The Orthopaedic Journal of Sports Medicine

Background: Bio-enhanced ACL repair, where the suture repair is supplemented with a biological scaffold, is a promising novel technique to stimulate healing after ACL rupture. However, the histological properties of a successfully healing ACL and how they relate to the mechanical properties have not been fully described. Hypothesis/purpose: The purpose of the study was to determine which histological features best correlated with the mechanical properties of the healing ACL repairs and ACL grafts in a porcine model at six and twelve months after injury. Study design: Controlled laboratory study. Methods: Forty-eight Yucatan mini-pigs underwent ACL transection followed by: 1) conventional ACL reconstruction with bone-patellar tendon-bone (BPTB) allograft, 2) bio-enhanced ACL reconstruction with BPTB allograft using a bioactive scaffold, or 3) bio-enhanced ACL repair using the same bioactive scaffold. After 6 and 12 months of healing, structural properties of the ACL or graft (yield & failure load, linear stiffness) were measured. Following mechanical testing, ACL specimens were histologically analyzed for cell and vascular density and qualitatively assessed using the advanced Ligament Maturity Index. Results: We found that after six months of healing, the cellular organization sub-score was most predictive of yield load (r(2)=0.98), maximum load (r(2)=0.89) and linear stiffness (r(2)=0.95) of the healing ACL, while at 12 months, the collagen sub-score (r(2)=0.68) became the best predictor of maximum load. For ACL grafts, the reverse was true, with the collagen sub-score predictive of yield and maximum loads at six months (r(2)=0.55), and graft cellularity predictive of maximum load of the graft at 12 months (r(2)=0.50). Conclusions: These findings suggest there may be key biologic differences in development and maintenance of ACL tissue after repair or reconstruction with early ligament function dependent on cellular population of the repair but early graft function dependent on the maintenance of organized collagen.

Following various types of naturally-occurring traumatic injury to an articular joint, the lubricating ability of synovial fluid is impaired, with a correlated alteration in the concentration and/or structure of lubricant molecules, hyaluronan and proteoglycan-4. However, the effect of arthroscopic cartilage repair surgery on synovial fluid lubricant function and composition is unknown. Arthroscopic treatment of full-thickness chondral defects in horses with (1) platelet-enriched fibrin or (2) platelet-enriched fibrin+mesenchymal stem cells leads to equine synovial fluid with impaired lubricant function and hyaluronan and proteoglycan-4 composition. Controlled Laboratory Study. Equine synovial fluid was aspirated from normal joints at a pre-injury state (0 days) and at 10 days and 3 months following fibrin or fibrin+mesenchymal stem cell repair of full thickness chondral defects. Equine synovial fluid samples were analyzed for friction-lowering boundary lubrication of normal articular cartilage (static and kinetic friction coefficients) and concentrations of hyaluronan and proteoglycan-4, as well as molecular weight distribution of hyaluronan. Experimental groups deficient in lubrication function were also tested for the ability of exogenous high-molecular weight hyaluronan to restore lubrication function. Lubrication and biochemical data varied with time after surgery but generally not between repair groups. Relative to pre-injury, kinetic friction was higher (+94%) at 10 days but returned to baseline levels at 3 months while static friction was not altered. Correspondingly, hyaluronan concentration was transiently lower (-64%) and shifted towards lower molecular weight forms, while proteoglycan-4 concentration was increased (+210%) in 10-day samples relative to pre-injury levels. Regression analysis revealed that kinetic friction decreased with increasing total and high molecular weight hyaluronan. Addition of high molecular weight hyaluronan to bring 10-day hyaluronan levels to 2.0mg/ml restored kinetic friction to pre-injury levels. Following arthroscopic surgery for cartilage defect repair, synovial fluid lubrication function is transiently impaired, in association with decreased hyaluronan concentration. This functional deficiency in synovial fluid lubrication can be counteracted in vitro by addition of high molecular weight hyaluronan. Synovial fluid lubrication is deficient shortly following arthroscopic cartilage repair surgery, and supplementation with high molecular weight hyaluronan may be beneficial.

Background: There has been recent interest in the effect of nonsteroidal anti-inflammatory medications on musculoskeletal healing. No studies have yet addressed the effect of these medications on meniscal healing. Hypothesis: The administration of ketorolac in the perioperative period will result in higher rates of meniscal repair clinical failure. Study design: Cohort study; Level of evidence, 3. Methods: A total of 110 consecutive patients underwent meniscal repair at our institution between August 1998 and July 2001. Three patients were lost to follow-up, and the remaining 107 (mean age, 15.9 ± 4.4 years) had a minimum 5-year follow-up (mean follow-up, 5.5 years). Thirty-two patients (30%) received ketorolac perioperatively. The primary outcome measure was reoperation for continued symptoms of meniscal pathology. Asymptomatic patients were evaluated by the International Knee Documentation Committee (IKDC) Subjective Knee Form, Short Form-36 (SF-36) Health Survey, and Knee Outcome Osteoarthritis Score (KOOS). Results: Kaplan-Meier survivorship revealed no difference in reoperation rates with and without the administration of perioperative ketorolac (P = .95). There was an overall failure rate of 35% (37/107 patients), with a 34% failure rate in patients receiving ketorolac (11/32 patients). Multivariable Cox regression confirmed that age, duration of symptoms, meniscal tear type, fixation technique, concurrent anterior cruciate ligament repair, and ketorolac usage did not have an impact on the rate of failure (P > .05 for all; ketorolac use, P > .50). Female sex (P = .04) and medial location (P = .01) were predictive of an increased risk for reoperation. Conclusion: Failure of meniscal repair was not altered with the administration of perioperative ketorolac. Further work studying the effects of longer term anti-inflammatory use after meniscal repair is necessary before stating that this class of medications has no effect on meniscal healing. Clinical relevance: Results of this study suggest that nonsteroidal anti-inflammatory ketorolac can be administered perioperatively during a meniscal repair procedure to harness its benefits of decreased narcotic requirement, decreased pain, and shorter length of hospital stay without negatively influencing the long-term outcome of the surgery.

Background: Muscle strains are one of the most common injuries treated by physicians. Standard conservative therapy for acute muscle strains usually involves short-term rest, ice, and non-steroidal anti-inflammatory medications, but there is no clear consensus regarding treatments to accelerate recovery. Recently, clinical use of platelet-rich plasma (PRP) has gained momentum as an option for therapy and is appealing for many reasons, most notably because it provides growth factors in physiological proportions and it is autologous, safe, easily accessible, and potentially beneficial. Local delivery of patients' PRP to injured muscles can hasten recovery of function. However, specific targeting of PRP to sites of tissue damage in vivo is a major challenge that can limit its efficacy. Hypothesis: Location of PRP delivery can be monitored and controlled in vivo with non-invasive tools. Study design: Controlled laboratory study using rats. Methods: Superparamagnetic iron oxide nanoparticles (SPIONs) can be visualized by both MRI (in vivo) and fluorescence microscopy (after tissue harvesting). We labeled PRP with SPIONs and administered intramuscular injections of SPION-containing platelets. MRI was used to monitor the ability to manipulate and retain the location of PRP in vivo by placement of an external magnet. Platelets were isolated from whole blood and incubated with SPIONs. Following SPION incubation with PRP, a magnetic field was used to manipulate platelet location in culture dishes. In vivo, the tibialis anterior muscles (TAs) of anesthetized Sprague-Dawley rats were injected with SPION-containing platelets and MRI was used to track platelet position with and without a magnet worn over the TAs for 4 days. Results: The method used to isolate PRP yielded a high concentration (almost 4-fold increase) of platelets. In vitro experiments show that the platelets successfully took up SPIONs and then rapidly responded to an applied magnetic field. Platelets without SPIONs did not respond to the magnetic field. In vivo experiments show that the SPION-containing platelets can be non-invasively maintained at a specific site with the application of a magnetic field. Conclusion: PRP may be a useful product in clinical treatment of muscle injuries, but one problem with using PRP as a therapeutic tool, is retaining PRP at the site of injury. We propose a potential solution with our findings that support this method at the cell, whole muscle, and in vivo levels. Controlling the location of PRP will allow the clustering of PRP to enrich the target area with growth factors and will prevent loss of the platelets over time at the site of injury.

Objectives: Single-point and double-point arthroscopic reconstruction techniques for acute osseous Bankart lesions have been described in the literature. We hypothesized that the double-point fixation technique (bony Bankart bridge) would provide superior fracture reduction and stability at time zero compared to the single-point technique in a cadaveric bony Bankart model. Methods: Testing was performed on 14 matched glenoid pairs with simulated bony Bankart fractures; the defect width was 25% of the glenoid diameter and the fracture was perpendicular to the 3 o’clock position. Additionally, a labral avulsion was created and extended from the 6 to the 12 o’clock position. All labral avulsions were then repaired above and below the bony Bankart with suture anchors. Half of the bony Bankart fractures were repaired with a double-point technique, while the contralateral glenoid was repaired with a single-point technique (Fig 1). Following the repairs, distance between the intra-articular surfaces of the fragment and glenoid were measured for an unloaded condition and with 10 N of tension applied to the fragment, to quantify fracture displacement. To determine the biomechanical stability of the repairs, specimens were secured in a tensile testing machine and aligned so that the load vector was 30° medial to the superior-inferior plane. The repair constructs were preconditioned with sinusoidal cyclic loading between 5 N to 25 N for 10 cycles and then pulled to failure at a rate of 5 mm/min. Load (N) at 1 mm and 2 mm of fracture displacement were determined. Non-parametric statistics were used (MWU). Results: The bony Bankart defect length measured more than half of the maximum antero-posterior diameter of the inferior glenoid in all specimens. Loads at 1 mm and 2 mm of fracture displacement, and fracture reduction are reported in Table 1. The double-point technique required significantly higher forces to achieve fracture displacements of 1 mm (mean: 60.6 N, range: 39.0 N to 93.3 N; p = 0.001) and 2 mm (mean: 94.4 N, range: 43.4 N to 151.2 N; p = 0.004) (Fig 1) than the single-point technique (1 mm displacement mean: 30.2 N, range: 14.0 N to 54.1 N; 2 mm displacement mean: 63.7, range: 26.6 to 118.8). Fracture displacement was significant lower after double-point repair for both the unloaded condition (mean: 1.1 mm, range: 0.3 to 2.4 mm; p = 0.005) (Fig 1) and in response to a 10 N anterior force applied to the defect (mean: 1.6 mm, range: 0.5 to 2.7 mm; p = 0.001) compared to single-point repair (unloaded mean: 2.1 mm, range: 1.3 to 3.4 mm; loaded mean: 3.4, range: 1.9 to 4.7 mm). Conclusion: The double-point fixation technique (bony Bankart bridge) for clinically relevant sized, acute osseous Bankart lesions resulted in lower fracture displacement and superior stability at time zero in comparison to the single-point technique and was the preferred biomechanical technique in this model of bony Bankart fractures. This information may influence the surgical technique used to treat large osseous Bankart fractures and the postoperative rehabilitation protocols implemented when such repair techniques are used.

Objectives: After failure of conservative treatment, surgical repair has long been the primary treatment option for unstable superior labrum anterior and posterior (SLAP) lesions of the shoulder. There is growing evidence supporting both biceps tenotomy and tenodesis as effective alternative treatments for SLAP lesions. The surgical trends among recent graduates, however, have not been evaluated. The goal of this study was to determine the rates of SLAP repair, biceps tenodesis, and biceps tenotomy for patients with isolated SLAP tears. As a secondary goal, we aimed to determine the rates of SLAP repair, biceps tenodesis, and biceps tenotomy for patients with SLAP tears undergoing concomitant rotator cuff repair. Methods: A query of the American board of orthopaedic surgery (ABOS) certification examination database was performed from 2002-2011. The database was searched for patients with isolated SLAP lesions undergoing SLAP repair, biceps tenodesis, or biceps tenotomy. The database was then queried a second time for patients with SLAP lesions undergoing concomitant arthroscopic rotator cuff repair, to determine the rates of SLAP repair, biceps tenodesis, or biceps tenotomy. Results: From 2002-2011 there were 8,963 cases reported for treatment of an isolated SLAP lesion, and 1540 cases reported for the treatment of SLAP lesion with concomitant rotator cuff repair. Over the study period, for patients with isolated SLAP lesions the proportion of SLAP repairs decreased from 69.3% to 44.8% (p<0.0001), while the proportion of biceps tenodesis increased from 0.2% to 9.3% (p<0.0001) and the proportion of biceps tenotomy increased from 0.4% to 1.7% (p=0.018). For patients undergoing concomitant rotator cuff repair, similar trends were observed as the proportion of SLAP repairs decreased from 60.2% to 15.3% (p<0.0001), while the proportion of those undergoing biceps tenodesis or tenotomy increased from 1.2% to 20.3% (p<0.0001). There was also a significant difference in the mean age of patients undergoing SLAP repair (37.1 years of age) vs biceps tenodesis (48.7 years of age) vs biceps tenotomy (55.7 years of age) (p <0.0001). Surgeons with a declared subspecialty in Shoulder and Elbow surgery performed biceps tenodesis for 17% of isolated SLAP tears, whereas candidates with a declared subspecialty in Hand and Upper Extremity, Sports Medicine, and General Orthopaedics utilized biceps tenodesis in 2-3% of cases involving isolated SLAP tears (p<0.05). Conclusion: Practice trends for orthopaedic board candidates indicate the proportion of SLAP repairs has decreased over time with an expected increase in biceps tenodesis and tenotomy. Increased patient age correlates with likelihood of treatment with biceps tenodesis or tenotomy versus SLAP repair. Candidate surgeons with subspecialty training in Shoulder and Elbow surgery perform more biceps tenodesis for isolated SLAP tears as compared to other subspecialty trained surgeons.

Objectives: While anterior glenohumeral instability has been shown to be common in young athletes, the risk factors for injury are poorly understood. The elucidation of risk factors is critical to help develop prevention strategies. We hypothesized that specific modifiable and non-modifiable factors at baseline would be associated with the subsequent risk of injury in a cohort of young athletes. Methods: We conducted a prospective cohort study in which 714 young athletes were followed from June 2006 through May 2010. Baseline assessments included a subjective history of instability, physical examination by a sports-trained orthopaedic surgeon, range-of-motion, strength with a hand-held dynamometer, and bilateral noncontrast shoulder MRI. A musculoskeletal radiologist measured glenoid version, glenoid height, glenoid width, glenoid index (height-to-width ratio), glenoid depth, rotator interval (RI) height, RI width, RI area, RI index, and the coracohumeral interval. Subjects were followed to document all acute anterior shoulder instability events during the 4 year follow-up period. The time to shoulder instability event during the follow-up period was the primary outcome of interest. Univariate and multivariable Cox proportional hazards regression models were used to analyze the data. Results: We obtained complete data on 714 subjects. During our 4 year surveillance period, there were 38 anterior instability events documented. While controlling for covariates, significant risk factors of physical exam were: apprehension sign HR=2.96 (1.48, 5.90, p=0.002) and relocation sign HR=4.83 (1.75, 13.33, p=0.002). Baseline range-of-motion and strength measures were not associated with subsequent injury. Significant anatomic risk factors on MRI measurement were glenoid index HR=8.12 (1.07, 61.72) p=0.043 and the coracohumeral interval HR=1.20 (1.08, 1.34, p=0.001). Conclusion: This prospective cohort study revealed significant risk factors for shoulder instability in this high-risk population. While modifiable risk factors such as strength and range-of-motion were not associated with subsequent instability, some non-modifiable risk factors were. That the exam findings of apprehension and relocation were significant while controlling for prior history of injury suggests that patients may be unaware of prior instability episodes. The anatomic variables of significance are also not surprising - tall and thin glenoids were at higher risk compared to short and wide glenoids; and the risk of instability increased by 20% for every 1mm increase in coracohumeral distance.

Purpose With increased sports participation and medical community awareness, there appears to be an increase in pediatric musculoskeletal injuries. Our purpose was to identify the intra-articular injury pattern seen within the pediatric shoulder. Methods A retrospective review was performed at two tertiary-care children’s hospitals between 2008 and 2011 on all patients who underwent magnetic resonance imaging (MRI) and subsequent shoulder arthroscopy. Exclusion criteria included: girls >14 years old and boys >16 years old. Demographics, MRI and arthroscopic findings were recorded. Labral pathology was grouped: Zone I (Bankart lesions, 3–6 o’clock for right shoulder), Zone II (posterior labral lesions, 6–11 o’clock), Zone III (SLAP lesions, 11–1 o’clock), and Zone IV (anatomic variants, 1–3 o’clock). Results One hundred and fifteen children met criteria, mean age 14.4 years (range 8–16). There were 24 girls and 91 boys, with 70 right shoulders. Of 108 children, labral pathology involved: 72 Zone I (16 isolated anterior), 56 Zone II (15 isolated posterior), 38 Zone III (four isolated superior), and three had an isolated Buford complex. Seventy had more than one labral zone injured, and 31 (30 %) had more than two zones injured. Non-labral pathology included partial rotator cuff tears and humeral avulsions of the glenohumeral ligament. Conclusion With 94 % of intra-articular pathology being labral tears, the distribution of proportion in children differs from adults; moreover, 23 % involved only the posterior or posterosuperior labrum. Treating surgeons should be prepared to find anterior tears extending beyond the zone of a classic Bankart lesion and an association with C rotator cuff tears.

Objectives: The interval throwing progression is a hallmark of the rehabilitation program designed for baseball pitchers or position players returning from shoulder or elbow injury. It typically begins with flat-ground throws at a short distance and progressively increases to 180 feet or more. For pitchers, this phase is then followed by throwing off the mound, progressing from partial-effort to full-effort pitches. Theoretically, the progression of throwing phases allows an injured athlete to gradually recover his flexibility, arm strength, and mechanics while moving from less stressful activities to more stressful activities. While this throwing program has been a part of baseball rehabilitation and conditioning for decades, little is known about the biomechanical stresses generated during flat-ground throwing or variable effort pitching off the mound. Methods: Twenty-nine healthy, college baseball pitchers were analyzed using a quantitative motion analysis system. The participants threw from flat ground at distances of 60-ft, 90-ft, 120-ft, and 180-ft, being instructed to throw “hard, on a horizontal line”. The pitchers then threw fastballs from a mound at 3 different efforts: 60% effort, 80% effort, and full-effort. Biomechanical parameters of position, velocity, and kinetic values were recorded. Mean values were calculated for humeral internal rotation torque (HIRT) and elbow valgus load (EVL) for each throw type. This data was then used to compare shoulder and elbow stresses between the various throws. The differences among mean values were analyzed with a repeated-measures analysis of variance (ANOVA). Post hoc paired t tests were performed when the ANOVA revealed a significant difference. Results: Statistically significant differences exist across all mound intensities (60%, 80%, and 100% effort) for nHIRT (p=0.03) and nEVL (p=0.04), as both parameters increased with percentage throwing effort. No statistically significant differences were found across all flat ground distances in either nHIRT or nEVL (p>0.05). No statistically significant difference in peak HIRT or peak EVL were found when comparing full effort pitching to flat ground throws at any distance (p>0.10). The longer flat ground throws at 180 feet did show significantly different kinematics and biomechanical patterns when compared with pitching from the mound, while shorter flat ground throws had patterns similar to those of pitching. Conclusion: Variable effort pitching off the mound demonstrates significantly lower stresses on the shoulder and elbow during partial-effort throws, illustrating the importance of these throws during the recovery and rehabilitation process. Flat ground throwing at distances as short as 60 feet had similar biomechanical stresses on the upper extremity when compared with pitching full-effort from the mound. Despite lower velocity, this similar stress illustrates the mechanical disadvantage of throwing from the flat ground in a stationary position. No increase in shoulder or elbow stress was seen with increasing distances from the flat ground, likely because the pitchers began using a “crow-hop” for the longer distances, facilitating the throw with their lower extremity. The mechanical advantage of throwing from a mound or using the crow-hop may be protective during rehabilitation and training throws, generating lower humeral internal rotational torque, lower elbow valgus load, and more throwing efficiency.

Objectives: In the setting of injury, meniscal repair and preservation is the goal when possible. Current research on second generation all-inside repair systems is limited to a maximum of three year follow-up. The purpose of this study is to evaluate the long-term (> 5 years) clinical success of isolated meniscal repairs and those performed with concomitant ACL reconstruction using a second generation all-inside repair device. Methods: This a retrospective review of patients who underwent meniscal repair utilizing the all-inside FasT-Fix meniscal repair system (Smith & Nephew Arthroscopy, Andover, MA) between December 1999 and January 2007. Eighty-three meniscal repairs in 81 patients were identified and follow-up was obtained in 90%. Twenty-six patients (35%) had isolated meniscal repair. Clinical failure was defined as repeat surgical intervention involving resection or revision repair. Clinical outcomes (KOOS, IKDC, Marx Activity) were also assessed. Results: Minimum follow-up was 5 years (avg. 7 years). Twelve patients failed meniscal repair (16%). The average time to failure was 47 months (range, 15 - 94). There was no difference in average patient age, sex or number of sutures utilized between successful repairs and failures. There was no difference in failure rate between isolated repairs (11.5% CI: -0.76%-23.76%) and those performed with concurrent ACL reconstruction (18.3% CI: 7.47%-29.13%) and the average time to failure was similar between these two groups (48.1 months versus 46.6 months, p=0.243). Postoperative outcome scores were also similar (KOOS and IKDC). Conclusion: This first report of long term (> 5 yrs) follow-up of second generation all-inside meniscal repair demonstrates it is an effective method of primary meniscal repair for both isolated repairs and those performed with concurrent ACL reconstruction. After minimum five year follow-up, over 84% of patients continue to demonstrate successful repair. Treatment success is further supported by favorable results on patient based outcome measures.

Objectives Patients with anterior cruciate ligament (ACL) injury are at high risk for the development of post-traumatic osteoarthritis (PTOA), despite ACL reconstruction (ACLR). ACL injuries are frequently associated with damage of other structures within the knee, such as the meniscus. The meniscus is an important structure that provides protection for articular cartilage and stabilization of the joint. Long-term studies of PTOA after ACLR mainly used radiographs. Conventional magnetic resonance imaging (MRI) has been used in a limited number of studies to evaluate structural damages, but this only provides information on morphologic changes that occur at relatively late stages of the disease. In this study, we aim to use quantitative MRI (qMRI) to evaluate cartilage and meniscus degeneration in patients at 10 years after ACLR. Methods This is a multi-site multi-vendor study that involves three sites and two MR platforms (Siemens 3T and Philips 3T). MRI protocols have been harmonized between sites and cross validation data were collected using phantoms. The patients are from a nested cohort within Multicenter Orthopaedic Outcomes Network (MOON) Onsite Cohort at 10 years after ACLR. Inclusion/Exclusion criteria were: 22-50 years old; ACL tear during a sport; no previous knee injury; no graft rupture during follow-up. In this preliminary report, 51 patients (age 32.8 ± 6.4 years; 25 females; body mass index [BMI] 25.7 ± 5.7 kg/m2; 40 hamstring autograft, 9 bone-patellar tendon-bone autograft, and 2 allograft) and 17 healthy control participants (age 30.8 ± 7.8 years; 10 females; BMI 23.8 ± 5.6 kg/m ² ) were studied. The MRI protocol included high-resolution Dual-Echo Steady State (DESS), and combined gradient echo MAPSS T1ρ and T2 mapping. Cartilage and meniscus were automatically segmented on DESS images using an in-house developed deep-learning model into medial/lateral femoral condyle (MFC/LFC), medial/lateral tibia (MT/LT), trochlear (TRO), and patellar cartilage (PAT), and medial and lateral menisci (MM/LM). Each cartilage compartment was further divided into sub-regions based on a modified MRI Osteoarthritis Knee Score (MOAKS) definition: central and posterior for MFC/LMC (cMFC/cLMC, pMFC/pLMC); anterior, central, and posterior for MT/LT (aMT/aLT, cMT/cLT, pMT/pLT); medial, central, and lateral for PAT/TRO (mPAT/mTRO, cPAT/cTRO, lPAT/lTRO). Menisci were further divided into anterior horn (aMM, aLM), central (body) (cMM, cLM), and posterior horn (pMM, pLM) subregions. These cartilage and menisci subregions were then transformed and overlaid onto the T1ρ and T2 parameter maps after co-registering the DESS image to the first echo of the 3D MAPSS sequence using the Elastix toolbox. T1ρ and T2 parameter maps were obtained by a voxel-wise two-parameter monoexponential fitting. The mean and standard deviation for each subregion was recorded and compared between three knee groups: operated and contralateral knees from patients, and control knees from healthy controls, using a mixed-effects regression model, adjusted for age, sex, and BMI. Results For cartilage, compared to contralateral knees, operated knees in patients had significantly higher T1ρ and T2 values in MFC, MT, and TRO compartments. Looking into subcompartments, for MFC, MT, and TRO, most of the subcompartments (cMFC, pMFC; cMT, pMT; mTRO, cTRO) showed significantly higher T1ρ and T2 values compared to contralateral knees. For LFC and LT, only the posterior subcompartments showed significantly higher T1ρ and T2 values compared to contralateral knees. For PAT, no significant differences were observed between operated and contralateral knees. Compared to healthy control knees, operated knees in patients had significantly higher T1ρ and T2 values in all the six compartments. Besides, contralateral knees also showed higher T1ρ and T2 values in LFC, LT and PAT compartments compared to healthy control knees (Figure 1 for T1ρ, T2 with similar trend was not shown). For meniscus, no significant differences in T1ρ and T2 values were observed between injured and contralateral knees. Compared to healthy control knees, both operated and contralateral knees in patients had significantly higher T1ρ values in LM and significantly higher T2 values in MM (Figure 2). Conclusions Cartilage T1ρ and T2 values were higher in operated knees compared to contralateral knees at 10 years after ACLR, except for patellar compartment. In patellar cartilage, no significant differences were observed between sides in patients, but both sides were significantly higher than control knees. Our data showed that contralateral knees after ACLR may not represent ‘healthy controls’ as there might be compensatory changes and early degeneration in contralateral knees as a result of injury and surgery to their other knee. Although we observed this general trend of higher cartilage T1ρ and T2 values in the operated knees compared to contralateral knees, no significant differences were observed in meniscus T1ρ and T2 values between sides in patients, suggesting the timing of cartilage and meniscus degeneration may be different for patients after ACLR. Meniscus T1ρ and T2 values in both sides are higher than control knees, suggesting early degeneration in meniscus in patients in both sides. The results will be confirmed with more patient data being collected in the ongoing study. The relationship between qMRI, morphological tissue changes, and patient-reported outcomes after ACLR will also be evaluated in future work. [Figure: see text][Figure: see text]

Objectives Basic science evidence suggests that quadriceps tendon (QT) autograft is a viable alternative to bone-patellar-tendon-bone (PT) autograft for anterior cruciate ligament (ACL) reconstruction due to promising anatomic, histologic, and biomechanical factors. Little evidence exists, however, comparing short and long-term functional outcomes between these two graft sources in a primary setting. The purpose of this study was to compare graft re-injury rates, return to cutting/pivoting sports rates, complications, and self-reported knee function at two years in individuals receiving primary ACL reconstruction with QT versus PT autograft. Methods A matched case-control study was conducted in accordance with the Strengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines using a single-surgeon ACL database of 1,324 patients to identify 108 (54 PT and 54 QT) patients undergoing primary ACL reconstruction between 2015-2018 (Figure 1). Patients were age and gender matched and between groups comparisons were examined at the time of return to sport and 24 months postoperatively. Data gathered at return to sport included knee range of motion (ROM), single leg squat and single leg hop symmetry, self-reported knee function (IKDC-2000, International Knee Disability Committee), and psychological readiness (ACL-RSI, ACL-Sport After Injury (ACL-RSI). Injury surveillance was conducted for 2-years to determine graft re-injury rates, and at 24-monts level of sports participation, the prevalence of anterior knee pain (Kujala Scale), and self-reported knee function via the Single Assessment Numeric Evaluation (SANE) scores were obtained. Univariate models were utilized to compare groups differences and an alpha of .05 was used to determine statistical significance using SPSS (version 25, IBM Inc., New York, USA). Results No baseline patient or surgical demographic differences were observed between groups (Table 1). Patients receiving QT autograft had higher single leg squat symmetry (98.2 ±2.8% v 96.1 ±3.0%, P = .001) at time of return to sport. No significant differences existed at time of return to sport (Table 2) regarding knee ROM, single-leg hop test symmetry, self-reported knee function, psychological readiness, or time to return to sport (8.4 +2.5 mo vs 8.1 ±3.5 mo; P = .486). At two years, there were no significant differences in re-injury rates (0.0% vs 1.2%, P=.383), the prevalence of anterior knee pain, or SANE scores (Table 3). The PT group were significantly more likely to be participating in level I/II (cutting) sports (84.9% vs 69.2%, P=.001) at two years. Conclusions Patients receiving QT autografts demonstrated comparable self-reported and functional outcomes at time of return to sport and two-year follow-up to those receiving PT autografts. Surgeons should consider utilizing similar rehabilitation timelines and functional performance goals for patients following ACL reconstruction with QT and PT graft options.

Objectives Recurrent anterior shoulder instability after arthroscopic Bankart repair presents a challenging clinical problem, with the primary stabilization procedure often portending the best chance for clinical success. While the glenoid track concept continues to evolve, a limitation of the glenoid track is that it relies on bony anatomy without specific considerations for capsuloligamentous integrity or the effect that capsular laxity may have on the glenohumeral contact points throughout shoulder range of motion. The purpose of the study was to determine if capsuloligamentous laxity has a modifying effect on the glenoid track, specifically for on-track lesions with a small distance to dislocation (DTD) from being an off-track lesion or the so-called “near-track” lesion. This may explain why some on-track lesions are at an increased risk of recurrent instability. We hypothesized that patients with ligamentous laxity and “near track” lesions would be at increased risk of recurrent instability following arthroscopic Bankart repair. Methods Consecutive patients with on-track Hill-Sachs lesions who underwent primary arthroscopic Bankart repair alone without remplissage for recurrent anterior glenohumeral instability between January 2007 and December 2015 at a single institution were retrospectively reviewed. Patients with less than 2-year follow up, glenoid bone loss > 20%, off-track lesions, concomitant remplissage, and atraumatic instability were excluded. Determination of shoulder laxity was based on exam under anesthesia (EUA), including anterior load and shift, posterior load and shift, and sulcus testing at the time of surgery before arthroscopy. Capsuloligamentous shoulder hyperlaxity was defined as external rotation of >85 o and/or grade of 2+ or greater load and shift in two or more planes. Measurements of glenoid bone loss, Hill-Sachs interval (HSI), and glenoid track (GT) were performed based on prior described methods. DTD was calculated (DTD=GT-HSI, with DTD>0 classified as on-track lesions). Near track lesions were defined as 0<DTD<8mm. Failure was defined as recurrent dislocation. Results A total of 173 patients were initially identified, of which 151 met inclusion criteria and were included for analysis. 72.8% of patients were males and mean age was 20.1 ± 5.7 years. Patients were divided into two groups based on shoulder laxity; group 1 consisted of 74 patients with hyperlaxity, and group 2 consisted of 77 patients without hyperlaxity. Overall, 21 patients (13.9%) sustained a recurrent dislocation and 35 patients (23.2%) had recurrent instability episodes. Failure was associated with glenoid bone loss (p<0.001 ), longer HS length ( p=0.007), occurrence of >1 instability episode preoperatively (p=0.018 ), and smaller DTD ( p=0.0008). Hyperlaxity was associated with the use of more anchors ( p=0.0001). Shoulder laxity was not independently predictive of overall failure (Figure 1, p=0.18); however, DTD was significantly associated with failure risk and recurrent instability in patients with hyperlaxity ( p=0.006) specifically in younger patients with hyperlaxity (Figure 1, Table 1). Conclusions Our study suggests that while capsuloligamentous laxity is not independently predictive of failure after arthroscopic Bankart repair for on-track lesions, laxity may play a significant role in clinical outcomes in patients with a small DTD or near-track lesions. In younger patients with near-track lesions, hyperlaxity may be particularly predictive of failure after arthroscopic Bankart repair. As our understanding of the glenoid track continues to evolve, surgeons may need to consider the track concept as a continuum with evolving surgical algorithms other than an arthroscopic Bankart alone in young patients with near track lesions and hyperlaxity. [Table: see text]

Objectives Recurrent traumatic anterior shoulder instability occurs most commonly in young to middle-aged male athletes. The Latarjet procedure was reported to enable early return to sport compared to capsulolabral repair. Recent research has highlighted the negative effect of immobilization on shoulder rehabilitation. However, only few studies evaluated different rehabilitation programs after open Latarjet and their potential impact on complication rates, stiffness and time to return to sport. The reported immobilization periods ranged from zero to three weeks, and different types of mobilization protocols were used. The aim of this study was to evaluate the benefit of sling immobilization after open Latarjet procedure for anterior shoulder instability. The hypothesis was that immediate self-rehabilitation without sling immobilization would result in improved functional scores at 6 months compared to patient wearing a sling for 3 weeks postoperatively. Methods We randomized 72 patients with anterior shoulder instability scheduled for open Latarjet procedure into sling and no-sling groups. Two partially 1 cm apart threaded 4.0-mm cancellous screws were used to secure the graft. Both groups started the same immediate self-rehabilitation protocol. Patients were evaluated clinically using Rowe score, the Single Assessment Numeric Evaluation (SANE) instability score as well as visual analogue pain scale (VAS) preoperatively and at 1.5, 3, and 6 months. A computed tomography was performed at 6 months to evaluate graft healing. Results Both groups had similar preoperative patient characteristics. Both groups had a significant improvement in Rowe score (from 38.8 ± 20.4 to 81.6 ± 17.8, p < 0.001), SANE instability score (from 42.5 ± 20.5 to 84.7 ± 13.2, p < 0.001) and VAS (from 27.7 ± 21.8 to 13.9 ± 16.1, p < 0.001) at 6 months postoperative. There was no difference in functional outcomes between the two groups at 6 months. Mean Rowe score was respectively 80.7 ± 15.9 and 82.6 ± 19.6 in the sling and no-sling group (p = 0.64). Mean SANE instability score was 83.7 ± 13.0 and 85.7 ± 13.6 (p = 0.53) and mean VAS 15.6 ± 14.8 versus 12.2 ± 17.5 (p = 0.38), for sling and no-sling group respectively. Finally, computed tomography evaluation revealed no significant differences regarding bone graft healing between both groups (p = 0.35). Conclusions Both treatment groups resulted in excellent early functional outcomes. Absence of sling immobilization did not increase complication rates after open Latarjet. Sling immobilization seems therefore optional after open Latarjet procedure.

Objectives This study aimed to evaluate the safety and efficacy of performing a lateral extra-articular tenodesis (LET) with a modified Lemaire technique (MLT) in conjunction with anterior cruciate ligament reconstruction (ACLR) in children and adolescents at increased risk for failed ACLR. Methods A consecutive series of patients ≤19 years who underwent simultaneous ACLR and LET with minimum two-year follow-up data were reviewed. Patients were indicated for LET when one or more of the following risk factors were present: participant in high-risk competitive sport such as football, lacrosse, soccer or basketball, grade 3 pivot shift, hyperlaxity (Beighton score > 6), recurvatum, revision ACLR, contralateral ACLR, or chronic ACL insufficiency. ACLR was performed using either full-thickness quadriceps tendon (QUAD) for skeletally immature patients or bone-patellar tendon-bone (BTB) autograft for skeletally mature patients. All-epiphyseal (AE) or complete transphyseal (CT)techniques were used depending on patients’ skeletal maturity. At a minimum two-year follow-up, patient-reported outcome measures included Single Assessment Numeric Evaluation (SANE), Pediatric International Knee Documentation Committee (Pedi-IKDC), and the HSS Functional Activity Brief Scale (HSS Pedi-FABS) scores. Return-to-sport (RTS)data and second surgeries were also obtained. Results Sixty-one consecutive patients (mean age 15.17 ±1.73 years, range 11-19 years, 62% female) were analyzed (Table 1). 59 patients (97%) participated in organized sports including soccer, basketball, football and lacrosse, with soccer being the most popular one. The average grade at the time of surgery was 9 th grade. Ten patients (16%) were revision ACLR procedures. Seven (11%) patients underwent AE and 54 (89%) underwent CT ACLR. Forty-two (69%) cases employed a QUAD autograft, while 19 (31%) utilized a BTB autograft. All patients underwent a LET with a MLT and 2 patients underwent simultaneous implant mediated guided growth with a plate for structural genu valgum. At two-year follow-up, mean SANE score was 95, median Pedi-IKDC score was 91, and median HSS-Pedi Fabs score was 27. RTS rate was 91.8%. Ten patients had subsequent surgical procedures, including two hardware removal procedures for hemiepiphysiodesis, three contralateral ACLR, three meniscus surgeries, one lysis of adhesions, and one revision ACLR for BTB graft re-rupture. Two patients were lost to follow-up and excluded from the study. Conclusions The findings suggest that concomitant LET and ACLR in adolescent patients with risk factors for failed ACLR is associated with favorable patient-reported outcomes, high return to sports participation, and low ACL re-rupture rate at two years follow-up. [Table: see text]

Objectives ACL reconstruction is one of the most common knee procedures performed annually in the United States. Athletes participating in cutting and pivoting sports are at high risk for ACL injury. In the general population, most graft choices including allograft, bone-patellar tendon-bone (BTB) autograft, hamstring autograft and quadriceps autograft have all been shown to excellent results following reconstruction. However, in the high-level cutting and pivoting athlete, the optimal graft for reconstruction remains controversial. Most consider BTB autograft to be the gold standard for such athletes. However, BTB autografts have drawbacks including anterior knee pain, difficulty kneeling and possible patellar fracture and patellar tendon rupture. Quadriceps autograft has increased in popularity since it offers a thicker graft with more favorable tensile properties compared to BTB and hamstring autografts. The quadriceps autograft has nearly twice the cross sectional area, higher load to failure and greater stiffness than the BTB autograft. Studies have shown equivalent outcomes when directly comparing BTB autograft vs. soft tissue quadriceps autograft in the general population. No studies have directly compared these two grafts in athletes participating in cutting and pivoting sports. We hypothesized that the quadriceps autograft would lead to similar patient outcomes, re-tear rates, return to sport and complications as BTB autografts in the cutting and pivoting athlete. Methods A retrospective review of cutting and pivoting athletes with ACL tears treated with BTB autograft or soft tissue quadriceps autograft with at least 2 years of follow up was performed. Only athletes participating in cutting and pivoting sports were included in the study. Four sports were considered to be cutting and pivoting including soccer, football, lacrosse and basketball. The decision on which graft to use was based on the athlete’s choice after discussing the pros and cons of each graft. Exclusion criteria included those athletes with recurrent ACL tears, multiligamentous injuries, previous meniscal surgery and those requiring osteotomies. International Knee Documentation Committee Subjective Knee Evaluation (IKDC) and Lysholm knee scoring scale were used to evaluate patient reported outcomes. Through chart review, ability to return to sport, time to return to sport and complications were identified. The postoperative rehabilitation protocol for both grafts was identical. Results There were 32 athletes in the soft tissue quadriceps autograft group and 36 in the BTB autograft group. The average age was 18.6 years for the quad group and 19.7 years for the BTB autograft group (p=0.63). Females made up 62.5% of the quadriceps group and 44.4% of the BTB group (p=0.14). The quad group was made up of 56.3% high school and 43.7% college athletes compared to 61.1% high school and 38.9% college athletes in the BTB autograft group (p=0.53). Soccer was the most common sport with 16 in the quad group and 14 in the BTB group. The rest of the quad group included 8 football players, 4 lacrosse and 4 basketball players. The remaining BTB group consisted of 12 football players, 8 lacrosse and 2 basketball players. Meniscal surgery was performed in combination with the ACL reconstruction in 17 (53.1%) of the quad group and 22 (61.1%) of the BTB autograft group (p=0.37). Average graft size was 9.5mm for the quad autograft group and 10 for the BTB autograft group. The 2-year IKDC score was 93.6 for the quad group and 95.1 for the BTB group (p=0.45). The 2 year Lysholm scores were 95.7 and 96.1 for the quad and BTB groups respectively. Return to play at the same or higher level was 90.6% in the quad group and 86.1% in the BTB autograft group (p=0.82). Time to return was also similar between the groups with 7.1 months for the quad group and 7.6 months for the BTB autograft group. There was 1 re-tear which required revision in the BTB group and no re-tears in the quad group (p=0.34). Arthrofibrosis requiring MUA and lysis of adhesions occurred in 2 quad autografts and 4 BTB autografts (p=0.49). One contralateral ACL rupture occurred in the quad autograft group and 4 in the BTB autograft group (p=0.21). Conclusions The optimal ACL graft in high level athletes participating in cutting and pivoting sports remains in question. In our comparison of quadriceps autograft compared to BTB autograft in this athletic population, no difference in patient reported outcomes, return to sport or re-tear rates was identified. Based on these findings, quadriceps autograft is as effective as BTB autografts in cutting and pivoting athletes and should be part of the graft choice discussion with the athlete.

Objectives To evaluate the efficacy of a multimodal non-opioid analgesic protocol in controlling postoperative pain compared to opioids following a primary arthroscopic rotator cuff repair. Methods Seventy consecutive patients undergoing a primary rotator cuff repair were assessed eligibility. A prospective randomized controlled trial was designed in accordance with the Consolidated Standards of Reporting Trials 2010 (CONSORT) statement. The two arms of the study included a multimodal non-opioid pain regimen for the experimental group, and a standard of care narcotics for the control group. The primary outcome was visual analog scale (VAS) pain scores for the first ten postoperative days. Secondary outcomes included PROMIS-PI, patient satisfaction, and adverse drug events. Patients were randomized using a random number generator. Whiles patients were not blinded to their treatment group, all reported outcomes were collected by blinded observers. Results Twenty-six patients either declined to participate or were excluded from the study. Forty-four patients were included in the final analysis. A total of 27 patients were in the traditional group and 17 patients were in the nonopioid group. Patients in the traditional pain control group reported a significantly lower VAS pain score on post-operative day 1 (opioid: 5.7 ± 2, nonopioid: 3.7 ± 2.2, p=0.011) and post-operative day 4 (opioid: 4.4 ± 2.7, nonopioid: 2.4 ± 2.2, p=0.023). No significant difference was seen on any other postoperative day. When mixed measured models were used to control for confounding factors the non-opioid group demonstrated significantly lower VAS and PROMIS-PI scores (p<0.01) at every time point. The most commonly reported side effects for patients in both groups were drowsiness (opioid: 2.7 ± 3.3 days, nonopioid: 1.9 ± 3.3 days) and constipation (opioid: 2.2 ± 2.9 days, nonopioid: 0.2 ± 0.6 days). Patients in the traditional analgesia group reported significantly greater average number of days with constipation (opioid: 2.2 ± 2.9, nonopioid: 0.2 ± 0.6, p=0.003) and days with upset stomach (opioid: 1.3 ± 2.5, nonopioid: 0.0 ± 0.0, p=0.020) than those in the nonopioid group. Conclusions This study found that a multimodal nonopioid pain protocol provided at least equivalent pain control compared to traditional opioid analgesics in patients undergoing primary arthroscopic rotator cuff repair. Minimal side effects were noted with some improvement in the multimodal nonopioid pain cohort, and all patients reported satisfaction with their pain management.

Objectives From both a patient’s and clinician’s perspective, interpreting numeric values from patient reported outcome measures (PROMs) is not always straightforward to evaluate “success” of surgery. To better address this dilemma, a single validated question related to a patient’s acceptable symptom state (“PASS”) has been recently developed and incorporated into outcome studies. The question reads “Taking into account all the activity you have during your daily life, your level of pain and also your activity limitations and participation restrictions, do you consider the current state of your knee satisfactory? (yes/no)”. The study objective was three-fold. First, to determine what percentage of ACL reconstructed patients responded “yes” to the PASS question at 10 years following their index surgery. Second, to correlate PASS with IKDC, KOOS Pain, and Marx activity level scores. Third, to predict what variables lead to a patient saying ‘no’ on the PASS. Methods As part of a longitudinal cohort, patients were asked to complete the PASS question in addition to completing other PROMs (IKDC, KOOS, and Marx activity level) at their 10-year follow-up. Continuous variables such as age, BMI, IKDC, KOOS Pain, and Marx at 10 years were summarized using medians and interquartile ranges (IQR). Categorical variables such as sex, smoking status, and meniscus treatment were summarized using counts and percentages. IKDC, KOOS Pain, and Marx at 10 years were compared between those who achieved an acceptable state and those who did not achieve an acceptable state using the Wilcoxon rank-sum test. A multivariable logistic regression model was built to predict who would fail to achieve patient acceptable state at 10 years follow-up. The predictors in the model included age at baseline, sex, BMI at baseline, and subsequent surgery. Model results were displayed using odds ratios, 95% confidence intervals and p-values. Data management and data analysis were performed using R software (Version 4.0; Vienna, Austria). All tests were two-sided, with an alpha level of 0.05. Results A total of 325 patients (median age of 23 years; 155 [48%] males) completed the PASS survey. Of these, 87% (282/325) reported achieving a patient acceptable state, while 13 (43/325) did not achieve an acceptable state. Figure 1 shows the comparisons of the 10-year IKDC, KOOS Pain, and Marx between the two groups. All comparisons are statistically and clinically significant, suggesting that the median scores at 10 years are significantly lower in patients who did not achieve an acceptable state compared with those who did. The patients who reported not having an acceptable state (PASS=no) were 36.8 points worse on IKDC, 22.2 points worse on KOOS Pain, and 5.5 points lower on their Marx activity level scores. Multivariable regression analysis found that patients who had any subsequent surgery following their index ACL reconstruction were 2.5 times more likely to report an unacceptable patient symptom state (PASS=no) at 10 years (Table 1). Patient age, sex and BMI were not found to be significant risk factors. Conclusions A high percentage of patients (87%) remain satisfied with their knee 10 years following their index ACL reconstruction. Large clinically relevant and statistically significant differences were observed on PROMs between those patients who answered “yes” versus “no” on PASS. The major risk factor for not being satisfied with their knee was having any subsequent surgery prior to a patient’s10-year assessment. [Figure: see text][Table: see text]

Objectives Suprascapular neuropathy due to nerve compression or tension at the suprascapular notch is an uncommon source of shoulder pain and rotator cuff weakness with recent increased recognition and treatment. Long considered an elusive diagnosis, work-up can be lengthy and patients may experience treatment delay. We aimed to review presentation patterns and outcomes of arthroscopic suprascapular nerve decompression in a predominantly young and active military population. Methods The surgical databases of two surgeons were queried for patients treated with arthroscopic suprascapular nerve decompression at the suprascapular notch from 2013 to 2021. Patient data, presentation and workup findings, and outcome measures were collected through review of the electronic medical record. Primary outcome measures were rate of return to active-duty military service, shoulder abduction and external rotation strength, and VAS pain scores. Secondary outcome measures were American Shoulder and Elbow Surgeons (ASES) Shoulder Score, Visual Analogue Scale (VAS), and Single Assessment Numerical Evaluation (SANE) score. Results Twenty-five patients were identified. Average age was 26.6 years and follow-up 17.9 months (4-62 months). There were two distinct primary presentation types in this cohort: the chief complaint was pain in 13 patients (52%) and weakness in 12 (48%). Supraspinatus and/or infraspinatus atrophy was present on MRI in 10/12 patients with weakness and 0/13 with pain. Electromyography was positive in 9/12 with weakness and negative when obtained in 5 patients with pain. Ultrasound-guided suprascapular nerve injection was performed in 10/13 with pain and provided mean 91% symptom relief. Patients with pain had longer duration of pre-operative symptoms (22.2 [±13.1] vs. 10.3 [±13.6] weeks). Postoperatively, the pain group had significant improvement in VAS scores (6.2 [±1.6] to 1.0 [±0.9]), while the weakness group had significant improvement in abduction and external rotation motor grading (3.7 [±0.7] to 4.7 [±0.4] and 3.3 [±0.8] to 4.4 [±0.6] respectively). Return to duty or sport was 92% at a mean of 14.6 (±9.3) weeks. Conclusions In this young, active cohort, suprascapular neuropathy presented with one of two distinct primary presenting complaints: pain or weakness. Given different expected work-up findings, categorizing patients into one of these two groups may be beneficial in effectively diagnosing and treating suprascapular neuropathy. Outcomes after arthroscopic suprascapular nerve release at the suprascapular notch predictably led to successful pain relief and strength improvement in patients presenting with pain and weakness respectively. [Table: see text][Table: see text]

Objectives Patellar instability is estimated to affect approximately 150 out of 100,000 adolescents between the age of 14-18 years old, a rate which is expected to increase over time. Several risk factors have been associated with patellar instability such as younger age, trochlear dysplasia and patella alta. Patella alta is defined as a superiorly-positioned patella, commonly determined using the Caton-Deschamps Index (CDI), with a ratio of 1.3 or greater indicative of patella alta. Patients with patella alta are approximately 2.5-4.0 times more likely to suffer a recurrent patellar dislocation, which is thought to be due to the changes in biomechanics seen in patella alta. Differences in chondral injury in patients with patellar instability between patella alta and patella norma has not been evaluated. Our objective was to retrospectively analyze whether preoperative cartilage damage differs in severity and location between patellar instability patients with and without patella alta. Methods Patients with patellar instability who underwent patellar realignment surgery at a single institution with a preoperative MRI within 3 months were included. After measurement of CDI on MRI, patients were divided into patella alta (CDI>1.3) and patella norma groups. To quantify cartilage defect severity, the Magnetic Resonance Imaging Score and Classification system (AMADEUS) was utilized by two sports medicine clinical fellows. The AMADEUS score characterizes cartilage defect size, defect depth, presence of subchondral bone defects, and bone marrow edema. The scale is scored 0-100 with 100 indicating no cartilage damage. In patients with multiple cartilage defects on MRI, each defect was characterized and analyzed independently. Continuous variable data were reported as means with standard deviations and categorical data reported as frequencies with percentages. The distribution of data was assessed with the Shapiro-Wilk test. Continuous data were assessed with the Student’s t test and Mann-Whitney U tests as appropriate. Categorical data were assessed with chi-squared analysis. The threshold for significance was set to p < 0.05. Multivariate analysis was conducted with defect depth, bone edema, and AMADEUS score as the dependent variable. All statistical analyses were performed with R Studio (Version 3.6.3, Vienna, Austria). Results One hundred-twenty-one patients were divided into patella alta (n=50) and patella norma (n=71). The groups did not significantly differ in sex ratio, age at MRI, body mass index (BMI), mean reported number of prior dislocations, or mean interval between first reported dislocation and date of MRI. Thirty-four (68%) of the patella alta group and 44 (62%) of the patella norma group had chondral defects ( P=0.625) with no statistically significant difference in the size of the chondral defects between the groups ( P=0.419). In both groups, chondral injuries most affected the medial patellar facet (55% in patella alta vs. 52% in patella norma), followed by the lateral facet (25% vs 18%), and lateral femoral condyle (10% vs 14%)( P=0.859). The patella alta group had a smaller proportion of patients who had full thickness defects in comparison to the patella norma group (60% vs 82%; P=0.030). The overall AMADEUS score for the patella alta group was higher (68.9 vs. 62.1; P=0.023) compared to the patella norma group, indicating superior articular cartilage status. When looking at a multivariate regression using AMADEUS score as the dependent outcome, female sex shows an increase in AMADEUS score with a beta estimate of 11.96 ( P<0.001). Female sex also shows a higher probability of having no defect associated bone marrow edema (Odds ratio:6.7; P=0.010), and a higher probability of partial-thickness defect rather than full-thickness (Odds ratio:3.9; P=0.004). Age, BMI, interval between dislocation and MRI, and reported number of dislocations were not found to be associated with total AMADEUS score, probability of having defect-associated bone marrow edema, or defect depth. Conclusions There is a high percentage of cartilage injury in patients with a history of patellar instability with over 60% of patients showing cartilage damage on MRI. Patients with normal patellar height have a higher frequency of full thickness cartilage defects and more severe injury compared to those with patella alta. The location of cartilage injury between alta and norma is similar, with most defects affecting the medial facet, lateral facet, and lateral femoral condyle in descending frequency.

Objectives It is unclear if concomitant glenohumeral osteoarthritis is protective or detrimental with respect to rotator cuff integrity after arthroscopic repair surgery. We hypothesized that the associated stiffness might protect the repaired tendon. In the alternate, arthritis might reflect a gradual degeneration of the joint including a degenerative tendon and therefore predispose the repair to re-tear. Therefore, the purpose of this study was to investigate whether concomitant osteoarthritic changes found intra-operatively during arthroscopic rotator cuff repairs (RCR) have a beneficial or detrimental effect on post-operative repair integrity. Methods This study is a post-hoc analysis of prospectively collected data of patients who underwent primary arthroscopic RCR between 2005 and 2019 by a single surgeon. Patients were divided into an osteoarthritic group and a control group based on the presence or absence of intra- operative osteoarthritic changes respectively. The primary outcome measure was cuff integrity detected by post-operative ultrasound at 6-months. The secondary outcomes were patient-reported outcomes including shoulder pain, stiffness, level of activity at work and level of sport, and physician-reported outcomes including shoulder range of motion and strength. Results A total of 2155 consecutive patients met the inclusion criteria with a mean age of 59 years (SD=0.2) and there were more males as compared to females (56% vs. 44%). 28% of patients undergoing RCR had osteoarthritic changes detected intra- operatively. Intra-operatively, the osteoarthritic group had more full-thickness tears (64% vs. 59%) (p<.001), a larger mean anteroposterior tear length [20mm (SD=0.5) vs. 17mm (SD=0.4)] (p<.001) and a larger mean mediolateral tear length [17mm (SD=0.5) vs. 15mm (SD=0.4)] (p<.001). Ultrasonographic evaluation at 6-months post-surgery demonstrated that the osteoarthritic group had a higher incidence of cuff re-tear rate as compared to the control group (15% vs. 11%) (p=.016) ( Figure 1). However, after performing a multiple logistic regression analysis, osteoarthritis was not found to be an independent predictor of re-tear. There were very marginal differences in patient-reported outcomes at 6-months after surgery between the two groups ( Table 1). The osteoarthritic group reported lesser post-operative frequency of activity pain [2.0 (SD=1.46) vs. 2.2 (SD=1.43)] (p=.005), frequency of extreme pain [0.8 (SD=1.35) vs. 1.0 (SD=1.41)] (p=.035) and level of pain during overhead activity [1.7 (SD=1.30) vs. 1.9 (SD=1.30)] (p=.021) as compared to controls. As compared to controls, the osteoarthritic group also experienced lesser post-operative stiffness [1.5 (SD=1.32) vs. 1.6 (SD=1.31)] (p=.019) and reported lower intensities of work-related activities [1.1 (SD=0.88) vs. 1.2 (SD=0.85)] (p=.038) and lower level of sport activity [0.4 (SD=0.62) vs. 0.5 (SD=0.70)] (p=.004). In terms of physical examination at 6-months following surgery ( Table 2), the osteoarthritic group were found to have lesser range of motion in forward flexion [146° (SD=33.1) vs. 151° (SD=31.2)] (p=.009), abduction [127° (SD=38.8) vs. 131° (SD=38.1)] (p=.034), external rotation [50° (SD=21.4) vs. 52° (SD=21.0)] (p=.024) and internal rotation (L1 vertebrae (SD=4.2) vs. T12 vertebrae (SD=4.2)] (p=.004) as compared to controls. The osteoarthritic group as weaker internal rotation strength [68N (SD=30.5) vs. 73N (SD=32.9)] (p=.004), external rotation strength [57N (SD=25.3) vs. 60N (SD=27.2)] (p=.026), supraspinatus flexion strength [45N (SD=26.8) vs. 50N (SD=27.9)] (p<.001), lift-off [40N (SD=24.3) vs. 44N (SD=25.3)] (p<.001) and adduction strength [76N (SD=36.5) vs. 81N (SD=39.3)] (p=.008) as compared to the control group. Conclusions Patients with concomitant glenohumeral osteoarthritis who underwent arthroscopic RCR had higher re-tear rates at 6-months after surgery. However, osteoarthritis is not an independent predictor of rotator cuff re-tear at 6-months. Therefore, arthroscopic RCR is a viable surgical option for these patients. [Figure: see text][Table: see text][Table: see text]

Objectives During the 21 st century, opioid medication prescription and consumption has increased, which has led to an increase in opioid abuse, dependence, and fatal overdoses. Health care providers, particularly surgeons, have recently focused on decreasing the amount of opioids prescribed, as overprescribing is a known cause contributing to the opioid epidemic. Patients undergoing anterior cruciate ligament reconstruction (ACLR) would especially benefit for the identification of an ideal opioid prescription amount for post-op pain, as the average age of patients undergoing ACLR is 29.8 years old, which falls within the age group that experienced the largest increase in opioid related deaths between 2001 and 2016. It is unknown if prescribing patterns change patient behavior related to opioid consumption. The purpose of this randomized, prospective trial was to evaluate the effects of different quantities of prescribed opioid tablets on opioid utilization by patients, post-operative pain, and patient satisfaction following ACL reconstruction. Methods This study was a prospective, randomized trial enrolling patients undergoing primary ACLR following ACL tear. Patients were randomly assigned to one of 3 prescription groups pre-operatively: 15 tablets, 25 tablets, or 35 tablets of oxycodone-5mg. Standard of care nerve blocks were utilized in all patients in addition to general anesthesia for the surgical procedure. Patients were instructed to take acetaminophen and NSAIDs as needed with the opioid medication to be used for “breakthrough” pain. Exclusion criteria included concomitant procedure other than meniscectomy or meniscal repair, ACL revision, history of chronic pre-operative opioid use, history of substance abuse, pregnancy, or workman’s compensation claims. Patients in all 3 groups were asked to complete pain and medication logs 2 times a day for the first 14 days post-operatively, along with an opioid medication satisfaction survey at 2 weeks, and IKDC questionnaires before surgery and up to 6 months post-operatively. Demographics and complication information were gathered from the medical record. Requests for prescription refills were recorded as well. Analysis assessed for statistical differences in post-op pain and medication usage. All usage of narcotics was verified with the state database monitoring system for narcotic pain medication. Results One hundred thirty patients were included in the analysis (41 who received 15 oxycodone tablets, 40 who received 25 oxycodone tablets, and 49 who received 35 oxycodone tablets). There were no significant differences between the two groups in mean age at surgery (33.6 vs. 31.6 vs 33.3; P=0.328), BMI (27.7 vs 26.1 vs 25.7; P=0.525), or sex ratio (24M/17F, 20M/19F, 25M/24F; P=0.735). There were also no significant preoperative differences in subjective pain and function, as measured by IKDC scores (46.8 vs 48.7 vs 46.5; P=0.794). There were no significant differences in mean total morphine milligram equivalents (MME) consumed between the three groups (72.3 in the 15 tablet group, 61.9 in the 25 tablet group, 78.1 in the 35 tablet group; P>0.05). There was a significant difference between those who received 15 tablets and those who received 25 and 35 tablets when asked if they thought they were prescribed too few/too many narcotics, with a greater percentage of the 15 tablet group reporting that they felt they received too few at 20.6%, (P=0.05) as depicted in Figure 1. Despite this difference, there was no significant difference between the three groups on subjective morning or afternoon pain for the first 14 days after surgery, total opioid pills consumed, patient satisfaction on ability of the narcotic to treat their condition, patient satisfaction on amount of pain relief they experienced since surgery, or patient satisfaction regarding the amount of narcotics initially prescribed after surgery. Finally, there was no difference between the three groups on postoperative function at 2 weeks, 6 weeks, 3 months, and 6 months, as measured by IKDC scores (Figure 2). Conclusions Despite a significantly larger portion of the group who received 15 oxycodone tablets reporting that they felt they received too few opioid tablets, there was no difference between those who received 15, 25, or 35 oxycodone-5mg tablets in reported pain levels, opioid consumption, or any satisfaction metrics. In addition, there was no difference between the three groups in pain and function as reported in the IKDC surveys. Given these results, giving lower quantities of opioid medication appears to be as effective in appropriately controlling post-operative pain as higher quantities, and may help to limit amount of opioids prescribed and possible diversion of unused prescription opioid medication. [Table: see text]

Objectives The incidence of long head of the biceps tendon (LHBT) procedures is increasing, yet the role of the LHBT in glenohumeral stability is not fully understood. People lift most objects in the sagittal plane with forward flexion, which stresses the posterior aspect of the unconstrained glenohumeral joint. Determining the mechanism by which the shoulder maintains stability with functional motions is important to understanding the pathoanatomy of degenerative shoulders. We hypothesize that the LHBT resists posterior translation of the humeral head (HH) during forward flexion by tensioning the posterior capsuloligamentous complex. Methods Ten fresh-frozen cadaveric shoulders were tested using an established shoulder simulator, which loads the rotator cuff, deltoid and LHB tendons through a system of pulleys and weights. A motion tracking system recorded glenohumeral translations with an accuracy of ±0.2mm. In each subject, the scapula was fixed and the humerus was tested in 6 positions: 30 and 60 degrees of glenohumeral forward flexion at i) maximum internal rotation (IR), ii) neutral rotation and iii) maximum external rotation (ER) (Figure 1). The deltoid was loaded with 100N, and the infraspinatus and subscapularis were loaded with 22N each. The difference in glenohumeral translation was calculated at each position comparing the LHBT loaded with 45N or unloaded. Results When comparing the two states of LHBT loading vs unloading, unloading the LHBT led to an overall increase in posterior and superior translation of the humeral head (Figure 2) in all tested positions (neutral, maximum internal rotation, maximum external rotation in both 30 and 60 degrees of forward flexion). At 30 degrees of glenohumeral forward flexion, unloading the LHBT increased HH posterior translation by 2.46mm (±0.92mm) (p<0.001), 1.71mm (±1.02mm) (p<0.001) and 1.02mm (±0.88mm) (p=0.014) at maximum ER, neutral rotation, and maximum IR, respectively (Figure 3). At 60 degrees of glenohumeral forward flexion, unloading the LHBT increased HH posterior translation by 2.77mm (±1.16mm) (p<0.001), 2.43mm (±1.56mm) (p<0.001) and 1.66mm (±1.42mm) (p<0.001) at maximum ER, neutral rotation and maximum IR, respectively (Figure 4). Unloading the LHBT led to more posterior translation at 60 degrees of glenohumeral forward flexion compared to 30 degrees (p=0.013). Conclusions LHBT loading resists posterior translation of the humeral head during forward flexion. This data supports the role of the LHBT as a posterior stabilizer of the shoulder, specifically when a person is carrying objects in front of them. Biceps tenotomy or tenodesis may contribute to microinstability of the glenohumeral joint and shift contact pressure posteriorly. Further work is needed to determine if unloading the LHBT, as is done with biceps tenotomy or tenodesis, may eventually contribute to the posterior glenoid wear seen with osteoarthritis.

Objectives Pain is a common presentation following glenohumeral labral injuries. However, the source of that pain is undetermined. We aimed to determine if there is a differential expression of nerve fibres around the glenoid labrum and if torn labra have increased neuronal expression compared to untorn labra. Methods Labral tissue was collected at 3, 5, 9 and 12 o clock during total shoulder arthroplasty (n = 7). Samples were also collected at 3, 5 and 12 o clock during rotator cuff repair (n = 16), anterior labral repair (n = 6), type II superior labral anterior to posterior (SLAP) repair (n = 4) and capsular release for idiopathic capsulitis (n = 5). Sections were immunostained with antibodies to neurofilament, a specific neuronal marker which is used to identify central and peripheral nerve fibres, and the concentration and intensity of immunostained-positive cells assessed. Results The concentration of neurofilament staining was similar in the superior, anterior, posterior and inferior glenoid labrum in untorn labra (8 neurofilament expressing cells/mm ² , p > 0.05). Torn labra exhibited a 3-4-fold increase in neuronal expression which was isolated to the location of the tear in SLAP (p = 0.09) and anterior labral tears (p = 0.02). The concentration of neurofilament expressing cells in torn glenoid labrum samples were comparable to the glenoid labrum of adhesive capsulitis samples (p > 0.05). Figure 3. Mean (SD) neurofilament expressing cells per mm ² at 12 o’clock (A), 3 o’clock (B) and 5 o’clock (C) using labral tissue from patients with either a; RCT (n = 16), anterior labral tear (n = 6), SLAP tear (n = 4) or a frozen shoulder (n = 5). *p <0.05 compared using a one-way ANOVA with post-hoc analysis. Conclusions This study supports the hypothesis that following a traumatic tear of the anterior or superior labrum, the labrum in that region becomes populated with new nerves fibres and that these fibres are likely to be responsible for many of the symptoms noted by patients with superior (SLAP) and/or anterior labral (Bankart) tears.

Objectives Patellar dislocations are associated with a high risk of patellofemoral osteoarthritis (OA). The risk is further elevated for adolescent patients and patients who experience multiple dislocations. Quantitative MRI using T1ρ relaxation time mapping characterizes cartilage properties based on concentration of proteoglycans. Elevated T1ρ values identify cartilage degradation that could develop into post-traumatic OA. The current study compares T1ρ relaxation times throughout the knee between adolescents being treated for a single dislocation, multiple dislocations, and healthy controls. The hypothesis of the study is that patellar dislocation will increase T1ρ relaxation times for patellofemoral cartilage, with higher T1ρ relaxation times for multiple dislocations than single dislocations. Methods The IRB-approved study included 13 patients (16 ± 2 years; 5 females; BMI: 23 ± 3 kg/m ² , 47 ± 38 days since dislocation) being treated for an initial, unilateral traumatic lateral patellar dislocation, 10 being treated for multiple unilateral dislocations (17 ± 2 years, 2 females; 23 ± 4 kg/m ² , 55 ± 24 days since most recent dislocation), and 10 healthy controls (16 ± 2 years, 5 females; 22 ± 2 kg/m ² ). MRI scans included a 3D water excitation dual energy steady state (DESS) scan of the knee for segmentation of cartilage surfaces (slice thickness of 0.7 mm) and a T1ρ relaxation time scan (fat saturated scan, slice thickness = 4 mm, spin lock times = 0, 10, 40, and 80 ms, spin-lock frequency = 500 Hz). Automated algorithms based on machine learning were used to automatically segment cartilage into six compartments: patella, trochlear groove, lateral/medial femur, lateral/medial tibia. The cartilage on the patella and within the trochlear groove were further divided into medial, lateral and central regions. The central region was centered on the patellar ridge for the patella and the deepest points throughout the trochlear groove and extended one-third of the distance to the medial and lateral edges. Additional automated algorithms mapped T1ρ relaxation times to the reconstructed cartilage surfaces (Fig. 1). Mean T1ρ relaxation times were quantified within each region for each knee. The mean T1ρ relaxation times within the regions were compared between the three groups with ANOVA’s and Student-Newman-Keuls post-hoc tests. Statistical significance was set at p < 0.05. Results T1ρ relaxation times were significantly longer for injured knees (both single and multiple dislocations) than controls at the medial and central patella, central trochlear groove, and lateral tibia (Fig. 2). For regions on the patella, the significant differences represented a difference between injured and control knees of 20% or larger. For the other significant regions, the difference was approximately 10%. No significant differences were identified between single and multiple dislocations. Conclusions For adolescent patients, a patellar dislocation is associated with elevated T1ρ relaxation times for cartilage throughout the knee. Elevated T1ρ values indicate loss of proteoglycan content that reduces cartilage integrity and could be an initiation point for progression to OA. Elevated relaxation times from quantitative MRI is consistent with previous studies focused on patellar dislocations. The current study uniquely focuses on an adolescent population and uniquely compares single to multiple dislocations in the acute phase following injury. The results set a baseline for characterization of progressive cartilage degradation to OA following patellar dislocation for adolescents. The elevated T1ρ relaxation times within the patellofemoral joint are consistent with high risk of long term patellofemoral OA for adolescents who experience patellar dislocations. The elevated T1ρ relaxation times at the lateral tibia indicate an additional risk of tibiofemoral OA. The similar T1ρ relaxation times for single and multiple dislocations was not expected due to the higher risk of patellofemoral OA following multiple dislocations. Traumatic impact of the medial patella against the lateral femoral condyle during a dislocation is a primary contributor to cartilage degradation in the acute phase following a patellar dislocation, as demonstrated by the largest difference between injured knees and controls occurring at the medial patella for first time dislocators. Additional dislocations did not further increase T1ρ relaxation times at the medial patella. Recurrent dislocations could be less traumatic due to previous injury to medial soft tissue restraints, decreasing the influence on cartilage properties. Inflammation and pathologic anatomy can also contribute to cartilage degradation in adolescents experiencing patellar dislocations. Traumatic injury induces an inflammatory response that can be detrimental to cartilage. Pathologic anatomy associated with patellar dislocations includes patella alta, trochlear dysplasia and a lateral position of the tibial tuberosity. Pathologic anatomy can create loading conditions during daily function that adversely influence cartilage. Inflammation and anatomy likely contribute to the significantly elevated T1ρ relaxation times away from the medial patella. Over the long term, inflammation and anatomy may play a greater role in the risk of OA for multiple dislocators than repeated impact injuries. To continue to characterize the continuum from patellar dislocation to OA, additional recruitment is warranted to determine if significant differences can be identified in additional regions. Additional characterization of the influence of inflammation and pathologic anatomy on cartilage degradation is also warranted to identify patients at highest risk of OA and develop treatment strategies to preserve cartilage following patellar dislocations. [Figure: see text][Figure: see text]

Objectives Nonoperative management of posterior shoulder instability is common, however there is limited data available to assess the pathomorphology of nonoperative management. The purpose of this study is to evaluate glenohumeral pathomorphology in shoulders with posterior glenohumeral instability treated nonoperatively. Methods We conducted a retrospective review of a consecutive series of patient with isolated posterior shoulder instability defined as an isolated posterior labral tear with a corresponding positive Jerk or Kim test. Patients were excluded if they had prior shoulder surgery or absence of a Jerk or Kim test. Non-operative management was defined as a trial of formal physical therapy pursuit of nonsurgical modalities for a minimum 6 months. Patients who underwent non-operative management and subsequently had a repeat MRI of the initially injured shoulder were identified, and the two studies were compared to evaluate for changes in glenoid bone loss, glenoid morphology, cartilage injuries, and the presence of concurrent pathology. Our primary outcome was glenoid changes associated with failure of non-operative management, which was defined as reoperation and/or medical separation from the military due to the injured shoulder. Secondary outcomes included evaluation of potential risk factors for failure of non-operative management including glenoid bone loss, glenoid version, and posterior humeral head subluxation. Continuous variables were compared with student’s t-test or Fisher exact test when appropriate. Categorical variables were analyzed using Chi-squared. Multivariable regression analysis was used to evaluate risk factors for failure. Results 42/90 (46.7%) patients failed a 6-month trial of nonoperative management after being diagnosed with posterior glenohumeral instability and went onto receive an arthroscopic stabilization procedure. The failure group demonstrated a significantly greater humeral head subluxation ratio than the cohort of patients who survived nonoperative management (0.65 ± 0.2 vs 0.62 ± 0.2; p = 0.0375). Of those who failed nonoperative management only 17 had repeat MRI’s for comparison with initial MRI’s, which revealed a significantly greater increase in glenoid bone loss (6.54 ± 1.59 vs 2.68 ±1.71; p = 0.00274). The mean time from index MRI and repeat MRI was 488 days (95% CI 317 to 658). Conclusions In patients that underwent 6-months of nonoperative management for isolated posterior glenohumeral instability, failure occurred approximately 47% of the time and was associated with a greater posterior humeral head subluxation ratio on index MRI than those who did not fail. Additionally, those who had repeat MRI on average 1.3 years later demonstrated greater glenoid bone loss when compared to the index MRI.

Objectives Accuracy of femoral tunnel positioning is critical during medial patellofemoral complex (MPFC) reconstruction, as even 5mm of malpositioning has been associated with altered patellofemoral contact pressures. To help identify the appropriate position for femoral tunnel placement, Schottle and others have described radiographic landmarks to identify the MPFC footprint on lateral knee radiographs. These measurements are based on an extension of the posterior cortical line, which can vary based on the length of the femur visible on the radiograph. Because the scope of view can vary between intraoperative imaging modalities, the aim of this study was to assess the effect of femoral length on the accuracy of radiographic landmarks of the MPFC. Methods In 9 unpaired cadaveric knees, the MPFC footprint was exposed on the medial femur, and the proximal and distal boundaries of the footprint were marked. Lateral fluoroscopic images of the knee were obtained and assessed in 1 cm length increments, beginning 1cm proximal to the posterior condyle and continuing proximally to a femoral length of 8 cms. The MPFC midpoint was described on each image relative to the posterior cortical line of the femur and a line perpendicular to this line, relative to the proximal margin of the posterior condyle. Linear regression analysis was used to assess the effect of femoral length on the radiographic position of the MPFC. ROC curve analysis and Delong test were used to determine ROC curve analysis and Delong test were used, and the minimum amount of femoral length required on radiographs to accurately identify an anatomic femoral tunnel was determined using Youden’s J statistic. Results Using the posterior cortical line as a reference, the radiographic description of the MPFC footprint moved anteriorly with decreasing femoral length on the radiographs, particularly at 4cm and less. However, no proximal-distal change was seen in relation to the line through the proximal margin of the posterior condyle with changing femoral lengths. Linear regression analysis showed a significant relationship between the femoral length and anterior position of the MPFC on radiographs (R = 0.461, R ² = 0.212, B= -0.636, p < 0.001). The slope coefficient was -0.636 mm, indicating that for every cm decrease in femoral length, the actual anatomic footprint of the MPFC moves anteriorly by 0.636 mm in relation to the posterior cortical line. Furthermore, ROC curve analysis revealed that a minimum of 4 cm of femoral length on lateral radiographs is required to accurately localize the footprint of the MPFC (AUC 0.79; sensitivity 76.7 %; specificity 69 %; p < 0.001). Conclusions The radiographic landmarks for the MPFC femoral footprint can change depending on the length of the distal femur visible on radiographs. We found that at least 4cm of the femoral shaft should be visible for the radiographic landmarks to be accurate. As fluoroscopy is frequently used intraoperatively for MPFC reconstruction, our findings may serve as a guide for accurate femoral tunnel placement.

Objectives While it is well-known that a glenoid osseous defect of >25% glenoid width or 20% of the glenoid length critically destabilizes the shoulder, it is unclear whether glenoid cartilage defects contribute to the shoulder stability, and if so at what size defect the shoulder is critically destabilized. The purpose of this study was to determine the effect of incremental cartilage defect sizes on the anterior shoulder stability. We hypothesized that cartilage defects of equal to or greater than 25% of the glenoid width or 20% of the glenoid length will significantly the decrease the anterior shoulder stability ratio. Methods This was a controlled laboratory study testing 12 fresh-frozen shoulders. Specimens were attached to a custom testing device in abduction and neutral rotation with 50N compression applied to the glenoid. The humeral head was translated 10 mm anteriorly, anteroinferiorly, and anterosuperiorly with conditions of intact cartilage and labrum and anterior cartilage defects of 3, 6, and 9 mm width. Translation force was measured continuously. Peak translation force divided by 50 N compression force was defined as the stability ratio. Data were analyzed using ANOVA tests. Results In the anterior direction, the stability ratio decreased between intact cartilage (36±7%) and all defects 3-mm or larger (32±8%, p=0.023.) In the anteroinferior direction, the stability ratio decreased between intact cartilage (52±7%) and all defects 3-mm or larger (47±7%, P=0.006). In the anterosuperior direction, the stability ratio decreased between intact cartilage (36±4%) and all defects larger than 6-mm (32.6±4%, P = 0.006.) A 3-mm cartilage defect was equivalent to 10% of the glenoid width and 7% of the glenoid length. There were strong negative correlations between the glenoid cartilage defect size and the stability ratio in the anterior direction, the anteroinferior direction and the anterosuperior direction (r= -0.79, -0.63, and -0.58, respectively, P≤0.001). There were strong negative correlations between the ratio of glenoid cartilage defect size to the glenoid width and the stability ratio in all directions (r= -0.81, -0.63, and -0.61, respectively, P≤0.001.) Conclusions An anterior cartilage defect of >3 mm or >10% of the glenoid width or 7% of the glenoid length significantly decreases anterior and anteroinferior stability and may require further treatment to restore stability. Cartilage defect size negatively correlates with stability.

Objectives The purpose of this study is to identify clinical and radiographic factors that predict return to sport in high-level athletes and to determine thresholds for significant predictors. Methods Data were reviewed on all patients who underwent primary hip arthroscopy between November 2008 and August 2018. Patients were included if they played professional, college, or high school sports within 1 year before surgery and had preoperative, 3-month, 1-year, and 2-year postoperative patient reported outcome (PRO) scores for modified Harris Hip Score (mHHS), Hip Outcome Score-Sport Specific-Subscale (HOS-SSS), and Non-Arthritic Hip Score (NAHS). Patients were divided into groups based on whether they returned to sport (RTS). Multivariate logistic regression and receiver operator characteristic (ROC) analysis were used to evaluate the correlation between significant variables and RTS. Results A total of 136 patients with a mean age of 20.8 ± 7.07 years were included. Competition level, postoperative alpha angle, change in alpha angle, and postoperative PROs were significantly different between groups. The multivariate logistic regression model identified postoperative alpha angle as a statistically significant predictor of return to sport [P < .001, S > 9.97 (OR 0.85, CI 0.79-0.91)]. The ROC curve for postoperative alpha angle demonstrated acceptable discrimination between patients returning to sport and patients not returning to sport with an area under the curve of 0.71 and a threshold value of 46˚. Athletes with a postoperative alpha angle ≤ 46˚ returned to sport at a rate of 71.2%, while those with a postoperative alpha angle > 46˚ returned to sport at a rate of 28.1% [(P < .001, S > 9.97 (OR 6.3, CI 2.6-15.2)] Conclusions Postoperative alpha angle was identified as a predictor of return to sport in high-level athletes. The odds of returning to sport were 6.3 times greater in athletes with postoperative alpha angles ≤ 46˚ compared to athletes with angles > 46˚.

Objectives Arthroscopic correction of FAI is a powerful way to improve pain and function in athletes and patients. Surgeons learning hip arthroscopy experience a learning curve while gaining competence. The objective of the present study was to evaluate the learning curve in hip arthroscopy for FAI according to improvements in patient-reported outcome instruments. Methods A retrospective review was performed of a single surgeon’s first 1000 hip arthroscopy cases during their first 4 years in practice. Arthroscopy cases that occurred concurrently with PAO or femoral osteotomy (n=360) were excluded. Convenience samples (n=50) were taken from each year in practice. Pre-operative and post-operative HOOS- Pain and HOOS-physical function scores were obtained. Linear trends were assessed, and cutoffs for MCID for HOOS (10 points) were surveyed across time. Students t tests were used for continuous variables and chi squared tests were used for categorical variables and significance was set to p<0.05. Results During the first 250 cases, a sample of patients was obtained (n=50), and 11/50 did not meet MCID (22%) for HOOS Pain at 1-year follow-up. A convenience sample of cases subsequent to this from cases 251-1000 (n=100) 11/100 after that did not meet MCID (11.0%, p<0.05). The mean 1-year postop HOOS Pain score for year 1 was 82.77, year 2 was 90.56, year 3 was 89.34 and year 4 was 93.48 (P<0.05). Delta HOOS Pain of PS did not change over time, p>0.05). For both HOOS Pain and Physical Function subscales, 1-year postop scores continued to improve over the 4-year 1000-case study period (graph). Conclusions According to the HOOS validated patient reported outcome instrument, the learning curve for significant benefits in hip arthroscopy is between 130-250 cases. Many patients (almost 80%) saw significant clinical benefit during the learning curve, however the quality of outcome was significantly improved after 250 cases. 1-year post-op PROs appear to continually improve even after cases 750-1000

Objectives Though recognized as a risk factor, posterior glenoid bone loss has only recently been characterized and is distinctly different than anterior glenoid bone loss patterns. Existing biomechanical studies are limited by employment of anterior glenoid bone loss models which are different in both orientation and morphology than posterior glenoid bone loss, and testing in a single neutral arm position thus not fully accounting for the contribution of capsuloligamentous structures in various at-risk arm positions. The purpose of this study was to evaluate the biomechanical effectiveness of a posterior labral repair in the setting of a clinically relevant bone loss model using 3-dimensional computed tomography modeling of patients with recurrent posterior shoulder instability in various at-risk arm positions. Methods Ten fresh-frozen cadaveric shoulders (mean age: 55.4 years, range: 39-65) were prepared by removing all tissue except the capsule and distal rotator cuff insertions. A joint coordinate frame was established, the specimens were potted, then mounted to a customized fixture on 6-degrees-of-freedom robotic arm. A posterior labral tear was created, then repaired with 3 horizontal mattress sutures and secured by drilling 6 transosseous holes along the peripheral glenoid face exiting the anterior glenoid neck. The sutures were secured for the labral repair states to the mounted fixture under maximal tension and released for the labral tear states and for creating the sequential bone loss models. Bone loss models were created based off a cohort of CT data on patients undergoing revision posterior labral repair surgery to develop 2 clinically relevant 3D models of glenoid bone loss: the first simulating the mean bone loss in this cohort and represented 7% or small bone loss; the second was the mean + 2SD representing 28% or large bone loss. The bone loss was created on each specimen with a 3mm round burr to match each respective 3D printed template (Figure 1). Each specimen was tested in 7 consecutive states: (1) native anatomy, (2) posterior labral tear (6-9 o’clock), (3) posterior labral repair, (4) mean posterior glenoid bone loss with labral tear, (5) mean posterior glenoid bone loss with labral repair, (6) large posterior glenoid bone loss with labral tear, and (7) large posterior glenoid bone loss with labral repair. Each state underwent 75N of posterior-inferior force and 75N of compression during the four tests at 60 and 90 degrees of flexion and 60 and 90 degrees of scaption. Posterior-inferior translation, lateral translation, and dislocation force were measured for each condition. Statistical analysis was performed using two-factor random-intercepts linear mixed-effects models. Results Compared to the labral tear state, significant increases in dislocation forces occurred with labral repair independent of bone loss state or arm position with values as follows: 14.8N (60° scaption), 12.2N (90° scaption), 11.1N (60° flexion), and 10.1N (90° flexion) with mean 12.1 ± 2.0N across all arm positions (Figure 2). Dislocation force significantly decreased between no bone loss and small bone loss (mean 12.4 ± 0.7N) and between small bone loss and large bone loss (mean 11.8 ± 2.1N) regardless of labral state in all arm positions (table 1). Posterior-inferior translation significantly decreased with labral repair compared to labral tear states independent of bone loss state in all arm positions (Table 1). Lateral translation of the humeral head significant increased when the labrum was repaired independent of bone loss state in all arm positions except 90° scaption and decreased progressively in all bone loss states in all arm positions (table 1). In the native state, the shoulder significantly translated posterior-inferior in scaption at 60° and 90° elevation compared to flexion (p<0.017) and was most unstable in 60° scaption with 29.9 ± 6.1mm posterior-inferior translation (Figure 3). Conclusions This is the first study to biomechanically evaluate posterior glenoid bone loss using a clinical model in various at-risk arm positions on a 6 degree-of-freedom robot and through a precise linear effects model has established values for the increase in dislocation force posterior labral repair provides regardless of bone loss. The most significant finding of the study is that independent of bone loss, labral repair reduced posterior dislocation forces by 12.1 ± 2.0N and significantly decreased posterior-inferior translation. With a mean decrease in dislocation force of 12.4 ± 0.7N with small (7%) bone loss, labral repair alone may be enough to restore shoulder stability in most individuals. However, significant increases in posterior bone loss may require bony augmentation for adequate stability based on individual factors such as age and activity level. [Table: see text][Figure: see text][Figure: see text]

Objectives Arthroscopic treatment with suture anchors of multidirectional instability (MDI) of the shoulder is gaining popularity as compared to an open approach, but no studies with mid to long-term outcomes are reported in the literature. Meanwhile, atraumatic onset MDI is associated with worse outcomes compared to traumatic onset MDI in short-term studies. The objective of this study is to report on survivorship and patient reported outcomes following arthroscopic pancapsular shift (APS) for MDI with minimum five-year follow up, including comparing atraumatic versus traumatic onset MDI. Methods Patients who underwent APS for MDI and were at a minimum 5 years postoperative from the surgical intervention were included. Baseline pre and perioperative data was prospectively collected as part of an institutional registry and retrospectively reviewed, and patient questionnaires were sent by email to determine long-term outcomes including mechanism of onset of MDI, patient satisfaction, Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH), American Shoulder and Elbow Surgeons (ASES), Short Form-12 Physical Component Summary (SF-12 PCS), and Single Assessment Numeric Evaluation (SANE) scores. Additional information about recurrent instability, dislocation and reoperation as well as return to sport were collected and Kaplan-Meier survivorship analysis was performed. Preoperative, short-term (1-2 year) and final follow-up patient reported outcomes were compared. Results 49 shoulders in 44 patients (15 male, 29 female) treated between October 2005 and November 2015 were included in the study. Overall, 14/49 (28.6%) of shoulders reported feelings of instability, of which 5 (10.2%) underwent revision surgery at a mean of 1.5 years postoperatively. Kaplan-Meier analysis demonstrated a survivorship rate of 80% at 5 years and 75% at 8 years with failure defined at postoperative feelings of instability. Final analysis was performed on 44 shoulders, of which minimum 5-year outcomes were collected on 36 (82%) with an average follow-up length of 9.0 years (5.1-14.6 years). All patient reported outcome scores as well as subjective improvement outcomes demonstrated statistically significantly improved results at final follow-up (p<0.05). Patient reported outcome measures were persistently statistically significantly improved at short-term and long-term final follow-up. (Figure 1) MDI onset was atraumatic in 27 shoulders and traumatic in 21. There was no difference in subjective or patient reported outcome scores between atraumatic and traumatic onset MDI patients. Rotator interval closure was performed in 19 patients with no effect on postoperative outcomes. Conclusions Arthroscopic pancapsular shift for the treatment of MDI provides excellent, durable long-term patient reported outcomes that persist from short-term follow-up. Although 28% of patients experience feelings of instability at final follow-up, most of these patients still have high postoperative satisfaction and acceptable patient reported outcomes and do not undergo revision surgery Compared to short-term data, long-term results indicate that atraumatic onset MDI is not associated with worsened postoperative outcomes as compared to traumatic onset MDI.

Objectives The purpose of this study is to report minimum 10-year survivorship and patient-reported outcomes (PROs) following primary hip arthroscopy with capsular repair for FAIS and to compare outcomes of patients undergoing capsular repair to capsular release. Methods Data were prospectively collected and retrospectively reviewed on all patients undergoing primary hip arthroscopy with capsular repair between October 2008 and February 2011. Survivorship was defined as a non-conversion to total hip arthroplasty (THA). Patients with minimum 10-year follow-up for the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and Visual Analog Scale for pain (VAS). If available, preoperative and minimum 10-year follow-up for the Hip Outcome Score—Sports Specific Subscale (HOS-SSS) were reported. Patients with ipsilateral hip surgery, worker’s compensation, Tönnis osteoarthritis grade > 1, and hip dysplasia (lateral center-edge angle < 25°) were excluded. Survivorship defined by non-conversion to THA, PROS, and clinical benefit (minimal clinically important difference (MCID) and patient acceptable symptomatic state (PASS)) were reported. An additional propensity-matched sub-analysis comparing patients undergoing capsular repair with patients undergoing capsular release over the age of 40 with acetabular labrum articular disruption ≥ 2 was performed. Results 145 (130 patients) out of 180 eligible hips (165 patients) had minimum 10-year follow-up (80.6%). 126 hips (86.9%) were female, and 19 hips (13.1%) were male. The average patient age was 30.3 ± 12.9 years. The survivorship rate was 91.0% at minimum 10-year follow-up. The cohort experienced significant improvement (P < 0.001) in the mHHS, NAHS, HOS-SSS, and VAS for pain. Additionally, the cohort achieved high rates of PASS for the mHHS (89.8%), and high rates of the MCID for the mHHS (82.4%) and VAS for pain (80.6%). 29 capsular repair hips were matched to 81 capsular release hips. Both groups experienced significant improvement in all PROs, but there was a higher conversion to THA rate in the release group (P < 0.05). Conclusions Patients undergoing primary hip arthroscopy with capsular repair experienced a high rate of survivorship of 91.0% at minimum 10-year follow-up. Patients that did not convert to THA saw favorable improvements in PROs and achieved high rates of clinical benefit. In the subanalysis, patients undergoing capsular repair demonstrated higher rates of survivorship.

Objectives There has been increased interest in sports-related concussions from the professional level down to youth leagues in recent years. Symptom types and resolution time are the metrics most often used to monitor concussions. The purpose of this study is to investigate how concussion symptoms, symptom resolution time, and use of diagnostic imaging have changed among US high school athletes from the 2007/08 through 2014/15 academic years. Methods This study analyzed concussions occurring in all sports available in the High School Reporting Information Online (RIO) database from 2007/08 through 2014/15. Chi-square tests for trend were used to calculate symptom and diagnostic imaging trends over time. Statistical significance was determined at p<0.05. Results The prevalence of each of the following symptoms was found to significantly decrease over the time period analyzed in athletes diagnosed with a concussion: amnesia (p<0.0001), confusion/disorientation (p<0.0001), dizziness/unsteadiness (p<0.01), loss of consciousness (LOC, p<0.0001), and tinnitus (p<0.0001). Among all athletes diagnosed with a concussion, the prevalence of LOC was 6.6% in 2007/08 and decreased to 2.4% in 2014/15. The prevalence of each of the following symptoms was found to significantly increase over the time period analyzed in athletes diagnosed with a concussion: drowsiness (p<0.01), irritability (p<0.0001), light sensitivity (p<0.0001), and noise sensitivity (p<0.0001). The prevalence of concentration difficulty, headaches, hyper-excitability, and nausea did not change significantly over time. The average concussion symptom resolution time has significantly increased over time (p<0.0001). The use of diagnostic plain radiographs, magnetic resonance imaging (MRI), and computed tomography (CT) scans all significantly decreased over the time period analyzed (p<0.0001 for each diagnostic test). Conclusion From the 2007/08 to 2014/15 academic years, the prevalence of various symptoms changed significantly in US high school athletes diagnosed with a concussion. The decrease in severe symptoms (LOC, amnesia, disorientation) and the increase in less recognizable symptoms (drowsiness, irritability) may point to a lower threshold used by healthcare providers in diagnosing concussions in more recent years. Improved education among healthcare providers has likely led to increased recognition of lingering symptoms in athletes diagnosed with concussions, thereby leading to a longer average symptom resolution time. Furthermore, the significant reduction in use of all forms of diagnostic head imaging demonstrates an increased recognition of concussions as functional disturbances rather than physical abnormalities detectable on imaging.

Objectives To determine predictors of clinically significant outcome achievement at a minimum of 5-year follow-up in patients undergoing hip arthroscopy for the treatment of femoroacetabular impingement syndrome with routine capsular closure. Methods Data were collected and analyzed from consecutive patients who underwent primary hip arthroscopy with routine capsular closure for the treatment of FAIS from a single fellowship-trained surgeon between January 2012 and December 2018. Baseline data, preoperative patient reported outcome measures (PROMs) and 5- year PROMs including Hip Outcome Score-Activities of Daily Living, HOS-Sports Subscale, international Hip Outcome Tool 12 questions, modified Harris Hip Score and visual analog scale pain were recorded. The minimal clinically important difference (MCID) was calculated using the distribution method while patient acceptable symptom state (PASS), and substantial clinical benefit (SCB) were determined from literature defined values. Bivariate correlations with any MCID achievement, any PASS achievement, and any SCB achievement as well as a principle components analysis for variable reduction were used to create three separate multivariate binary logistic regressions to identify significant predictors of achieving a clinically significant outcome. Results 453 patients with an average age of 34.3 ± 12.5 and average BMI of 25.5 ± 4.9 and majority female (69.1%) were included in the final analysis. There was a significant improvement in all 5-year functional outcomes when compared to preoperative scores (p<0.001 for all). At a minimum of 5-year follow-up, 82.8% of patients achieved any MCID, 69.8% achieved any PASS, and 58.9% achieved any SCB. A total of 23 patients (5.1%) of the study population underwent revision hip arthroscopy or total hip arthroplasty within the follow-up period. Female sex (Odds Ratio (OR), 2.56 [95% confidence interval (CI), 1.47 to 4.45) was a positive predictor of achieving any MCID while higher Tönnis angle (OR, 0.92 [95% CI, 0.87 to 0.98]), Tönnis grade =1 (OR, 0.34 [95% CI, 0.14 to 0.83]) were negative predictors of achieving any MCID. Higher preoperative HOS-ADL (OR, 1.03 [95% CI, 1.01 to 1.05]) and female sex (OR, 2.01 [95% CI, 1.14 to 3.55]) were positive predictors of PASS. With regards to SCB, running (OR, 2.02 [95% CI, 1.31 to 3.14]) was a positive predictor of achievement while a history of back pain (OR, 0.49 [95% CI, 0.28 to 0.86]) and preoperative chronic pain for greater than 2 years (OR, 0.62 [95% CI, 0.36 to 0.98]), were negative predictors of achievement. Conclusions At a minimum of 5-year follow-up, 82.8% of patients undergoing primary hip arthroscopy for the treatment of FAIS achieved any MCID, 69.8% achieved any PASS, 58.9% achieved any SCB. Female sex, higher preoperative PROs, and participation in running were positive predictors of achieving a clinically significant outcome while a higher Tönnis angle, Tönnis grade = 1, preoperative chronic pain, and back pain were negative predictors of achieving a clinically significant outcome.

Objectives Fractures of anterior glenoid rim, aka “Postage-Stamp” fractures, are potential complications of arthroscopic Bankart repairs that occur when a fracture line propagates through previous anchor sites producing a serrated edge. (Fig.1: A and J) Placing multiple anchors adjacent to glenoid rim in attempt to recreate the labral bumper was suggested to reduce the risk of recurrent dislocation after surgery, [Boileau et al 2006] as well as to create a stress riser that may predispose to fracture if another traumatic event may occur. This controlled laboratory study investigated the effect of increased number holes, and different types and sizes of suture anchors on the load necessary to create Postage-Stamp fractures. Our objective was to establish a safe number of anchors that could be inserted in the anterior glenoid rim without incurring in a substantially high risk of fracture. Hypothesis Increasing the number of holes and anchors and their size would decrease forces necessary to break the anterior glenoid rim. Methods We tested 46 synthetic scapulae with similar compressive strength and elastic modulus of human glenoid (4th gen. composite scapulae, Sawbones, Pacific Research Laboratories, USA) in a servohydraulic apparatus (Fig.1: B and H) following a previous published biomechanical model. [Farmer et al2014] A guide ensured holes were drilled and anchors were inserted in the same exact angle, depth and location for every specimen. (Fig.1: C to F) A metallic humeral head applied force to the anterior glenoid rim at 1mm/s until fracture occurred. (Fig. 1: G to K) Load-to-fracture of intact glenoid was compared to groups of drilling anchor holes (# 3,4,5,6 and 7) of different diameters (1.6mm and 3mm), and groups with anchors of different sizes and types (1.6mm all-suture and 3mm core anchors).(Fig.1: I to K) One-way ANOVA followed by Turkey post-hoc test compared groups to determine the number of holes necessary to weaken glenoids below 70% of intact value with a p value <0.005. Results Intact glenoid mean load-to-fracture was 1,238 ± 74N. Drilling 3 to 7 holes of 1.6mm-diameter linearly reduced load to 93%, 89%, 74%, 56% and 52% of intact value respectively, while 3.0mm drill holes reduced load to 87%, 65%, 51%, and 40% respectively.(Fig.2) Directly comparing drill role sizes there were significant differences on the 4, 5 and 7 holes groups (p=0.045, 0.032 and 0.015, respectively), so that a glenoid could safely sustain up to 5 holes of 1.6mm, but no more than 3 holes of 3.0mm-diameter.(Fig.3) Inserting 1.6mm “all-suture” anchors in the 1.6mm-diameter holes did not change the load-to-fracture on the 4 or 5 holes groups (Fig.4A), indicating that the number of drill holes was the main determinant of anterior glenoid rim strength, so that the all-suture anchors did not act as stress risers. Thus, up to 5 “all-suture” 1.6mm anchor could be safely used on a Bankart repair. The 3.0mm “core” anchors increased the load-to-fracture when compared to the group with the same number of holes of the same diameter size. Despite 4 holes of 3.0mm-diameter decreased the load-to-fracture bellow the safety line of 70% of intact value, the group with 4 anchors of 3.0mm-diameter “core” anchors increased load-to-fracture to 85% of intact value (p=0.033).(Fig.4B) This stress shield effect of the 3.0mm core anchor was not noticed on the 5 anchors group, in which the overall strength of the construction was bellow the 70% of intact safety line. Conclusions Our data call in that up to four 3.0mm “core” anchors or five 1.6mm-diameter “all-suture” anchors could be safely inserted in the anterior glenoid rim without incurring in increased risk of Postage-Stamp fracture. One should prefer small diameter anchors if more than 4 anchors were intended on a Bankart repair. This study contributed to important data about number, size and type of anchors that the anterior glenoid rim could safely sustain in order to avoid postage-stamp fracture in case a new traumatic dislocation episode occur after a Bankart repair, which is of clinical interest in high risk population preoperative planning and selection of implant size, type and number.

Objectives To evaluate whether postoperative treatment with Losartan decreased the revision rate in patients undergoing primary hip arthroscopy. Methods Patients underwent primary hip arthroscopy with labral repair and CAM osteoplasty and rim trimming between 2012 and 2017. Patients who underwent microfracture, labral debridement or reconstruction, core decompression, ligamentous teres repair or reconstruction, or capsular reconstruction were excluded. Losartan was added to all patients’ post-operative protocol in December 2015. Patients who underwent hip arthroscopy prior to November 2015 were included in the no-Losartan group (NOLOS) and patients who had arthroscopy between December 2015 and Dec 2017 were included in the losartan group (LOS). Results Of the 964 cases, follow-up was obtained on 673 patients (70%). There were 405 patients in the NOLOS group and 268 in the LOS group. There was no difference in gender distribution (P=0.128) between groups. The LOS group was significantly older (36.6 ±13 years) compared to the NOLOS group (34.1±11)(p=0.012). Average follow-up in the NOLOS group was 5.8±2 years and was 4.1±1 years in the LOS group. Revision hip arthroscopy was required in 35 (8.6%) patients in the NOLOS group and 6 (2.2%) patients in the LOS group(p=0.001). There was no difference in age between those patients who required revision (32±11 years) and those who did not(35±12 years)(p=0.137). Conclusions The prevalence of revision hip arthroscopy was significantly lower (2.2%) in patients who took Losartan as part of their post-operative protocol compared to those who did not (8.6%). Reduction in the need for revision hip arthroscopy can improve patient outcomes and reduce healthcare dollars spent.

Objectives Substantial differences in throwing metrics, like velocity, spin rate and pitcher break, have been observed between left and right-handed pitchers. Elite pitchers have demonstrated significant changes in glenohumeral range of motion and humeral torsion compared to the normal population. Differences in these anatomical parameters between left and right-handed pitchers may explain these performance trends. Furthermore, changes in shoulder range of motion measurements have been associated with different injury risks and challenges in assessing rehabilitation progress. This study seeks to determine if differences in glenohumeral range of motion and humeral torsion exist between left-handed and right-handed pitchers. Methods 217 MLB pitchers from a single organization were evaluated over a 7-year period from 2013-2020. Range of motion was evaluated by three trained examiners using a Standard Goniometer. Ultrasound scanning was used to determine neutral position of the shoulder and the degree of humeral torsion was measured with a goniometer. The mean and standard deviation were assessed for normality using Shapiro Wilk. Differences between right and left-handed pitchers were assessed using one-way ANOVA. Arm effects were assessed using paired samples t-tests. Results Right-handed pitchers showed, on average, 13.9 degrees more shoulder external rotation range in their dominant arm compared with their non-dominant arm, whereas left-handers averaged only 2.2 degrees. RHPs showed greater asymmetries in shoulder internal rotation range (13.9 vs 4.8 degrees) and humeral torsion (-23.1 vs -2.2 degrees). Left-handed pitchers showing significantly greater range of non-dominant shoulder flexion (165.8 vs 160.7 degrees) leading to greater flexion deficits in the dominant arm compared to their right-handed counterparts, (7.5 vs 0.0 degrees). Conclusions Right-handed pitchers demonstrate significantly greater measures of external rotation, humeral retrotorsion, and shoulder flexion compared to left-handed counterparts. The correlation between humeral retrotorsion and increased external rotation indicate that osseus adaptations are a major contributor to range of motion differences associated with handedness. Additionally, these findings may explain observed differences in several throwing metrics between right and left-handed pitchers. Furthermore, knowledge of these differences can inform rehabilitations programs and shoulder maintenance regimens. [Table: see text][Table: see text][Figure: see text][Figure: see text]

Objectives Non-healing of rotator cuff tears is estimated to be between 5 and 20%. Rehabilitation protocols vary. Some advocate early rehabilitation. The aim of the study was to verify whether rapid recovery of mobility was not associated with a higher rate of non-healing. Methods We conducted a single-center prospective study. The primary inclusion criterion was first-line arthroscopic repair of an isolated complete cuff tear without retraction (Patte 1) or fatty degeneration (Goutallier - less than 2). It was the same surgeon, the same surgical technique (double row) and the same rehabilitation protocol (self-mobilization, hands together). Patients were seen again by an evaluator other than the surgeon. We analyzed passive elevation and external rotation (ER1) mobility and pain at 6 weeks, 3 months, and 6 months, active mobilities at 3 months and 6 months, and the Constant score at 6 months. Tendon healing was assessed at six months by ultrasound according to Sugaya’s classification (grouping 1/2/3 healed and 4/5 unhealed). Results 1,200 patients were included, 101 were excluded (lost to follow-up or missing data at one of the reviews). The healing rate was 85.7%. We noted a statistically significant difference between the healed and unhealed groups for passive elevation at 6 weeks (128° vs 142° p <0.0001), passive ER1 (23°/32°, p <0.0001). As well as at 3 months for passive elevation (149°/155°, p = 0.0005) for ER1 (43°/48°, p = 0.0008). No difference in pain between the 2 groups (at each review) nor in the final Constant score (72.3 vs 70.2) Conclusion Patients with poorer passive joint mobility at 6 weeks and 3 months postoperatively had a better healing rate at 6 months. This clear correlation is an indication that we should reflect on the earliness of rehabilitation after rotator cuff repair.

Objectives Although much as been done to better understand and characterize the epidemic of UCL reconstruction in pitchers, a comprehensive review of all UCL reconstructions performed in professional baseball pitchers is surprisingly lacking. Accordingly, the purpose of this work was to provide an epidemiologic report on every UCL reconstruction ever performed in professional baseball with a special focus on outcomes (return to play rates and time) and overall survivorship. Methods Three resources (including the Major League Baseball [MLB] injury tracking system) were combined and cross-referenced to identify all professional baseball players who had ever undergone primary UCL reconstruction (1974 to 2015). Variables analyzed included the date of injury, date of surgery, time out of play, geographical region, and revision status. Trends over time were analyzed collectively and based on level of play at the time of surgery. A minimum of 2 years of follow up was required to determine return to play status. Revision free Kaplan-Meier survivor analysis was performed. Results A total of 1,313 UCL reconstructions were identified. The annual rate of primary and revision UCL reconstructions rose significantly for all levels of play from 1974 to 2015 and from (p<0.001). The overall mean time to return to play (RTP) was 436 days (range 98 to 1,643). The rate of RTP to any level was 93.9% for MLB pitchers vs. 76.3% for MiLB pitchers (p<0.001), and MLB pitchers RTP at the MLB level in 73.1% of cases. The time to RTP was longer (by 54 days) for revisions (p=0.025) compared to primaries, and MLB pitchers RTP from primary surgery 95.6% of the time but only 81.8% for revision surgery (p=0.008). The revision rate was 10.7%, and the percentage of players free of revision and still playing professional baseball was 92% at 2 years, 53% at 5 years, and 17% at 10 years. Survivorship was improved for players undergoing UCL reconstruction before age 25 opposed to after 25. Conclusion This study represents the most robust epidemiologic report of UCL reconstruction in baseball to date, and a number of novel findings are reported. A number of key differences in MLB and MiLB, as well as primary and revision surgeries, were identified. Although the revision rate (10.7%) is higher than prior reports, 75% of players who had surgery before age of 25 are revision free and still playing professional baseball four years post operative.

Objectives Despite the value to future coaches, franchise management, and medical personnel, little is known about the epidemiology of musculoskeletal injuries and surgeries and their future impact prior to the MLB draft. The purpose of this study was to determine the (1) epidemiology of all musculoskeletal injuries and surgeries for predraft MLB players; (2) risk of injury or surgery on draft position; (3) risk of injury or surgery on availability within the first two years; and (4) risk of injury or surgery on performance. Methods A total of 1,890 medical records conducted by MLB team physicians prior to the draft were retrospectively reviewed from 2014 to 2018. Players were divided into three groups: non-injured (no musculoskeletal history), non-operative (previously injured but treated non-operatively), and operative (previous injury requiring surgery). Game statistics, including draft round, missed games, batting average (BA), and earned run average (ERA) for the first 2 seasons of MLB play were obtained for all available players, Players were matched for position, and confounders were analyzed for age, draft round using ANOVA analysis. Results A total of 927 pitchers and 963 position players were evaluated, and 38.9% had no reported injury history, 48.6% reported injury but were treated non-operatively, and 12.4% were treated operatively. The most common pre-draft injuries were elbow tendonitis (n=312), UCL injury (n=212), and shoulder labral tear (n=76). The most common pre-draft treatments were physical therapy (922, 25.3%), UCL reconstruction (115, 3.2%), and fracture fixation (69, 1.9%). No difference was found between non-injured, non-operative, and operative groups in terms of draft position, games missed, and performance (BA for position players, p = 0.7246; ERA for pitchers, p=0.1956). After position matching, age and draft round were non-confounding. Conclusion More than half of players entering the MLB report a musculoskeletal injury requiring treatment, with the most common pathology involves the shoulder and elbow. After position matching and analyzing for confounding factors like age and draft round, musculoskeletal history did not macroscopically impact draft position, short-term availability, or performance.

Objectives With the accumulation of big data surrounding National Hockey League (NHL) and the advent of advanced computational processors, machine learning (ML) is ideally suited to develop a predictive algorithm capable of imbibing historical data to accurately project a future player’s availability to play based on prior injury and performance. To the end of leveraging available analytics to permit data-driven injury prevention strategies and informed decisions for NHL franchises beyond static logistic regression (LR) analysis, the objective of this study of NHL players was to (1) characterize the epidemiology of publicly reported NHL injuries from 2007-17, (2) determine the validity of a machine learning model in predicting next season injury risk for both goalies and non-goalies, and (3) compare the performance of modern ML algorithms versus LR analyses. Methods Hockey player data was compiled for the years 2007 to 2017 from two publicly reported databases in the absence of an official NHL-approved database. Attributes acquired from each NHL player from each professional year included: age, 85 player metrics, and injury history. A total of 5 ML algorithms were created for both non-goalie and goalie data; Random Forest, K-Nearest Neighbors, Naive Bayes, XGBoost, and Top 3 Ensemble. Logistic regression was also performed for both non-goalie and goalie data. Area under the receiver operating characteristics curve (AUC) primarily determined validation. Results Player data was generated from 2,109 non-goalies and 213 goalies with an average follow-up of 4.5 years. The results are shown below in Table 1.For models predicting following season injury risk for non-goalies, XGBoost performed the best with an AUC of 0.948, compared to an AUC of 0.937 for logistic regression. For models predicting following season injury risk for goalies, XGBoost had the highest AUC with 0.956, compared to an AUC of 0.947 for LR. Conclusion Advanced ML models such as XGBoost outperformed LR and demonstrated good to excellent capability of predicting whether a publicly reportable injury is likely to occur the next season. As more player-specific data become available, algorithm refinement may be possible to strengthen predictive insights and allow ML to offer quantitative risk management for franchises, present opportunity for targeted preventative intervention by medical personnel, and replace regression analysis as the new gold standard for predictive modeling. [Figure: see text]

Objectives Meniscus tears in a young population often occur from a traumatic, rotational mechanism of injury, which is similar to that of an ACL tear. However, there is limited evidence regarding the risk of subsequent ACL injury following a surgically treated isolated meniscus tears. The purpose of this study was to investigate the risk of subsequent ipsilateral ACL reconstruction (ACL-R) in patients who were surgically treated for isolated meniscus tears compared to the incidence of ACL-R in the general population. We hypothesized that a prior meniscus tear, more specifically a bucket-handle tear, is indicative of a more severe injury and thus increases the risk of subsequent ipsilateral ACL-R. Methods The PearlDiver Mariner 91 database was queried for patients aged 10-40 years who were surgically treated for isolated meniscus tears using CPT and ICD-10 codes between 2015 to 2020. Patients with any prior cruciate or ligamentous or meniscus injury of the knee or surgery, other concurrent arthroscopic procedure of the knee apart from meniscus repair or meniscectomy, and any concurrent fractures of the femur, tibia, fibula, or patella were excluded. The population incidence for first time ACL-R was determined in patients with same 10-40 year age range and during the same 2015-2020 time period. Cohorts for meniscal tear pathology (including laterality) and surgical treatment (repair vs. meniscectomy) were formed. Ipsilateral subsequent re-operations for ACL-R were tracked up to 5 years. Multivariate logistic regression was performed to compare the risk of subsequent ipsilateral ACL-R after isolated meniscus tear treated surgically to the general population incidence of ACL-R. Results In total, 106,185 isolated meniscus tears that underwent repair or meniscectomy were identified (Figure 1). The population incidence for first time ACL-R was ≈ 0.2%. After controlling for demographics, comorbidities, and procedure type, patients that were surgically treated for an isolated BH tear (1.7%) were at significantly higher odds of ACL-R within 5 years compared to population incidence of ACL-R (OR 8.54, P<0.001) (Table 1). Medial BH tears (2.2%) had significantly increased odds of ACL-R up to 5 years (OR 10.87, P < 0.001). Non-BH tears (0.9%) had significant higher odds of ACL-R up to 5 years (OR 3.66, P<0.001). Medial BH tears that were repaired (4.0%) had the highest odds of ACL-R (17.53, P<0.001) up to 5 years relative to the general population. Conclusions The present study is the first to analyze the odds of ACL-R after suffering a prior meniscus tear treated surgically. We found that patients with surgically treated, isolated BH tears are significantly more likely to require ipsilateral ACL-R surgery compared to those treated for all other types of isolated meniscus injuries. Medial BH tears conferred the greatest odds of requiring subsequent ACL-R, suggesting that a BH meniscus tear, especially a medial sided BH tear, is a possible sign of underlying knee instability. Such findings suggest that for patients who undergo surgical treatment for isolated BH tears, ACL injury prevention should be incorporated into rehabilitation protocols. [Figure: see text][Table: see text]

Aims and Objectives Post-operative infection of the knee is one of the major concerns following ACL-reconstruction. The purpose of this study was to investigate whether the pre-soaking of hamstring grafts in vancomycin reduces the incidence of post-operative infection. Materials and Methods This prospective study included more than 1000 patients undergoing primary ACL-reconstruction over a period of 4 years. Group 1 received intra-operative iv-antibiotics without pre-soaking of the graft. Group 2 received iv-antibiotics and additionally the graft was bathed in a vancomycin solution of 5 mg/mL. Results In group 1, a total of 2,3% of the patients suffered a post-operative joint infection. In contrast, there were no post-operative infections in the second group (0%). Statistical analysis revealed a significantly reduced post-operative infection rate when bathing the autograft in vancomycin. Conclusion Pre-soaking of hamstrings grafts with vancomycin combined with classical iv antibiotic prophylaxis reduced the rate of post-operative infection when compared to iv-antibiotics alone. This technique should be utilized to reduce the overall incidence of knee infections following ACL reconstruction.

Objectives: Many long-term outcome studies have looked at risk factors for developing osteoarthritis after anterior cruciate ligament reconstruction (ACL). The purpose of this study was to evaluate the effect of post-operative graft laxity as measured by KT-1000 arthrometry on long-term clinical knee scores as well as the subsequent risk of additional knee surgery in transtibial ACL reconstructed patients. Methods: Between 1992 and 1998, a cohort study of 171 consecutive patients undergoing transtibial bone-patellar tendon-bone ACL reconstruction was performed. Any patient with a history of prior ipsilateral or contralateral ACL reconstruction, menisectomy or cartilage restoration was excluded from this study. At 6, 12 and 24 months postoperatively, patients were evaluated by clinical examination, subjective and objective scoring systems, and KT-1000 arthrometry. Patients with a side to side difference of less than 3mm as measured by KT-1000 were considered ‘tight grafts’ and patients with a side to side difference of greater than 5mm were considered ‘loose’. At long-term follow-up patients completed subjective outcomes scores as well as questionnaires regarding their knee function. Differences within and between groups were analyzed. Results: The study cohort comprised of eighty-five patients who met inclusion criteria; sixty-five ‘tight’ patients, and twenty ‘loose’ patients. 46 of 65 ‘tight’ patients (71%) and 15 of 20 ‘loose’ patients (75%) were available at long-term follow up (average 17 years; range 14.25 to 19.2). Lysholm scores improved significantly from pre-operative levels in both ‘tight’ and ‘loose’ reconstructions at both 2-year and long-term follow up; ‘tight’ grafts improved from 65.8 ± 20.0 to 93.8 ± 7.7, p<0.0001 and 90.4 ± 10.4, p<0.0001 at 2-year and long-term follow up respectively, whereas ‘loose’ grafts improved from 74.2 + 13.4 to 94.4 ± 6.7, p=0.0003 and 90.0 ± 13.5, p=0.01 respectively. In addition, Lysholm scores at 17-years did not differ significantly from 2-year post-operative scores in either group (‘tight’, p=0.10; ‘loose’, p=0.18). Moreover, at long-term follow-up, there was no significant difference between ‘tight’ or ‘loose’ reconstructions in any outcome measure; Lysholm p=0.85, Tegner p=0.77, KOOS p=0.96, and IKDC (subjective) p=0.42. Tegner activity scores did, however, deteriorate significantly within each group at 17-years when compared with 2-years’ scores (‘tight’, p=0.003; ‘loose’, p<0.01). With respect to number of additional surgical procedures required on the ACL reconstructed knee at 17 years, there was no difference between groups (24% ‘tight’, 7% loose; p=0.15). Conclusion: A side to side difference of greater than 5mm as measured by KT-1000 arthrometry has historically been considered a failure of ACL reconstruction. Our study suggests that a clinically loose post-operative result may not correlate with clinical failure at 17-year follow-up, and that transtibial ACL reconstruction still can provide excellent clinical results at long-term follow up.

Background Arthroscopic rotator cuff repair is a common but technically difficult surgical technique. This study describes a novel arthroscopic rotator cuff repair technique where the repair was performed while visualized entirely from the glenohumeral joint. A single-row knotless tension band inverted mattress suture technique was utilized with fixation obtained via suture anchors. The technique was relatively easy to perform and demonstrated good repair strength and footprint compression in an ex vivo ovine model. Purpose To evaluate the safety and efficacy of this technique in 1000 consecutive patients. Study Design Case series; Level of evidence, 4. Methods This study was a retrospective analysis of prospectively collected data in 1000 consecutive patients. Included patients underwent primary arthroscopic rotator cuff repair by a single surgeon performing the undersurface repair technique and attended 6-month follow-up with ultrasound evaluation to determine repair integrity. Exclusion criteria were irreparable tears, incomplete repairs, tendon reconstruction with a synthetic patch, and revision cases. Results The only complication was retear. The overall retear rate at 6 months following repair with the undersurface technique was 8.5%. The mean ± SEM operative time for the technique was 16 ± 0.3 minutes (range, 4-75 minutes). There were no infections. Smaller tears were repaired faster and had better healing rates. Conclusion The novel all-inside arthroscopic rotator cuff repair technique was safe and significantly faster and provided better healing rates than other repair techniques. The retear rate of 8.5% is, to the authors’ knowledge, the lowest reported rotator cuff retear rate in a large cohort of patients based on a single technique.

Objectives Today’s new generations of artificial turf infill systems are increasingly being installed with lighter weight infill systems, which often incorporate interlocking polypropylene or thermoelastomer pad systems under the fiber-infill layers, reportedly to reduce surface shock, decrease concussions, and enhance shoe: surface stability. At this time, however, the effects of pad systems on high school football trauma during game conditions are unknown. With more than one million athletes playing competitive football, the rise in medical costs, and the increasing popularity of base pads being installed today as an alternative to heavier infill weight systems, this study focused on quantifying the potential influence of this practice on the incidence, mechanisms, and severity of game-related, high school varsity football injuries. Methods Artificial turf playing fields were divided into two groups based on a pad underlayer or a no pad system. Fifty-eight high schools participated across three states over 7 seasons. Outcomes of interest included injury severity, injury category, primary type of injury, injury mechanism, anatomical location of trauma, type of tissue injured, and elective imaging/surgical procedures. Data were subject to multivariate analyses of variance (MANOVA) and Wilks’ λ criteria using general linear model procedures. Data were expressed as injury incidence rates (IIR) per 10 game season. Results Of 658 varsity games documented, 260 games were played on fields containing pads, and 398 on no-pad fields, with 795 total injuries reported. MANOVA indicated a significant main effect across pad and no pad playing surfaces by injury severity (F 3,791 = 11.436; P < .0001), knee trauma (F 9,785 = 2.435; P = .045), injury category (F 3,791 = 3.073; P < .0001), primary type of injury (F 10,785 = 2.660; P < .0001), injury mechanism (F 13,781 = 2.053; P < .001), anatomical location of trauma (F 16,778 = 1.592; P < .001), type of tissue injured (F 4,790 = 4.485; P < .0001), and elective imaging and surgical procedures (F 4,790 = 4.248; P < .002). Post hoc analyses indicated significantly higher ( P < .05) substantial injury [10.3, (95% CI, 10.0-10.5) vs 3.0 (2.5-3.4)], player-to turf trauma [6.5, (95% CI, 5.9-7.1) vs 2.0 (1.6-2.4)], patellofemoral syndrome [1.3, (95% CI, 0.9-1.7) vs 0.3 (0.2-0.5)], neck strain [2.0, (95% CI, 1.5-2.5) vs 0.3 (0.2-0.5)], lower leg strain [3.9, (95% CI, 3.3-4.5) vs 1.1 (0.8-1.4)], and a higher number of lower extremity elective imaging and surgical procedures requested [7.2, (95% CI, 6.7-7.7) vs 3.2 (2.8-3.7)] when competing on artificial turf fields with pads as compared to no pad systems, respectively. In regard to reducing the frequency of concussions, there was no significant difference in concussion rate attributed to turf impact [0.3, (95% CI, 0.2-0.6) vs 0.1 (0.1-0.3)] between pad and no pad fields, respectively. Conclusions The addition of a pad under an artificial turf surface increases injury rates when compared to non-pad fields across most injury categories. At this time, findings do not support the current trend of installing lightweight padded infill systems at the high school level of play. This is the first longitudinal study to investigate the influence of a pad on sport trauma, when integrated with an artificial turf infill system.

Objectives: SLAP tears and tendonitis disorders of the long head of the biceps tendon (LHBT) remain a challenge to treat in an active population. The purpose of this study is to prospectively compare the surgical outcomes of a primary biceps tenodesis for SLAP tears and biceps tenosynovitis in a young active population. Methods: Over a 6-year period, 125 patients with mean age of 42.6 (range, 26.3 to 56.5) with a diagnosis of LHBT were prospectively evaluated. Inclusion criteria included patients with a clinical diagnosis of a type II SLAP or anterior shoulder pain who failed conservative management and underwent a diagnostic shoulder arthroscopy. Patients were excluded for full-thickness rotator cuff tears, AC joint pathology, and labral pathology outside of the SLAP lesion. Patients with an arthroscopically confirmed labral tear or biceps tendonopathy underwent a mini-open subpectoral tenodesis with interference screw and were independently evaluated with patient reported outcome measurements (SANE, WORC), and a biceps position examination. Statistical analysis was via Student’s t-test and significance set at p <.05. Results: 101 of 125 patients (81%) completed the study requirements at a mean of 2.75 years (range 1.5 to 5.7 years). 50 Patients were diagnosed with SLAP II tears (40%) and 75 patients with biceps tendonitis (60%), 28 (22%) underwent a rotator cuff debridement for a concomitant low-grade partial rotator cuff tear and LHBT instability. There was a clinically and statistical improvement in patient outcomes scores: (WORC=54%, SANE=58) improved to (WORC=89%, SANE=89.5, p<0.01). 82% of patients returned to work and full activity at a mean of 4.1 months. The biceps muscle measured relative to the antecubital fossa of operative (mean 3.20 cm) versus non-operative (3.11 cm) was not clinically different (p=0.57), except in the 3 that failed tenodesis fixation. There was an 8% complication rate: 3 patients sustained failure of the LHBT tenodesis requiring revision; 2 superficial infections treated with antibiotics; and 3 transient musculoskeletal neruopraxias. Conclusion: A primary biceps tenodesis for pathology of the LHBT provides a clinical and statistically significant improvement in shoulder outcomes with a reliable and efficient return to previous activity level and low risk for surgical complications. However, additional work is necessary to define optimal primary treatment of LHB disorders.

Objectives Chondrogenic mesenchymal cells have been developed from human pluripotent stem cells (hPSCs) as a human model of embryonic chondrogenesis. These cells are expandable in the presence of fibroblast growth factor (FGF), and the types of cartilage they tend to generate have been characterized in vitro and in vivo. Resistance to endochondral ossification is one of the most important characteristics of the tissue engineered cartilage for cartilage regenerative therapy. Despite some reports on directed derivation of endochondral ossification resistant chondrocytes from hPSCs, their precursors (chondrogenic mesenchymal cells) have been poorly characterized. We have developed methods to generate two types of chondrogenic mesenchymal cells that lead to cartilage pellets expressing high or very low levels of hypertrophic chondrocyte markers in vitro. These cartilage pellets, when transplanted, became either fully mineralized bony tissue or remained unmineralized, respectively. Here, we present results from cell-type analyses of the two types of mesenchymal cells using the genome-wide RNA-seq technology, aiming to provide mechanistical insights into how the two types of mesenchymal cells prefer to form different types of cartilage. Methods Human PSC lines were differentiated toward paraxial mesodermal progeny in a chemically-defined medium (CDM) as previously described (1, 2), and mesodermal cells were isolated by cell sorting (2, 3). The isolated cells were then cultured in CDM containing FGF2, platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta) inhibitor and glycogen synthase kinase (GSK) inhibitor (1), which were then subjected to CDM containing FGF2, TGFbeta inhibitor and GSK inhibitor (FSbC medium) as well as to CDM containing PDGF and BMP inhibitor (PN medium) to generate mesenchymal cells of distinct size and shape. The resulting cells were subjected to RT-PCR and bulk RNA-seq analyses for cell-type determination. Chondrogenesis was done by pellet culture using PDGF, TGF-beta3 and bone morphogenetic proteins, as described previously (1, 2). Some cartilage pellets were fixed, sectioned, and stained with Toluidine Blue and von Kossa, or immunostained with anti-collagen type I, II and X (COL1, 2, 10) antibodies. DNA, RNA, and sulfated glycosaminoglycan were isolated and quantified from unfixed cartilage pellets. Some cartilage pellets were also subcutaneously transplanted into NSG (severely immunocompromised) mice and the recovered cartilage pellets were similarly analyzed. All the methods involved were previously described in detail (1, 2). Results The PN cultured mesenchymal cells (Fig. 1) developed COL2 ⁺ cartilage pellets that expressed COL10A1 at 10 to 100-fold lesser levels and PRG4 (Lubricin gene) at higher levels than those derived from the FSbC cultured mesenchymal cells, and were resistant to endochondral ossification after subcutaneous transplantation for 8 weeks (Fig. 2) (1, 2). In contrast, the FSbC cultured mesenchymal cells (Fig. 1) developed cartilage pellets that expressed COL10A1 at higher levels than those derived from the PN cultured mesenchymal cells, and were readily mineralized after subcutaneous transplantation (Fig. 2) (1, 2). The comparative RNA-seq analyses of the two mesenchymal cell populations showed that the FSbC cells resembled ectomesenchymal cells derived from neural crest progeny of hPSCs (1, 2) and the PN cells consisted of cells resembling mesenchymal stromal cells and ligament/tendon progenitors (Fig. 3). Conclusions From hPSCs, chondrogenic mesenchymal cells of distinct chondrogenesis activity can be generated in vitro in a controlled fashion. One type leads to chondrocytes prone to endochondral ossification, and the other type leads to rather stable cartilage that seems to resist endochondral ossification. Our results suggest that the fate of hPSC-derived chondrocytes can be controlled at the mesenchymal cell (i.e., chondrocyte precursor)-stage, which seems to be dependent on how the mesenchymal cells are generated from hPSCs and maintained in culture. Further biological studies on these cells will not only enable hPSC-derived chondrocytes/chondroprogenitors to be used directly for cartilage regenerative therapy, but also may lead to a critical mechanism that allows therapeutically relevant adult chondrogenic cells such as skeletal stem cells to reproducibly regenerate hyaline permanent cartilage during cartilage repair. [Figure: see text][Figure: see text][Figure: see text]

Objectives Tranexamic acid (TXA) is widely used in arthroplasty procedures and has recently gained popularity as an adjunct for improving perioperative outcomes after arthroscopic procedures. However, the safety, side-effect profile, and efficacy of various routes of administration (intravenous and intraarticular) of tranexamic acid in arthroscopic surgery have not been clearly delineated. The objectives of this study are to analyze the available literature on overall safety, efficacy, and complications such as deep vein thrombosis, pulmonary embolus, and infection following administration of intravenous (IV) or intraarticular (IA) tranexamic acid in arthroscopic procedures. Methods A literature search in agreement with the Preferred Reporting Items from Systematic Reviews and Meta-Analyses (PRISMA) protocol was performed to retrieve randomized controlled trials examining the use of tranexamic acid at the time of arthroscopic procedures. Inclusion criteria included randomized controlled trials (RCT), published at any time, which report adverse clinical outcomes, including deep vein thrombosis, pulmonary embolus, and adverse reactions following arthroscopic procedures, in which patients were randomized into an experimental group who received TXA (either intravenously or via intra-articular injection) preoperatively and a control group who did not receive TXA. The exclusion criteria were those studies that were non-RCT and did not assess outcomes following arthroscopic procedures. The studied outcomes included: thromboembolic events, adverse drug reactions, postoperative drain output, VAS pain scores, and joint aspiration requirements. Results Thirteen prospective randomized controlled trials met inclusion criteria for analysis and were included in this review. These studies examined a total of 1,159 arthroscopic procedures, comprised of 174 hip arthroscopy procedures, 810 knee arthroscopy procedures for ACL reconstruction, 103 knee arthroscopy procedures for meniscectomy or repair, and 72 shoulder arthroscopy procedures for rotator cuff repair. Tranexamic acid use in arthroscopic procedures resulted in no increase in thromboembolic events or adverse drug reactions, with no thromboembolic events or adverse drug reactions reported across the 1,159 procedures. Tranexamic acid in IV and IA forms used in ACL reconstruction reduced 24-hour postoperative drain output (-48.47cc; P=0.001 in IV TXA and -39.11cc, P=0.004 in IA TXA group when compared to control) and improved VAS pain scores in the early postoperative period at 1 week (-1.4, P<0.00001 in IV TXA and -1.68, P<0.00001 in IA TXA when compared to control) as demonstrated in Figure 1a and 1b. Further, IV TXA resulted in a significant reduction in postoperative aspiration requirement compared to control (Odds Ratio 0.37, P=0.02) following ACL reconstruction as demonstrated in Figure 2. Conclusions The use of IV or IA TXA in arthroscopic surgery including rotator cuff repair, meniscus, femoroacetabular impingement surgery, and ACL reconstruction is safe and confers no increased risk of thromboembolic events. IV and IA TXA have proven to be effective in reducing postoperative drain output and even reducing pain in the early postoperative period following ACL reconstruction. Finally, IV TXA has been shown to reduce the need for postoperative aspiration following ACL reconstruction.