We studied the natural course and the possibility of making a prognostic classification of glenoid morphology in primary glenohumeral osteoarthritis (GHOA). For this purpose, serial computed tomography scans of 113 osteoarthritic shoulders were reviewed. The position of the humeral head with respect to the glenoid seems to be an important predictor of the glenoid morphologic evolution. Three main glenoid types were defined: Type A, Type B, Type C. Type A (59%) was marked by a well-centered humeral head and a balanced distribution of strengths against the surface of the glenoid. The symmetric erosion was explained by the absence of subluxation. In Type B (32%), the posterior subluxation of the humeral head was responsible for the asymmetric load against the glenoid and was implicated in the development of primary GHOA, particularly the exaggerated posterior wear pattern. Type C (9%) was defined by a glenoid retroversion of more than 25 degrees, regardless of erosion; retroversion was primarily of dysplastic origin and explained the early event of osteoarthritis. In primary GHOA, this classification of the glenoid can discriminate retroversion between posterior erosion and dysplasia.
Background
The Simple Shoulder Test (SST) is a brief, inexpensive, and widely used patient-reported outcome tool, but it has not been rigorously evaluated for patients having shoulder arthroplasty. The goal of this study was to rigorously evaluate the validity of the SST for outcome assessment in shoulder arthroplasty using a systematic review of the literature and an analysis of its properties in a series of 408 surgical cases.
Methods
SST scores, 36-Item Short Form Health Survey scores, and satisfaction scores were collected preoperatively and 2 years postoperatively. Responsiveness was assessed by comparing preoperative and 2-year postoperative scores. Criterion validity was determined by correlating the SST with the 36-Item Short Form Health Survey. Construct validity was tested through 5 clinical hypotheses regarding satisfaction, comorbidities, insurance status, previous failed surgery, and narcotic use.
Results
Scores after arthroplasty improved from 3.9 ± 2.8 to 10.2 ± 2.3 (P < .001). The change in SST correlated strongly with patient satisfaction (P < .001). The SST had large Cohen's d effect sizes and standardized response means. Criterion validity was supported by significant differences between satisfied and unsatisfied patients, those with more severe and less severe comorbidities, those with workers' compensation or Medicaid and other types of insurance, those with and without previous failed shoulder surgery, and those taking and those not taking narcotic pain medication before surgery (P < .005).
Conclusion
These data combined with a systematic review of the literature demonstrate that the SST is a valid and responsive patient-reported outcome measure for assessing the outcomes of shoulder arthroplasty.
A novel technique of “anterior offsetting” of the humeral head component to address posterior instability in total shoulder arthroplasty has been proposed, and its biomechanical benefits have been previously demonstrated experimentally. The present study sought to characterize the changes in joint mechanics associated with anterior offsetting with various amounts of glenoid retroversion using cadaver specimen-specific 3-dimensional finite element models. Specimen-specific computational finite element models were developed through importing digitized locations of six musculotendinous units of the rotator cuff and deltoid muscles based off three cadaveric shoulder specimens implanted with total shoulder arthroplasty in either anatomic or anterior humeral head offset. Additional glenoid retroversion angles (0°, 10°, 20°, and 30°) other than each specimen's actual retroversion were modeled. Contact area, contact force, peak pressure, center of pressure, and humeral head displacement were calculated at each offset and retroversion for statistical analysis. Anterior offsetting was associated with significant anterior shift of center of pressure and humeral head displacement upon muscle loading (p<0.05). Although statistically insignificant, anterior offsetting was associated with increased contact area and decreased peak pressure (p > 0.05). All study variables showed significant differences when compared between the 4 different glenoid retroversion angles (p > 0.05) except for total force (p > 0.05). The study finding suggests that the anterior offsetting technique may contribute to joint stability in posteriorly unstable shoulder arthroplasty and may reduce eccentric loading on glenoid components although the long term clinical results are yet to be investigated in future.
Background:
Chronic osteoarthritis can result in glenohumeral subluxation and loss of posterior glenoid bone. This can alter normal glenohumeral biomechanics and affect the stress placed on the glenoid implant after total shoulder arthroplasty. This study evaluated the clinical and radiographic results of an augmented all-polyethylene glenoid for the treatment of glenoid osteoarthritis in the presence of posterior glenoid bone loss and determined whether any failures or complications occurred with short-term follow-up.
Methods:
During a 2-year period, 21 patients were treated with an augmented glenoid for an index diagnosis of osteoarthritis with a biconcave glenoid and average posterior glenoid bone loss of 4.7 mm. Clinical outcomes were recorded for the American Shoulder and Elbow Surgeons Shoulder Assessment, Simple Shoulder Test, and active motion. Radiographic analysis included glenoid version, humeral head subluxation, component seating, ingrowth, and loosening.
Results:
Significant improvements were demonstrated for American Shoulder and Elbow Surgeons Shoulder Assessment (52.3), Simple Shoulder Test (8.1), forward flexion (50°), external rotation (32°), and pain. Radiographic improvements were found for glenoid version (12°), humeral scapular alignment (23%), and humeral glenoid alignment (8%). Central peg ingrowth was demonstrated in all patients, and complete component seating was achieved in 19 patients. No complications were encountered, and no clinical or radiographic failures were identified.
Conclusion:
Augmented polyethylene glenoid components demonstrated improved clinical outcome, without implant failure or complications, during short-term follow-up.
Background
In selected patients with a desire to maintain activity levels greater than those recommended after reverse total shoulder arthroplasty, hemiarthroplasty remains an option for treatment of cuff tear arthropathy (CTA). However, given the relatively small case series that have been reported to date, little is known regarding which patients will show functional improvement after this surgery. Questions/purposesWe asked: What factors are associated with achieving the minimum clinically important difference in the simple shoulder test (SST) after hemiarthroplasty for cuff tear arthropathy? Patients and Methods
Between 1991 and 2007, two surgeons at one academic center performed 48 shoulder hemiarthroplasties for CTA. No patients were known to have died before data collection, and of those not known to have died, 42 (88%) were available for followup at a mean of 48 months (range, 24–132 months). During that time, the general indications for this approach were glenohumeral arthritis with superior decentering of the humeral head. The majority of the patients with CTA were treated nonoperatively with patient-directed physical therapy and other modalities. A total of 42 patients (42 shoulders; 24 males and 18 females) with CTA were treated with hemiarthroplasty and followed for a mean of 48 months (range, 24–132 months). This is a retrospective study that made use of a longitudinally maintained database, which included physical examination of ROM, the SST, VAS, and standardized radiographs. At latest followup, 33 of 42 patients achieved a clinically important percentage of maximum possible improvement (%MPI) in SST score, defined as an improvement of 30% of the total possible improvement on the 12-point scale (with higher scores representing better results). ResultsIntraoperative findings of a rotator cuff tear limited to the supraspinatus and infraspinatus (odds ratio [OR], ∞; 95% CI, 2.01 to ∞; p = 0.020) and limited preoperative external rotation (15° [range, −40° to 45°] vs 35° [range, 20°–45°], OR, 0.71; 95% CI, 0.38–0.90; p < 0.001) were associated with achieving the defined minimum functional improvement (30% of MPI) on multivariate analysis. Preoperative active elevation (p = 0.679) and use of a CTA-specific implant (p = 0.707) were not significantly associated with achievement of 30% of MPI. Conclusion
Patients with intact teres minor and subscapularis tendons and patients with lower preoperative external rotation had a better prognosis for achieving a clinically important percentage of MPI at short-term followup. Although some patients were followed for more than 10 years, the majority were followed for fewer than 5 years; future studies will need to determine whether these early functional results are maintained for longer periods. Level of EvidenceLevel III, therapeutic study.
Background:
Loosening of the glenoid component continues to be the main cause of medium and long-term failure of shoulder replacements. The purpose of this study was to evaluate the early clinical and radiographic results following use of an all-polyethylene pegged glenoid component designed for hybrid (biological and cement) fixation.
Methods:
Eighty-three shoulders in 77 patients (mean age, 68.6 years) underwent total shoulder arthroplasty with a pegged hybrid-fixation component (bone-ingrowth glenoid and cemented peg). Outcomes were determined with the American Shoulder and Elbow Surgeons (ASES) score and the Oxford shoulder score. A detailed analysis of radiographs and fine-slice computed tomography (CT) images was performed to determine the extent of bone ingrowth between the flanges and the extent of radiolucent lines at the prosthesis-bone interface.
Results:
The mean duration of follow-up was 46.7 months (range, 24 to 99 months). At the time of final follow-up, the median ASES score was 97 points (range, 43 to 100 points) and the median Oxford score was 48 points (range, 24 to 48 points). The median active forward elevation was 130° (range, 65° to 170°), median external rotation was 45° (range, 5° to 80°), and median internal rotation was to T11 (range, buttock to T4). Seventy-eight shoulders demonstrated a perfect Lazarus score for radiolucency (0, indicating no radiolucency). Sixty-eight shoulders demonstrated complete osseointegration, with bone ingrowth between all of the flanges seen on coronal CT; 5 demonstrated partial osseointegration; and 10 demonstrated osteolysis around the central peg. Most radiolucent lines were in the inferior Yian zones. There were no correlations between the Yian CT scores and either the ASES or Oxford score (rho = 0.13 and 0.07, respectively).
Conclusions:
Total shoulder arthroplasty with an all-polyethylene pegged glenoid component, utilizing hybrid fixation, demonstrated excellent clinical and radiographic results at the time of early follow-up. Radiolucent lines were seen most commonly around the inferior pegs of the prosthesis, and this may represent an incipient mode of failure.
Level of evidence:
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Background:
When fixed with bone ingrowth, a tight diaphyseal press fit, or cement, the humeral component of a shoulder arthroplasty may present problems of malposition, stress shielding, or periprosthetic fracture or difficulty with removal at revision arthroplasty. We have avoided the need for these fixation methods by using impaction cancellous autografting of the humeral stem, minimizing contact between the prosthetic stem and the humeral cortex. This study presents the radiographic survivorship of impaction-autografted humeral implants using component subsidence as the primary endpoint.
Methods:
We reviewed 286 primary anatomic shoulder arthroplasties having an average follow-up of 4.9 ± 2.7 years. Initial postoperative radiographs and minimum 2-year follow-up radiographs were evaluated by 3 observers to assess subsidence.
Results:
Two different implants (Humeral Replacement Prosthesis [HRP] and Global Advantage prosthesis) were used. Of 286 stems, 267 (93.4%) had not subsided. The Global Advantage prosthesis had a subsidence-free survival rate of 98.5% at 5 years. The stiffer-stemmed HRP used early during the study had a higher rate of subsidence compared with the currently used Global Advantage stem (hazard ratio, 5.6; P = .001). Radiolucent lines of 2 mm or greater were less common for the Global Advantage prosthesis than for the HRP in each of 7 zones (P < .001). Total shoulder arthroplasty was associated with a higher rate of subsidence compared with hemiarthroplasty (hazard ratio, 2.6; P = .12).
Conclusions:
Impaction autografting provides a secure, durable, bone-preserving means of humeral component fixation in anatomic shoulder arthroplasty.
Background:
Posterior glenoid bone loss is commonly encountered in total shoulder arthroplasty (TSA). The purpose of our study is to report the clinical and radiographic findings of patients with a minimum of 2 years' follow-up treated with an all-polyethylene, augmented glenoid component.
Methods:
Twenty-two shoulders with posterior glenoid bone loss were treated by a single surgeon. All underwent primary TSA using a posteriorly augmented, all-polyethylene, stepped glenoid component. Outcome data included visual analog scale, Western Ontario Osteoarthritis of the Shoulder index, and Short Form 36 scores. Radiographic analysis was performed to evaluate bone-cement interface lucency, implant seating, and osseous integration of the central peg.
Results:
The mean follow-up period was 36 months. Average preoperative retroversion measured with computed tomography scan was 23.5°. In addition to statistically significant increases in forward flexion and external rotation, the visual analog scale score, Western Ontario Osteoarthritis of the Shoulder score, and Short Form 36 physical component summary score all improved significantly (P < .001). Twelve shoulders had osseous integration between the central-peg flanges, 6 had bone adjacent to the central-peg flanges but without identifiable osseous integration, and 1 showed osteolysis. The mean Lazarus score was 0.5. All glenoids had perfect seating scores. Two patients sustained a total of 3 episodes of prosthetic instability.
Conclusions:
Early results of a posteriorly augmented, all-polyethylene, stepped prosthetic glenoid component to address posterior glenoid loss in TSA are encouraging. Continued evaluation will determine prosthetic longevity and maintained clinical improvement.
Background:
Posterior humeral decentering presents a challenge in glenohumeral arthroplasty. Soft tissue releases and osteophyte resection can lead to intraoperative decentering not evident preoperatively. Inferior outcomes result if decentering is not addressed as a part of the arthroplasty. When there is >50% posterior subluxation of the humeral head on passive elevation of the arm at surgery, we have used an anteriorly eccentric humeral head component to improve centering of the humeral articular surface on the glenoid.
Methods:
We reviewed the 2-year outcomes for 33 shoulder arthroplasties in which anteriorly eccentric humeral heads were used to manage posterior decentering identified at surgery. Rotator interval plication was performed in 16 cases as an adjunctive stabilizing procedure. Shoulders were evaluated preoperatively and postoperatively with the Simple Shoulder Test (SST). Radiographic centering was characterized before surgery and at follow-up on standardized axillary radiographs with the arm held in a position of functional elevation.
Results:
With the anteriorly eccentric head component, preoperative radiographic humeral decentering was reduced from 10.4% ± 7.9% to 0.9% ± 2.3% postoperatively (P < .001). SST scores improved from 4.8 ± 2.3 to 10.0 ± 2.3 (P < .001). Preoperative posterior humeral head decentering did not correlate with preoperative glenoid version. Glenoid retroversion was 19.8° ± 8.9° preoperatively and 15.5° ± 7.5° postoperatively.
Conclusions:
Posterior decentering identified at surgery when standard trial components are in place can be addressed by replacing the anatomic humeral head with an anteriorly eccentric humeral head component.
The use of a new augmented glenoid component has the advantages of preserving glenoid bone stock while restoring the alignment of the glenohumeral joint in anatomic total shoulder arthroplasty with severe posterior bone loss. We present the preoperative planning and surgical technique along with the early clinical and radiographic results of the first 24 cases using the DePuy Johnson and Johnson StepTech Anchor Peg Glenoid. Early results with a minimum of 6-month follow-up demonstrate excellent seating and clinical results with average active elevation of 162 degrees and postoperative PENN score of 84. Postoperative computed tomography analysis demonstrated excellent correction (mean 16.7 degrees) of glenoid version with minimal loss (mean 0.45 mm) of the premorbid joint line.
Background:
Glenoid components often cause total shoulder arthroplasty failure. This study examines short-term to midterm radiographic and clinical results of a hybrid glenoid component with 3 cemented peripheral pegs and a central peg, which allows biologic fixation with use of native humeral head autograft.
Methods:
In 4 years, 80 glenoid components were implanted during primary total shoulder arthroplasty with at least 2-year follow-up data. Within 12 months, 4 shoulders were revised and excluded from final analyses. Seven patients did not complete their questionnaires. Outcomes data included the American Shoulder and Elbow Surgeons (ASES) questionnaire, Constant score, and satisfaction score. A shoulder and elbow fellowship-trained surgeon, not involved in the care of these patients, analyzed radiographs for radiolucent lines, glenoid seating, and radiodensity in between the flanges of the central peg.
Results:
Only 1 of 80 shoulders was revised for aseptic glenoid loosening. At final follow-up, 81.6% had a radiolucency grade of 0 or 1. Nearly 90% had a glenoid seating grade of A or B. Grade 2 or 3 bone around the central peg was seen in 88.2%. No statistical association existed between Walch glenoid types and radiolucency grades, bone grades around the central peg, perfect radiolucency grade, seating grade, and grade 3 bone around the central peg. There was significant improvement in mean ASES score, adjusted ASES pain score, Constant score, and satisfaction score as well as in forward flexion, abduction, and external rotation.
Conclusions:
The hybrid glenoid can produce stable radiographic and clinical outcomes at short- to medium-term follow-up.
The Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Computerized Adaptive Test (PF CAT) is a newly developed patient-reported outcome instrument designed by the National Institutes of Health to measure generalized physical function. However, the measurement properties of the PF CAT have not been compared with established shoulder-specific patient-reported outcomes.
Patients with clinical diagnosis of rotator cuff disease completed the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST), and PF CAT. Responses to each of the 3 instruments were statistically analyzed with a Rasch partial credit model. Associations between instruments, convergent validity, item and person reliability, ceiling and floor effects, dimensionality, and survey length were determined.
Responses from 187 patients were analyzed. The PF CAT required fewer questions than the ASES or SST (PF CAT, 4.3; ASES, 11; SST, 12). Correlation between all instruments was moderately high. Item reliability was excellent for all instruments, but person reliability of the PF CAT was superior (0.93, excellent) to the SST (0.71, moderate) and ASES (0.48, fair). Ceiling effects were similar among all instruments (PF CAT, 0.53%; SST, 6.1%; ASES, 2.3%). Floor effects were found in 21% of respondents to the SST but in only 3.2% of PF CAT and 2.3% of ASES respondents.
The measurement properties of the PROMIS PF CAT compared favorably with the ASES and SST despite requiring fewer questions to complete. The PROMIS PF CAT had improved person reliability compared with the ASES score and fewer floor effects compared with the SST.
Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.
Uncorrected glenoid retroversion during total shoulder arthroplasty may lead to an increased likelihood of glenoid prosthetic loosening. Augmented glenoid components seek to correct retroversion to address posterior glenoid bone loss, but few biomechanical studies have evaluated their performance.
We compared the use of augmented glenoid components with eccentric reaming with standard glenoid components in a posterior glenoid wear model. The primary outcome for biomechanical stability in this model was assessed by (1) implant edge displacement in superior and inferior edge loading at intervals up to 100,000 cycles, with secondary outcomes including (2) implant edge load during superior and inferior translation at intervals up to 100,000 cycles, and (3) incidence of glenoid fracture during implant preparation and after cyclic loading.
A 12°-posterior glenoid defect was created in 12 composite scapulae, and the specimens were divided in two equal groups. In the posterior augment group, glenoid version was corrected to 8° and an 8°-augmented polyethylene glenoid component was placed. In the eccentric reaming group, anterior glenoid reaming was performed to neutral version and a standard polyethylene glenoid component was placed. Specimens were cyclically loaded in the superoinferior direction to 100,000 cycles. Superior and inferior glenoid edge displacements were recorded.
Surviving specimens in the posterior augment group showed greater displacement than the eccentric reaming group of superior (1.01 ± 0.02 [95% CI, 0.89-1.13] versus 0.83 ± 0.10 [95% CI, 0.72-0.94 mm]; mean difference, 0.18 mm; p = 0.025) and inferior markers (1.36 ± 0.05 [95% CI, 1.24-1.48] versus 1.20 ± 0.09 [95% CI, 1.09-1.32 mm]; mean difference, 0.16 mm; p = 0.038) during superior edge loading and greater displacement of the superior marker during inferior edge loading (1.44 ± 0.06 [95% CI, 1.28-1.59] versus 1.16 ± 0.11 [95% CI, 1.02-1.30 mm]; mean difference, 0.28 mm; p = 0.009) at 100,000 cycles. No difference was seen with the inferior marker during inferior edge loading (0.93 ± 0.15 [95% CI, 0.56-1.29] versus 0.78 ± 0.06 [95% CI, 0.70-0.85 mm]; mean difference, 0.15 mm; p = 0.079). No differences in implant edge load were seen during superior and inferior loading. There were no instances of glenoid vault fracture in either group during implant preparation; however, a greater number of specimens in the eccentric reaming group were able to achieve the final 100,000 time without catastrophic fracture than those in the posterior augment group.
When addressing posterior glenoid wear in surrogate scapula models, use of angle-backed augmented glenoid components results in accelerated implant loosening compared with neutral-version glenoid after eccentric reaming, as shown by increased implant edge displacement at analogous times.
Angle-backed components may introduce shear stress and potentially compromise stability. Additional in vitro and comparative long-term clinical followup studies are needed to further evaluate this component design.
Abnormal glenoid version positioning has been recognized as a cause of glenoid component failure caused by the rocking horse phenomenon. In contrast, the importance of the glenoid inclination has not been investigated.
The computed tomography scans of 152 healthy shoulders were evaluated. A virtual glenoid component was positioned in 2 different planes: the maximum circular plane (MCP) and the inferior circle plane (ICP). The MCP was defined by the best fitting circle of the most superior point of the glenoid and 2 points at the lower glenoid rim. The ICP was defined by the best fitting circle on the rim of the inferior quadrants. The inclination of both planes was measured as the intersection with the scapular plane. We defined the force vector of the rotator force couple and calculated the magnitude of the shear force vector on a virtual glenoid component in both planes during glenohumeral abduction.
The inclination of the component positioned in the MCP averaged 95° (range, 84°-108°) and for the ICP averaged 111° (range, 94°-126°). A significant reduction in shear forces was calculated for the glenoid component in the ICP vs the MCP: 98% reduction in 60° of abduction to 49% reduction in 90° of abduction.
Shear forces are significantly higher when the glenoid component is positioned in the MCP compared with the ICP, and this is more pronounced in early abduction. Positioning the glenoid component in the inferior circle might reduce the risk of a rocking horse phenomenon.
Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.
Introduction:
The ream and run is a technically demanding shoulder arthroplasty for the management of glenohumeral arthritis that avoids the risk of failure of the glenoid component that is associated with total shoulder arthroplasty.
Step 1 surgical approach:
After administration of prophylactic antibiotics and a thorough skin preparation, expose the glenohumeral joint through a long deltopectoral incision, incising the subscapularis tendon from its osseous insertion and the capsule from the anterior-inferior aspect of the humeral neck while carefully protecting all muscle groups and neurovascular structures.
Step 2 humeral preparation:
Gently expose the proximal part of the humerus, resect the humeral head at 45° to the orthopaedic axis while protecting the rotator cuff, and excise all humeral osteophytes.
Step 3 glenoid preparation:
After performing an extralabral capsular release, remove any residual cartilage, drill the glenoid centerline, and ream the glenoid to a single concavity.
Step 4 humeral prosthesis selection:
Select a humeral prosthesis that fits the medullary canal and that provides the desired mobility and stability of the prosthesis.
Step 5 humeral prosthesis fixation:
Fix the humeral component using impaction autografting.
Step 6 soft-tissue balancing:
After the definitive humeral prosthesis is in place, ensure the desired balance of mobility and stability. If there is excessive posterior translation, consider a rotator interval plication.
Step 7 rehabilitation:
Achieve and maintain at least 150° of flexion and good external rotation strength.
Results:
In our study, comfort and function increased progressively after the ream-and-run procedure, reaching a steady state by approximately twenty months.
What to watch for:
IndicationsContraindicationsPitfalls & Challenges.
Glenoid bone loss associated with advanced glenohumeral arthritis is frequently accompanied by subluxation of the humeral head with subsequent inferior outcomes of shoulder arthroplasty. We hypothesized that the relationship between the center of the humeral head and the perpendicular to the glenoid fossa plane differs from, and is independent of, the relationship between the center of the humeral head and the plane of the scapula.
Three-dimensional computed tomography (3D CT) imaging was performed on sixty patients with advanced osteoarthritis and fifteen controls with no osteoarthritis to define the baseline relationship between the center of the humeral head and the perpendicular to the glenoid fossa plane and the plane of the scapula. Correlations between these variables and the amount of bone loss and glenoid version were assessed.
There was a strong linear relationship (p < 0.001) between glenoid retroversion and the center of the humeral head in relation to the center line of the scapula (humeral-scapular alignment). Humeral head alignment in relation to the glenoid plane (humeral-glenoid alignment) was variable and not strongly correlated with the amount of glenoid retroversion. The average glenoid retroversion for the normal shoulders was -3.5°, and the average humeral-scapular alignment offset percentage was -2.3%. The average humeral-glenoid alignment offset for the normal shoulders was 0.5 mm with an average humeral-glenoid alignment offset percentage of 0.9%.
The location of the humeral head in relation to the glenoid can be defined as displacement from the plane of the scapula and from the perpendicular of the glenoid plane. These two measures are independent of one another. The data suggest that each measurement may represent a different effect on glenoid loading.
The importance of this study is that it presents quantitative data and clear guidelines to define two measurements of glenohumeral alignment as separate and important variables. The clinical relevance of these methods will be further defined when they are correlated with clinical outcomes.
Background
The glenoid vault can be perforated during pegged glenoid preparation in total shoulder arthroplasty. The clinical implications of glenoid vault perforation, however, are unknown. The purpose of this study was to determine the effects of perforation of the glenoid during total shoulder arthroplasty on clinical and radiographic outcomes.
Materials and methods
Eighteen patients with known intraoperative glenoid perforations were prospectively identified and compared with 34 patients matched by age, gender, diagnosis, and arm dominance during the same period. Patients were evaluated with multiple outcome scores. Radiographs were evaluated for glenoid lucency immediately postoperatively and at final follow-up.
Results
Average follow-up was 28.1 months for the perforated group and 31.2 months for the matched controls. Both groups had significant improvements in outcome scores postoperatively. American Shoulder and Elbow Surgeons scores increased from 39.8 to 91.0 (P < .001) in the perforated group and from 36.9 to 82.6 (P < .001) in the control group. Constant scores increased from 24.4 to 77.4 (P < .001) in the perforated group and from 36.9 to 75.6 (P < .001) in the control group. Ninety-four percent of the perforated group and 80% of the matched controls were satisfied or very satisfied with their result (P = .896). The presence and number of perforations were not related to the American Shoulder and Elbow Surgeons score (P = .549), Constant score (P = .154), or radiographic lucency grade (P = .584).
Conclusions
Glenoid perforation during pegged glenoid preparation in total shoulder arthroplasty does not seem to have an adverse effect on clinical or radiographic outcomes at an average of 2 years of follow-up.
The magnitude and anatomic consequences of pathologic acquired glenoid retroversion and posterior bone loss that can be surgically corrected with a standard versus an augmented glenoid component have not been studied extensively in a surgical patient population.
Twenty-nine patients with glenohumeral osteoarthritis, acquired posterior bone loss, and increased retroversion were studied by use of a three-dimensional computer surgical simulation. For each case, amount of medialization was measured as the linear distance from the lateral aspect of the glenoid vault model to the center of the articular implant surface. Simulation of implant placement at 0° or 6° was performed with use of a standard glenoid having a uniform thickness and an asymmetric thickness augmented component.
An increased amount of medialization was seen with the standard glenoid, 8.3 ± 4.1 mm, compared with 3.8 ± 3.3 mm with use of the augmented glenoid implant (P < .001). When glenoid retroversion was corrected to 0°, pathologic version was shown to have strong and significant relationship to the amount of medialization for both the standard (R(2) = 0.825) and augmented (R(2) = -0.68) glenoid implant. There was an increased ability to correct greater amounts of pathologic version with less medialization by use of an augmented step glenoid compared with a standard anchor peg glenoid.
Correction of moderate to severe glenoid retroversion by asymmetric reaming cannot always be done with use of a standard component, and if it is done, it will result in greater medialization of the joint line. Use of an augmented component can allow complete correction of retroversion and minimize the effect of medialization.
Osteoarthritis results in changes in the dimensions of the glenoid. This study aimed to assess the size and radius of curvature of arthritic glenoids. A total of 145 CT scans were analysed, performed as part of routine pre-operative assessment before total shoulder replacement in 91 women and 54 men. Only patients with primary osteoarthritis and a concentric glenoid were included in the study. The CT scans underwent three-dimensional (3D) reconstruction and were analysed using dedicated computer software. The measurements consisted of maximum superoinferior height, anteroposterior width and a best-fit sphere radius of curvature of the glenoid.
The mean height was 40.2 mm (sd 4.9), the mean width was 29 mm (sd 4.3) and the mean radius of curvature was 35.4 mm (sd 7.8). The measurements were statistically different in men and women and had a Gaussian distribution with marked variation. All measurements were greater than the known values in normal subjects.
With current shoulder replacement systems using a unique backside radius of curvature for the glenoid component, there is a risk of undertaking excessive reaming to adapt the bone to the component resulting in sacrifice of subchondral bone or under-reaming and instability of the component due to a ’rocking horse‘ phenomenon.
Cite this article: Bone Joint J 2013;95-B:1377–82.
Glenoid morphology has an important impact on outcomes and complication rates after shoulder arthroplasty for primary glenohumeral arthritis. The B2 glenoid, or a biconcave glenoid with posterior humeral head subluxation, in particular has been associated with a poorer outcome with shoulder arthroplasty compared with other glenoid types. A variety of techniques may be used to address the bone deficiency and instability seen with this glenoid type. Studies suggest that total shoulder arthroplasty may have a reasonable result in the short term but be associated with a high complication rate in the mid term because of recurrence of instability and early glenoid loosening when neoglenoid retroversion is greater than 27° or posterior humeral head subluxation is greater than 80%. Particularly in older patients with a substantial B2 deformity, primary reverse shoulder arthroplasty may be a more predictable means of addressing bone deficiency and restoring stability.
The biconcave glenoid in patients with primary glenohumeral osteoarthritis represents a surgical challenge because of the associated static posterior instability of the humeral head and secondary posterior glenoid erosion. The purpose of the present study was to evaluate the clinical and radiographic results of reverse total shoulder arthroplasty for the treatment of primary osteoarthritis in patients with a biconcave glenoid without rotator cuff insufficiency.
We performed a retrospective review of twenty-seven reverse shoulder arthroplasties that were performed from 1998 to 2009 for the treatment of primary glenohumeral osteoarthritis and biconcave glenoid. Eighty-one percent of the patients were female, and the mean age of the patients at the time of surgery was 74.1 years (range, sixty-six to eighty-two years). All patients had a preoperative computed tomography arthrogram to allow for the measurement of glenoid retroversion and humeral head subluxation. The mean preoperative retroversion was 32°, and the mean subluxation of the humeral head with respect to the scapular axis was 87%. Seventeen patients had a reverse shoulder arthroplasty without bone graft, whereas ten had an associated bone graft to compensate for posterior glenoid erosion. Clinical outcomes were evaluated with the Constant score and shoulder range of motion.
The mean duration of follow-up was fifty-four months (range, twenty-four to 139 months). The mean Constant score increased from 31 points preoperatively to 76 points at the time of the latest follow-up (p < 0.0001). Active forward flexion, external rotation, and internal rotation also significantly increased (p < 0.0001). Complications occurred in four patients (15%) and included early loosening of the glenoid component (one patient) and neurologic complications (three patients). No radiolucent lines were observed around the central peg or screws of the glenoid component. Grade-1 or 2 scapular notching was present in ten shoulders (37%). No recurrence of posterior instability was observed.
Reverse shoulder arthroplasty for the treatment of primary glenohumeral osteoarthritis in patients with a biconcave glenoid without rotator cuff insufficiency can result in excellent clinical outcomes. Reverse shoulder arthroplasty is a viable surgical option to solve both the problem of severe static posterior glenohumeral instability and severe glenoid erosion.
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Glenohumeral osteoarthritis may be associated with severe posterior glenoid bone loss and glenoid retroversion. Treatment with total shoulder arthroplasty and autologous bone graft obtained from the humeral head has been infrequently reported in the peer-reviewed literature.
The clinical and radiographic results of primary total shoulder replacement with an all-polyethylene glenoid component and autologous humeral head graft augmentation performed by a single surgeon in thirteen consecutive patients were evaluated.
Twelve of the thirteen patients were followed for a minimum of two years (average, fifty-three months; range, twenty-six to 110 months). The average glenoid retroversion on preoperative computed tomography (CT) scans was 44° (range, 20° to 65°). Based on the Walch classification of pathologic glenoid morphology, nine glenoids were B2 and three were type C. All patients had an intact cuff at the time of surgery. At the time of the last follow up, ten of the twelve patients had graft incorporation without any resorbtion and two had minor bone graft resorption. Broken screws occurred in two of these ten cases. Two patients, both of whom required revision surgery, had failure of fixation and of graft incorporation; one of these failures was due to early postoperative trauma and the other, to Propionibacterium acnes infection.
The early and midterm results of total shoulder arthroplasty with autogenous bone graft demonstrated substantial clinical and radiographic improvement in most cases.
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Glenoid bone deficiency and eccentric posterior wear are difficult problems faced by shoulder arthroplasty surgeons. Numerous options and techniques exist for addressing these issues. Hemiarthroplasty with concentric glenoid reaming may be a viable alternative in motivated patients in whom glenoid component failure is a concern. Total shoulder arthroplasty has been shown to provide durable pain relief and excellent function in patients, and numerous methods and techniques can assist in addressing bone loss and eccentric wear. However, the ideal amount of version correction in cases of severe retroversion has not yet been established. Asymmetric reaming is a commonly used technique to address glenoid version, but correction of severe retroversion may compromise bone stock and component fixation. Bone grafting is a technically demanding alternative for uncontained defects and has mixed clinical results. Specialized glenoid implants with posterior augmentation have been created to assist the surgeon in correcting glenoid version without compromising bone stock, but clinical data on these implants are still pending. Custom implants or instruments based on each patient's unique glenoid anatomy may hold promise. In elderly, sedentary patients in whom bone stock and soft-tissue balance are concerns, reverse total shoulder arthroplasty may be less technically demanding while still providing satisfactory pain relief and functional improvements.
Background:
It has been suggested that glenoid component retroversion and eccentric loading are an important mechanism leading to glenoid component loosening, but little clinical data have been published to support this concept.
Methods:
Sixty-six shoulders underwent total shoulder replacement with an all-polyethylene press-fit pegged glenoid component designed for osseous ingrowth for treatment of osteoarthritis. These shoulders were followed clinically and with radiographs for an average (and standard deviation) of 3.8 ± 1.8 years (range, two to seven years). Preclinical radiographic loosening was defined as osteolysis around the central peg of the glenoid component.
Results:
Of the sixty-six shoulders, twenty (30%) had osteolysis around the center peg. The length of time after replacement (p = 0.0006), preoperative glenoid retroversion (p = 0.036), and postoperative glenoid component retroversion (p = 0.041) were correlated with osteolysis around the glenoid center peg and an increase in the Lazarus component loosening grade. Postoperative retroversion correlated with preoperative retroversion (Pearson correlation coefficient = 0.44, 95% confidence interval [CI] = 0.19 to 0.64, p = 0.0011). The presence of osteolysis around the center peg was not correlated with a worse clinical outcome defined by shoulder scores or a reoperation due to glenoid loosening. After adjustment for follow-up time, excessive postoperative glenoid retroversion (≥15°) was associated with an increased odds of osteolysis (odds ratio = 5.23, 95% CI = 1.31 to 20.9]), whereas preoperative glenoid retroversion was associated with no change in the odds of osteolysis.
Conclusions:
Osteolysis around the center peg of a glenoid component is correlated with component retroversion of ≥15°. This finding suggests that there should be additional investigation into the effects of correcting preoperative glenoid retroversion to prevent osteolysis around the center peg.
Background:
Radiographic imaging is the follow-up imaging modality most widely used for patients who have undergone total shoulder arthroplasty (TSA). However, its accuracy of measurement of component position has not been validated against a gold standard in a clinical series.
Methods:
Thirty-two x-ray images and computed tomography scans were taken within 1 month of each other in patients who had undergone TSA with an all-polyethylene glenoid component. The humeral glenoid alignment in the coronal superior-inferior (SI) plane (HGA-SI), humeral glenoid alignment in the axial anterior-posterior (AP) plane (HGA-AP), and humeral scapular alignment in the axial plane (HSA-AP) were measured with 21 pairs of images, and glenoid component retroversion was measured with all 32 pairs. Intraclass correlation coefficients (ICC) were calculated for HGA-SI, HGA-AP, HSA-AP, and version, and accuracy analysis criteria of the radiographs were assessed using predetermined criterion.
Results:
We found fair-moderate agreement between x-ray images and CT scans for HGA-SI (ICC = 0.42) and version (ICC = 0.69), but poor agreement for HGA-AP (ICC = 0.04) and HSA-AP (ICC = 0.38). An average difference of overestimating HGA-SI by 0.06% ± 7.7%, with a precision 95% confidence interval of 7.6%, and overestimating version by -4.2° ± 5.1°, with a precision 95% confidence interval of 9.9°, was found.
Conclusion:
This validation study has defined the ability and limitation for these measurements using high-quality axillary and AP radiographs.
Glenohumeral osteoarthritis is the most common reason for shoulder replacement. Total shoulder arthroplasty provides reliable pain relief and restoration of function, with implant survivorship reported at 85% at 15 years. Glenoid component wear and aseptic loosening are among the most common reasons for revision. Glenoid wear characteristics have been correlated with, among other things, the degree of anatomic glenoid version correction. Anatomic glenoid reconstruction is particularly challenging in the presence of glenoid bone deficiency. Walch classified glenoid morphology into five types: type A, centered, without posterior subluxation but with minor erosion (A1) or major erosion (A2); type B, posteriorly subluxated (B1) or posteriorly subluxated with posterior glenoid erosion (B2); and type C, excessive glenoid retroversion. The type A glenoid represents only 59% of patients; thus, the need to address glenoid deformity is common. Methods of correction include asymmetric reaming of the anterior glenoid, bone grafting of the posterior glenoid, and implanting a specialized glenoid component with posterior augmentation. In many cases of type C or hypoplastic glenoid, the humerus is concentrically reduced in the deficient glenoid and glenoid deformity may not need to be corrected. Severely hypoplastic glenoid may require the use of bone-sparing glenoid components or reverse total shoulder arthroplasty.
Knowledge of the factors affecting the prognosis for improvement in function and comfort with time after shoulder arthroplasty is important to clinical decision-making. This study sought to identify some of these factors in 176 consecutive patients undergoing the ream-and-run procedure.
The time course for improvement in patient function and comfort was determined for the entire group as well as for subsets by sex, age, diagnosis, preoperative function, and surgery date. Patients having repeat surgery were analyzed in detail.
Shoulder comfort and function increased progressively after the ream-and-run procedure, reaching a steady state by approximately twenty months. The shoulders in 124 patients with at least two years of follow-up were improved by a minimal clinically important difference. The shoulders in sixteen patients with at least two years of follow-up were not improved by the minimal clinically important difference. Twenty-two patients had repeat procedures, but only seven had revision to a total shoulder arthroplasty. Fourteen patients did not have either a known revision arthroplasty or two years of follow-up. The best prognosis was for male patients over the age of sixty years, with primary osteoarthritis, no prior surgical procedures, a preoperative score on the simple shoulder test of ≥5 points, and surgery after 2004. Repeat surgical procedures were more common in patients who had a greater number of surgical procedures before the ream-and-run surgery.
This study is unique in that it characterizes the factors affecting the time course for improvement in shoulder comfort and function after a ream-and-run procedure. Improvement occurs after this procedure for at least 1.5 years. This procedure appears to be best suited for an older male patient with reasonable preoperative shoulder function without prior shoulder surgery.
Prognostic Level II. See Instructions for authors for a complete description of levels of evidence.
Biconcave glenoids in primary osteoarthritis represent a challenge because of the associated static posterior instability of the humeral head and secondary posterior glenoid erosion. This study evaluated the influence of different preoperative radiographic measurements on the outcome of total shoulder arthroplasty (TSA), particularly regarding the development of complications.
We retrospectively evaluated 92 anatomic TSAs performed in 75 patients with primary osteoarthritis and a biconcave glenoid. All patients underwent preoperative imaging with an axial computed tomography arthrogram. Measurements were taken for posterior bone erosion depth and ratio as well as humeral head subluxation. Clinical outcomes were evaluated with the Constant score.
At an average follow up of 77 months (range, 14-180 months), 15 revisions (16.3%) were performed for glenoid loosening (6.5%), posterior instability (5.5%), or soft tissue problems (4.3%). At the final follow-up, the mean Constant score improved significantly from 32.4 to 68.8 points (P = .0001). Subjectively, 66.3% of patients were very satisfied or satisfied. Glenoid loosening was observed in 20.6% and was significantly associated with posterior bone erosion in depth (P = .005) and wear ratio (P = .02), humeral head subluxation (P = .01), and neoglenoid (P = .002) and intermediate glenoid retroversion (P = .001). Dislocation was correlated only with neoglenoid retroversion (P = .01).
Performing TSA in patients with osteoarthritis and biconcave glenoids resulted in acceptable clinical outcomes but a very high rate of complications. We found that the preoperative measurement of the neoglenoid retroversion was best for predicting postoperative complications in terms of glenoid loosening and dislocation.
Loosening of the glenoid component continues to be the foremost cause of medium and long-term failure of shoulder replacements. The purpose of this study was to evaluate the clinical and radiographic results of a minimally cemented all-polyethylene pegged glenoid component designed for biologic fixation.
Forty-four shoulders in forty-one patients with a mean age of sixty-six years underwent total shoulder arthroplasty with a pegged bone-ingrowth glenoid component. Outcome data included the American Shoulder and Elbow Surgeons questionnaire, the Simple Shoulder Test, and visual analog scales. A detailed radiographic analysis was performed by two board-certified musculoskeletal radiologists who were blinded to clinical and patient-reported outcomes. The radiographs were evaluated with regard to the presence of radiolucent lines at the bone-cement interface, implant seating, and the radiodensity between the flanges of the central peg.
The mean duration of clinical follow-up was four years and the mean duration of radiographic follow-up was three years. Twenty shoulders had perfect seating and radiolucency grades, thirty had increased radiodensity between the flanges of the central peg, and three demonstrated osteolysis. Radiodensity about the uncemented central peg at the time of the latest follow-up was positively associated with perfect seating and radiolucency grades on the initial postoperative radiographs (p = 0.03, Fisher exact test). The Simple Shoulder Test score, the American Shoulder and Elbow Surgeons score, and all visual analog scale scores had improved significantly (p < 0.01) at the time of the latest follow-up.
Total shoulder arthroplasty with a minimally cemented, all-polyethylene, pegged glenoid implant can yield stable and durable fixation at short to medium-term follow-up (mean, four years).
The aim of this study was to radiographically analyze the long-term glenoid migration patterns following total shoulder arthroplasty to better understand the factors responsible for loosening.
Complete radiographic follow-up of more than five years was available for 518 total shoulder arthroplasties performed for primary glenohumeral osteoarthritis with use of an anatomically designed prosthesis with a cemented, all-polyethylene, keeled glenoid component. Radiographs were assessed for humeral head subluxation, periprosthetic radiolucent lines, and shifting of the position of the glenoid component. The type of migration of the glenoid was defined according to the direction of tilt, or as subsidence in the case of medial migration.
Definite radiographic evidence of glenoid loosening was observed in 166 shoulders (32%) and was characterized by radiolucency of ≥2 mm over the entire bone-cement interface in thirty shoulders and by a migration of the glenoid component (shift or subsidence) in 136 shoulders. Three predominant patterns of migration of the glenoid component were observed: superior tilting in fifty-two shoulders (10%), subsidence in forty-one shoulders (7.9%), and posterior tilting in thirty-three shoulders (6.4%). Superior tilting of the glenoid was associated with three risk factors: low positioning of the glenoid component, superior tilt of the glenoid component on the immediate postoperative coronal plane radiographs, and superior subluxation of the humeral head (p < 0.05 for all). Subsidence of the glenoid component was associated with the use of reaming to optimize the seating and positioning of the glenoid component (p < 0.001). Posterior tilting of the glenoid component was associated with preoperative posterior subluxation (i.e., a Walch type-B glenoid) and with excessive reaming (p < 0.01 for both).
The three patterns of migration observed in this study underscore the potential importance of the supporting bone beneath the glenoid component. In some shoulders, use of a keel or pegs to provide fixation of a polyethylene component in the absence of good support from subchondral bone may not be sufficient to resist compressive and eccentric forces, resulting in loosening. Preserving subchondral bone may be important for long-term longevity of the glenoid component.
The Simple Shoulder Test (SST) is an internationally used patient-reported outcome for clinical practice and research purposes. It was developed for measuring functional limitations of the affected shoulder in patients with shoulder dysfunction and contains 12 questions (yes/no). The purpose of this study was to create a Dutch translation of the SST and to assess the reliability and validity.
The SST was translated into Dutch using forward and backward translations. A consecutive cohort of patients with shoulder problems visiting an orthopedic clinic completed the Dutch version of the SST twice within 28 days. In addition, the Dutch validated versions of the Disabilities of the Arm, Shoulder and Hand, Oxford Shoulder Score, and Constant-Murley shoulder assessment were completed for assessing construct validity.
One hundred ten patients with a mean age of 39 years (SD, 14 years), 72% male, completed the questionnaires. The internal consistency was high (Cronbach α, 0.78). The test-retest reliability was very good (intraclass correlation coefficient, 0.92) (n = 55). The measurement error expressed in the standard error of measurement was 1.18, and the smallest detectable change was 3.3 on a scale from 0 to 12. The construct validity was supported by expected high correlations between the Dutch version of the SST and the Disabilities of the Arm, Shoulder and Hand (r = -0.74) and between the SST and the Oxford Shoulder Score (r = -0.74) and an expected moderate correlation between the SST and the Constant-Murley shoulder assessment (r = 0.59).
The Dutch version of the SST seems to be a reliable and valid instrument for evaluating functional limitations in patients with shoulder complaints.
Aseptic glenoid component loosening remains a common problem in total shoulder arthroplasty (TSA). This study presents long-term prospective follow-up of 2 cemented all-polyethylene glenoid components with different backside design geometry and the effect on the presence and progression of radiolucent lines (RLLs).
Fifty-six TSAs were performed for primary osteoarthritis. Two surgeons used an identical technique to implant 32 flat-back and 24 convex-back glenoids. In particular, the glenoid components were cemented after a minimal reaming and bone compaction. Standardized postoperative radiologic and clinical follow-up was at 2 and 10 years. Three independent observers evaluated the x-ray images for RLLs around the base plate and keel. The results were analyzed for progression and influencing factors.
At 10 years, progression of RLL was seen in both components, but there was no difference between the 2 glenoid designs (P = .16). Younger patient age (P = .03), hand dominance (P = .017), and presence of early RLLs (P = .018) were significant factors for progression of RLLs. Constant scores deteriorated with progression of RLLs (P = .006). The glenoid revision rate at 10 years was 5%.
At 10 years there was no difference in the presence or progression of RRLs between a flat-back and a convex-back glenoid all-polyethylene design. Young age, hand dominance, and poor implantation technique influence glenoid RLLs and affect the clinical result of TSA.
The optimal degree of conformity between the glenoid and humeral components in total shoulder arthroplasty for best performance and durability is still a matter of debate. The main aim of this study is to evaluate the influence of joint conformity on the bone-implant interface micromotions in a cementless glenoid implant.
Polyethylene inlays with different degrees of conformity (radial mismatch of 0, 2, 4, and 6 mm) were mounted on a cementless metal back and then implanted in a bone substitute. These glenoid components were loaded by a prosthetic humeral head during a force-controlled experiment. Normal-to-interface micromotions and bone substitute deformations were measured at different points of the interface. Rim displacement and humeral head translation were also measured. A finite element (FE) model of the experiments was implemented to estimate the normal- and tangent-to-interface micromotions in the entire bone-implant interface.
All measured variables increased with less-conforming PE inlays. Normal-to-interface micromotions were significantly larger (P < .05) when the radial mismatch was 6 mm compared with the fully conforming inlay. The FE model was in agreement and complemented the experimental results. FE model-predicted interface micromotions were already significantly larger when the radial mismatch was equal to 4 mm.
In a force-controlled experiment with a cementless glenoid component, a non-conforming PE inlay allows larger interface micromotions than a conforming inlay, reaching a magnitude that may hamper local bone ingrowth in this type of component. This is mainly because of the larger humeral head translation that boosts the effects of the so-called rocking-horse phenomenon.
We report the long-term clinical and radiological outcomes of the Aequalis total shoulder replacement with a cemented all-polyethylene flat-back keeled glenoid component implanted for primary osteoarthritis between 1991 and 2003 in nine European centres. A total of 226 shoulders in 210 patients were retrospectively reviewed at a mean of 122.7 months (61 to 219) or at revision. Clinical outcome was assessed using the Constant score, patient satisfaction score and range of movement. Kaplan-Meier survivorship analysis was performed with glenoid revision for loosening and radiological glenoid loosening (sd) as endpoints. The Constant score was found to improve from a mean of 26.8 (sd 10.3) pre-operatively to 57.6 (sd 20.0) post-operatively (p < 0.001). Active forward flexion improved from a mean of 85.3° (sd 27.4) pre-operatively to 125° (sd 37.3) postoperatively (p < 0.001). External rotation improved from a mean of 7° (sd 6.5) pre-operatively to 30.3° (sd 21.8°) post-operatively (p < 0.001). Survivorship with revision of the glenoid component as the endpoint was 99.1% at five years, 94.5% at ten years and 79.4% at 15 years. Survivorship with radiological loosening as the endpoint was 99.1% at five years, 80.3% at ten years and 33.6% at 15 years.
Younger patient age and the curettage technique for glenoid preparation correlated with loosening. The rate of glenoid revision and radiological loosening increased with duration of follow-up, but not until a follow-up of five years. Therefore, we recommend that future studies reporting radiological outcomes of new glenoid designs should report follow-up of at least five to ten years.
Prospective cohort study with repeated measures.
To establish the responsiveness of the Simple Shoulder Test (SST) in comparison to other commonly used clinical outcomes in patients undergoing shoulder arthroplasty.
Responsiveness statistics are a useful means to compare different outcomes in terms of their ability to detect clinical change. While the responsiveness of the SST has been established for rotator cuff repair, it has not been determined for patients undergoing arthroplasty.
Patients undergoing shoulder arthroplasty (n=120) were evaluated prior to surgery and 6 months after. The evaluation included the SST, Disabilities of the Arm, Shoulder and Hand questionnaire, range of motion, and isometric strength. Responsiveness to change was assessed using standardized response mean (SRM), while longitudinal construct validity was evaluated using Pearson correlation. Receiver operating characteristics curves were plotted to determine clinically important difference of SST.
The SST and Disabilities of the Arm, Shoulder and Hand questionnaire were highly responsive (SRM, >1.70) for this population. For the assessment of impairment, range of motion (SRM, 0.64-1.03) was moderately to highly responsive, while isometric strength was minimally to moderately responsive (SRM, 0.32-0.69). The clinically important difference of the SST was established at 3.0 SST points. Pearson correlations indicated moderate associations between the change scores of the SST and the Disabilities of the Arm, Shoulder and Hand questionnaire (r=0.49).
The SST has been previously shown to be valid and highly reliable. The present results show that the SST is also responsive following shoulder arthroplasty and that it has a clinically important difference of 3.0 SST points. This should provide confidence to clinicians who wish to use a brief shoulder-specific measure in their practice.
We have investigated the mid-term outcome of total shoulder replacement using a keeled cemented glenoid component and a modern cementing technique with regard to the causes of failure and loosening of the components.
Between 1997 and 2003 we performed 96 total shoulder replacements on 88 patients, 24 men and 64 women with a mean age of 69.7 years (31 to 82). The minimum follow-up was five years and at the time of review 87 shoulders (77 patients) were examined at a mean follow-up of 89.1 months (60 to 127). Cumulative survival curves were generated with re-operations (accomplished and planned), survivorship of the proshesis, loosening of the glenoid (defined as tilt > 5° or subsidence > 5 mm), the presence of radiolucent lines and a Constant score of < 30 as the endpoints.
There were two re-operations not involving revision of the implants and the survival rate of the prosthesis was 100.0% for the follow-up period, with an absolute Constant score of > 30 as the endpoint the survival rate was 98%. Radiological glenoid loosening was 9% after five years, and 33% after nine years. There was an incidence of 8% of radiolucent lines in more than three of six zones in the immediate post-operative period, of 37.0% after the first year which increased to 87.0% after nine years. There was no correlation between the score of Boileau and the total Constant score at the latest follow-up, but there was correlation between glenoid loosening and pain (p = 0.001).
We found that total shoulder replacement had an excellent mid-term survivorship and clinical outcome. The surgical and cementing techniques were related to the decrease in radiolucent lines around the glenoid compared with earlier studies. One concern, however, was the fact that radiolucent lines increased over time and there was a rate of glenoid loosening of 9% after five years and 33% after nine years. This suggests that the design of the glenoid component, and the implantation and cementing techniques may need further improvement.
The minimal clinically important difference is the smallest difference in an outcome score that a patient perceives as beneficial. The purpose of this study was to determine the minimal clinically important difference in the American Shoulder and Elbow Surgeons (ASES) score and in the Simple Shoulder Test (SST) score for patients treated nonoperatively for rotator cuff disease.
Eighty-one patients with tendinitis or a tear of the rotator cuff were treated with nonoperative modalities. Evaluation with the ASES score and the SST was performed at baseline and at a minimum of six weeks after treatment. At the follow-up evaluation, the minimal clinically important difference was estimated for the two scores with use of an anchor-based approach involving fifteen-item (pain and function) and four-item improvement questions.
The fifteen-item function and four-item assessments indicated, respectively, that a 2.05-point (p = 0.02) and 2.33-point (p = 0.0009) change in the SST score from baseline represented a minimal clinically important difference. The fifteen-item function, fifteen-item pain, and four-item assessments indicated that a 12.01-point (p = 0.03), 16.92-point (p = 0.004), and 16.72-point (p < 0.0001) change in the ASES score from baseline represented a minimal clinically important difference. Age, sex, initial baseline scores, and hand dominance had no effect on the minimal clinically important differences (p > 0.05). A longer duration of follow-up after treatment was associated with a greater minimal clinically important difference in the ASES score (p < 0.05), although the duration of follow-up had no effect on the minimal clinically important difference in the SST score.
Patients with rotator cuff disease who are treated without surgery and have a 2-point change in the SST score or a 12 to 17-point change in the ASES score experience a clinically important change in self-assessed outcome. These minimal clinically important differences can provide the basis for determining if significant differences in outcomes after treatment are clinically relevant.
Static posterior subluxation of the humeral head (PSH) is often associated with glenohumeral arthritis. It may persist following total shoulder arthroplasty (TSA) and lead to accelerated polyethylene wear and glenoid component loosening. The factors which lead to PSH are poorly understood. The purpose of this study was to test the hypothesis that operative correction of glenoid version during shoulder arthroplasty re-centers the glenohumeral joint; therefore, glenoid replacement may be considered even in cases of osteoarthritis associated with posterior humeral head subluxation.
Thirty-three of 124 (27%) consecutive shoulders undergoing primary TSA had static preoperative PSH with a subluxation index of at least 65% determined on standardized computer tomographic scans. Twenty-three of these 33 shoulders were available for clinical and computed tomography follow-up after a minimum of 24 and average of 42 months. Mean preoperative glenoid retroversion was -18 [range, 0 degrees - (-40 degrees)], the subluxation index averaged 71% (range, 65-81%). Glenoid morphology, according to Walch et al, was type B1 in 9 patients, type B2 in 5 patients, and type C in 9 patients. A conventional total shoulder replacement was performed through a deltopectoral interval. Using corrective glenoid reaming, restoration of glenoid version to between 0 degrees and 10 degrees of retroversion was attempted in addition to standard soft tissue release. Humeral head retroversion was replicated from the diseased humeral head as closely as possible.
PSH was reversed in 21/23 patients following TSA with an average final subluxation index of 50% (range, 40-68%; P = .001). There was no significant correlation statistically between PSH and preoperative or postoperative glenoid version, humeral torsion, glenoid morphology, or acromio-humeral distance. Mean absolute Constant scores improved from 39 to 78 points, age-adjusted Constant scores improved from 49% to 95% and subjective shoulder values improved from 40% to 89%, which were all statistically significant (P < .0001).
PSH is frequently present in shoulders with osteoarthritis. It can be corrected in the majority of shoulders undergoing total shoulder replacement; however, re-centering is not correlated with glenoid version or its correction.
Level 4; Case series, treatment study.
The purpose of this study was to characterize the role of the capsule in the interval between the supraspinatus and subscapularis tendons with respect to glenohumeral motion, translation, and stability. We used a six-degrees-of-freedom position-sensor and a six-degrees-of-freedom force and torque-transducer to determine the glenohumoral rotations and translations that resulted from applied loads in eight cadaver shoulders. The range of motion of each specimen was measured with the capsule in the rotator interval in a normal state, after the capsule had been sectioned, and after it had been imbricated. Operative alteration of this capsular interval was found to affect flexion, extension, external rotation, and adduction of the humerus with respect to the scapula. Modification of this portion of the capsule also affected obligate anterior translation of the humeral head on the glenoid during flexion. Limitation of motion and obligate translation were increased by operative imbrication and diminished by sectioning of the rotator interval capsule. Passive stability of the glenohumeral joint was evaluated with the use of anterior, posterior, and inferior stress tests. Instability and occasional frank dislocation of the glenohumeral joint occurred inferiorly and posteriorly after section of the rotator interval capsule. Imbrication of this part of the capsule increased the resistance to inferior and posterior translation.
Abnormal glenoid architecture resulting from loss of bone usually is listed among the contraindications to total shoulder arthroplasty using an unconstrained prosthesis. However, in a series of 463 consecutive replacement procedures that were performed between 1973 and 1985, in only two patients did the lack of bone make the implantation of a glenoid component impossible. Of the remaining sixty-five shoulders that had an abnormal glenoid, twenty were successfully treated with a large, internally fixed bone graft or grafts and forty-five, with smaller bone grafts that were not internally fixed. Nineteen of the twenty shoulders that had a large graft or grafts were followed for two years or more (average, 4.4 years). The clinical results were judged to be excellent in sixteen and satisfactory in one, and the desired limited goals were obtained in two. Two fixation screws broke and one screw was worn by contact with the humeral component. None of the glenoid components clinically loosened or migrated, and no patient has needed further surgical treatment. Although bone-grafting was necessary in only twenty (4.3 per cent) of the 463 replacement procedures, this procedure provided sufficient osseous support to allow implantation of a component in a severely damaged glenoid.
One hundred and fifty-one cases of primary glenohumeral osteoarthritis were analyzed both clinically and radiographically with CT scanning. There were 76% females in this series, and the mean age at operation was 66.8 years. The diagnosis was made only with true anteroposterior views of the shoulder which show the narrowing of the glenohumeral joint and the presence of osteophytes. The arthrogram showed a supra-spinatus tear in 10% of the cases that extended to the infra-spinatus in 2.6%. Glenoid retroversion averaged 15.4 degrees. However, measurements of glenoid retroversion with CT-scan do not distinguish posterior wear from glenoid dysplasia. Posterior subluxation of the humeral head was observed in 45% of the cases. We describe a classification of the glenoid morphology in three types: Type A (53.5%) is characterized by an equal balance of forces acting on the glenoid and a centralized humeral head. Type B (39.5%) has asymmetrical posterior force distribution on the glenoid and a posterior subluxation of the humeral head. Type C (5%) is arbitrarily defined as glenoid retroversion greater than 25 degrees. Posterior subluxation of the proximal humeral head did not correlate with either glenoid retroversion or humeral retroversion. However, subluxation of the humeral head may be responsible for the posterior glenoid erosion and possibly for the biconcave appearance of the glenoid observed in primary glenohumeral osteoarthritis. The posterior subluxation of the humeral head may still be present after shoulder arthroplasty and may be responsible for glenoid loosening due to a "horizontal rocking-horse effect".