Arlen D Hanssen

Mayo Clinic - Rochester, Рочестер, Minnesota, United States

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Publications (239)798.31 Total impact

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    ABSTRACT: Total knee arthroplasty (TKA) is highly successful, with an exponential increase expected in the near future [1, 2]. More importantly, a fivefold increase in the number of revision TKAs is expected by 2030 [1, 2]. In the latest studies, the top seven reasons for revision TKA include aseptic loosening (23.1 %), infection (18.4 %), polyethylene wear (18.1 %), instability (17.7 %), pain/stiffness (9.3 %), osteolysis (4.5 %), and malposition/misalignment (2.9 %) [1, 3]. With modern implants, constraint can be effectively managed [4]. However, one of the remaining challenges in revision TKA is the management of severe bone loss [4]. Traditionally, allografts have been widely utilized to manage bone loss, with a significant failure rate at only mid-term follow-up [4]. New techniques with restoration of the metaphysis have been developed to optimize the results of revision TKA [4-8]. In this editorial, it was our aim to present contemporary management solutions for severe bone loss encounter ...
    European Journal of Orthopaedic Surgery & Traumatology 03/2015; 25(4). DOI:10.1007/s00590-015-1615-4 · 0.18 Impact Factor
  • Atul F Kamath, David G Lewallen, Arlen D Hanssen
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    ABSTRACT: Severe metaphyseal and meta-diaphyseal bone loss poses important challenges in revision total knee arthroplasty. The best strategy for addressing massive tibial bone loss has not been determined. The purpose of this study was to assess the intermediate-term clinical and radiographic results of porous tibial cone implantation. Sixty-six porous tantalum tibial cones (sixty-three patients) were reviewed at a mean follow-up time of seventy months (range, sixty to 106 months). According to the Anderson Orthopaedic Research Institute bone defect classification, twenty-four knees had a Type-3 defect, twenty-five knees had a Type-2B defect, and seventeen knees had a Type-2A defect. The mean age at the time of the index revision was sixty-seven years (range, forty-one to eighty-three years), and 57% of patients were female. The mean American Society of Anesthesiologists Physical Status was 2.4 (range, 2 to 3), and the mean body mass index was 33 kg/m(2) (range, 25 to 53 kg/m(2)). Fifteen patients (24%) were on immunosuppressant medications, and eight patients (13%) were current smokers. The patients underwent a mean number of 3.4 prior knee surgical procedures (range, one to twenty procedures), and 49% of patients (thirty-one patients) had a history of periprosthetic infection. The mean Knee Society Scores improved significantly from 55 points preoperatively (range, 4 to 97 points) to 80 points (range, 28 to 100 points) at the time of the latest follow-up (p < 0.0001). One patient had progressive radiolucencies about the tibial stem and cone on radiographs. One patient had complete radiolucencies about the tibial cone, concerning for fibrous ingrowth. Three other cones were revised: one for infection, one for aseptic loosening, and one for periprosthetic fracture. Revision-free survival of the tibial cone component was >95% at the time of the latest follow-up. Porous tantalum tibial cones offer a promising management option for severe tibial bone loss. At the intermediate-term follow-up (five to nine years), porous tantalum tibial cones had durable clinical results and radiographic fixation. The biologic ingrowth of these implants offers the potential for successful long-term structural support in complex knee reconstruction. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.
    The Journal of Bone and Joint Surgery 02/2015; 97(3):216-223. DOI:10.2106/JBJS.N.00540 · 4.31 Impact Factor
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    ABSTRACT: Porous tantalum monoblock cups have been proposed to improve survivorship of cementless primary THA. However, there are few direct comparative trials to established implants such as porous-coated titanium cups. 113 patients were randomized into two groups according to the cup: a porous tantalum monoblock cup (TM) or a porous-coated titanium monoblock cup (control). At a mean of 12 years after THA, no implants migrated in both groups. Two TM patients (4%) and 13 control patients (33%) presented with radiolucency around the cup (P<0.001). In the control group, 1 cup (2%) was revised for aseptic loosening. At 12 years post-implantation, porous tantalum monoblock cups demonstrated 100% survivorship, and significantly less radiolucency as compared to porous-coated titanium monoblock cups. Copyright © 2015 Elsevier Inc. All rights reserved.
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    ABSTRACT: Postoperative periprosthetic femur fractures are an increasing concern after primary total hip arthroplasty (THA). Identifying and understanding predisposing factors are important to mitigating future risk. Femoral stem design may be one such factor. The goals of our study were to compare the (1) frequency of periprosthetic femur fracture and implant survivorship; (2) time to fracture in those patients who experienced periprosthetic femur fracture; and (3) predictive risk factors for periprosthetic femur fracture between a unique stem design with an exaggerated proximal taper angle and other contemporary cementless, proximally fixed, tapered stems. We reviewed all hips in which a femoral hip component with a uniquely exaggerated proximal taper angle (ProxiLock) was implanted during primary THA at a single academic institution. That group of patients was compared with a cohort of patients who underwent primary THA during the same time interval (1995-2008) in which any other cementless, proximally fixed, tapered stem design was used. The two groups differed somewhat in terms of sex, age, and body mass index, although these differences were of unclear clinical significance. During the study, 3964 primary THAs were performed using six different designs of cementless, proximally fixed, tapered femoral hip prostheses. There were 736 stems in the ProxiLock (PL) patient group and 3228 stems in the non-ProxiLock (non-PL) group. In general, the stem highlighted in this study became the routine cementless stem used for primary THA for three arthroplasty surgeons without specific patient or radiographic indications. Periprosthetic fractures were identified within each group. The incidence, timing, type, and treatment required for each fracture were analyzed. The Kaplan-Meier method was used to determine study patient survival free of any postoperative fracture. Radiographs and the electronic medical record of each patient who sustained a fracture were reviewed. Followup was comparable between groups at all time points. The Kaplan-Meier estimate for fracture-free patient survival was worse in the PL group at all time points with survival of 98.4% (range, 97.4%-99.3%), 97.1% (range, 95.9%-98.3%), 95.4% (range, 93.8%-97.0%), and 92.6% (range, 89.6%-95.3%) at 30 days, 1 year, 5 years, and 10 years, respectively, for the PL patient group compared with 99.8% (range, 99.7%-99.9%), 99.6% (range, 99.3%-99.8%), 99.3% (range, 99.0%-99.6%), and 98.4% (range, 97.5%-99.1%) in the non-PL patient group (p < 0.001). Patients in the PL group had increased cumulative probability of both early and late fractures with cumulative probabilities of fracture of 2.5% (range, 1.3%-3.6%) at 90 days and 7.4% (range, 4.7%-10.4%) at 10 years compared with probabilities of 0.3% (range, 0.1%-0.5%) at 90 days and 1.6% (range, 0.8%-2.5%) at 10 years in the non-PL group (p < 0.001). Patients in the PL group had an increased risk of postoperative periprosthetic femur fracture (hazard ratio [HR], 5.6; 95% confidence interval [CI], 3.4-9.1; p < 0.001); fracture requiring reoperation (HR, 8.4; 95% CI, 4.4-15.9); p < 0.001); and fracture requiring stem revision (HR, 9.1; 95% CI, 4.5-18.5; p < 0.001). Age older than 60 years was also a risk factor for fracture (HR, 3.7; 95% CI, 2.1-6.4), but sex, body mass index, and preoperative diagnosis were not predictive. Hips implanted with an uncemented femoral stem, which has a uniquely exaggerated proximal taper angle, had an increased risk of both early and late postoperative periprosthetic femur fracture. The majority of patients with a fracture underwent reoperation or stem revision. The unique proximal geometry, lack of axial support from the smooth cylindrical distal stem as well as resorption of the hydroxyapatite coating and poor ongrowth with subsequent subsidence may contribute to increased risk of fracture. Although this particular stem has recently been discontinued by the manufacturer, these findings are important in regard to followup care for patients with this stem implanted as well as for future cementless stem design in general. Level III, therapeutic study.
    Clinical Orthopaedics and Related Research 12/2014; DOI:10.1007/s11999-014-4077-9 · 2.88 Impact Factor
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    ABSTRACT: There is increasing interest in using administrative claims data for surveillance of surgical site infections in THAs and TKAs, but the performance of claims-based models for case-mix adjustment has not been well studied. Performance of claims-based models can be improved with the addition of clinical risk factors for surgical site infections. We assessed (1) discrimination and calibration of claims-based risk-adjustment models for surgical site infections; and (2) the incremental value of adding clinical risk factors to claims-based risk-adjustment models for surgical site infections. Our study included all THAs and TKAs performed at a large tertiary care hospital from January 1, 2002 to December 31, 2009 (total n = 20,171 procedures). Revision procedures for infections were excluded. Comorbidity data were ascertained through administrative records and classified by the Charlson comorbidity index. Clinical details were obtained from the institutional joint registry and patients' electronic health records. Cox proportional hazards regression models were used to estimate the 1-year risk of surgical site infections with a robust sandwich covariance estimator to account for within-subject correlation of individuals with multiple surgeries. The performance of claims-based risk models with and without the inclusion of four clinical risk factors (morbid obesity, prior nonarthroplasties on the same joint, American Society of Anesthesiologists score, operative time) was assessed using measures of discrimination (C statistic, Somers' D xy rank correlation, and the Nagelkerke R(2) index). Furthermore, calibrations of claims-based risk models with and without clinical factors were assessed graphically by plotting the smoothed trends between model predictions and empirical rates from Kaplan-Meier. Discrimination of the claims-based risk models was moderate for the THA (C statistic = 0.662, D xy = 0.325, R(2) = 0.028) and TKA (C statistic = 0.621, D xy = 0.241, R(2) = 0.017) cohorts. Inclusion of four clinical risk factors improved discrimination in both cohorts with significant improvement in the C statistic in the THA cohort (C statistic = 0.043; 95% CI, 0.012-0.074) and in the TKA cohort (C statistic = 0.027; 95% CI, 0.007-0.047). Visual inspection suggested that calibration of the claims-based risk models was adequate and comparable to that of models which included the four additional clinical factors. Claims-based risk-adjustment models for surgical site infections in THA and TKA appear to be adequately calibrated but lack predictive discrimination, particularly with TKAs. The addition of clinical risk factors improves the discriminative ability of the models to a moderate degree; however, addition of clinical factors did not change calibrations, as the models showed reasonable degrees of calibration. When used in the clinical setting, the predictive performance of claims-based risk-adjustment models may be improved further with inclusion of additional clinical data elements.
    Clinical Orthopaedics and Related Research 12/2014; 473(5). DOI:10.1007/s11999-014-4083-y · 2.88 Impact Factor
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    ABSTRACT: Instability in flexion after total knee replacement (TKR) typically occurs as a result of mismatched flexion and extension gaps. The goals of this study were to identify factors leading to instability in flexion, the degree of correction, determined radiologically, required at revision surgery, and the subsequent clinical outcomes. Between 2000 and 2010, 60 TKRs in 60 patients underwent revision for instability in flexion associated with well-fixed components. There were 33 women (55%) and 27 men (45%); their mean age was 65 years (43 to 82). Radiological measurements and the Knee Society score (KSS) were used to assess outcome after revision surgery. The mean follow-up was 3.6 years (2 to 9.8). Decreased condylar offset (p < 0.001), distalisation of the joint line (p < 0.001) and increased posterior tibial slope (p < 0.001) contributed to instability in flexion and required correction at revision to regain stability. The combined mean correction of posterior condylar offset and joint line resection was 9.5 mm, and a mean of 5° of posterior tibial slope was removed. At the most recent follow-up, there was a significant improvement in the mean KSS for the knee and function (both p < 0.001), no patient reported instability and no patient underwent further surgery for instability. The following step-wise approach is recommended: reduction of tibial slope, correction of malalignment, and improvement of condylar offset. Additional joint line elevation is needed if the above steps do not equalise the flexion and extension gaps. Cite this article: Bone Joint J 2014;96-B:1644-8. ©2014 The British Editorial Society of Bone & Joint Surgery.
    12/2014; 96-B(12):1644-8. DOI:10.1302/0301-620X.96B12.34821
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    ABSTRACT: Background. The National Healthcare Safety Network surgical site infections risk models for hip (HPRO) and knee (KPRO) replacement are intended for case-mix adjustment when reporting surgical site infection rates across institutions, but they are not validated in external data sets. Objective. To evaluate the validity of HPRO and KPRO risk models and improvement in risk prediction with inclusion of information on morbid obesity and diabetes mellitus. Design. Retrospective cohort study. Patients. A single-center cohort of 21,941 hip and knee replacement procedures performed between 2002 and 2009. Methods. Discriminative ability was assessed using the concordance statistic (C statistic). Calibration was assessed using the Hosmer-Lemeshow goodness-of-fit tests. Results. The discrimination of HPRO was good, with a C statistic of 0.695 for surgical site infections and 0.749 for prosthetic joint infections. The discrimination of KPRO was worse than that of HPRO, with a C statistic of 0.592 for surgical site infections and 0.675 for prosthetic joint infections. Adding morbid obesity and diabetes mellitus to the HPRO and KPRO risk models modestly improved discrimination. There was no significant evidence of miscalibration based on the Hosmer-Lemeshow tests, but calibration of HPRO models appeared to be better than that of the KPRO models. Conclusions. HPRO performed better than the KPRO in predicting surgical site infections after hip and knee replacements. Both fared well in predicting prosthetic joint infections.
    Infection Control and Hospital Epidemiology 11/2014; 35(11):1323-9. DOI:10.1086/678412 · 3.94 Impact Factor
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    ABSTRACT: Morbid obesity (BMI [body mass index], ≥40 kg/m(2)) is associated with a higher risk of complications, including infection and implant failure, following primary total hip arthroplasty. The purpose of this study was to compare the results of two-stage revision total hip arthroplasty for infection in a morbidly obese patient cohort (BMI, ≥40 kg/m(2)) and nonobese patients (BMI, <30 kg/m(2)). Using an institutional total joint registry, we reviewed the medical records of 653 patients treated with two-stage revision total hip arthroplasty for periprosthetic joint infection over a twenty-year period (1987 to 2007). Patients were stratified according to preoperative BMI. Thirty-three patients (fourteen male and nineteen female) with a BMI of ≥40 kg/m(2) were identified. These patients were matched 1:2 with a cohort of sixty-six patients (twenty-eight male and thirty-eight female) of the same sex and similar age (91% within two years) who were not obese (BMI, <30 kg/m(2)). All patients had a minimum of five years of clinical follow-up (mean, 8.1 years in the morbidly obese group and 10.3 years in the nonobese group). Compared with nonobese patients, morbidly obese patients had significantly greater rates of reinfection (18% compared with 2%, p < 0.005), revision (42% compared with 11%, p < 0.001) and reoperation for any reason (61% compared with 12%, p < 0.001). Prior to surgery, the mean Harris Hip Score had been 50.6 in the morbidly obese group and 48.8 in the nonobese group, and these scores improved significantly in both groups postoperatively (p < 0.01). Morbidly obese patients have markedly elevated risks of reinfection, reoperation, and component resection as well as poorer intermediate-term clinical outcome scores compared with nonobese patients following revision total hip arthroplasty for periprosthetic joint infection. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.
    The Journal of Bone and Joint Surgery 09/2014; 96(18):e154. DOI:10.2106/JBJS.M.01289 · 4.31 Impact Factor
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    ABSTRACT: Small colony variants (SCVs) are naturally occurring subpopulations of bacteria. The clinical characteristics and treatment outcomes of patients with prosthetic joint infection (PJI) caused by staphylococcal SCVs are unknown. This study was a retrospective series of 113 patients with staphylococcal PJI, with prospective testing of archived sonicate fluid samples. SCVs were defined using two-investigator review. Treatment failure was defined as (i) subsequent revision surgery for any reason, (ii) PJI after the index surgery, (iii) prosthesis nonreimplantation due to ongoing infection, or (iv) amputation of the affected limb. There were 38 subjects (34%) with SCVs and 75 (66%) with only normal-phenotype (NP) bacteria. Subjects with SCVs were more likely to have been on chronic antimicrobials prior to surgery (P = 0.048), have had prior surgery for PJI (P = 0.03), have had a longer duration of symptoms (P = 0.0003), and have had a longer time since joint implantation (P = 0.007), compared to those with only NP bacteria. Over a median follow-up of 30.6 months, 9 subjects (24%) with SCVs and 23 (32%) with only NP bacteria experienced treatment failure (P = 0.51). Subjects infected with Staphylococcus aureus were more likely to fail than were those infected with Staphylococcus epidermidis (hazard ratio [HR], 4.03; 95% confidence interval [CI], 1.80 to 9.04). While frequently identified in subjects with PJI and associated with several potential predisposing factors, SCVs were not associated with excess treatment failure compared to NP infections in this study, where they were primarily managed with two-stage arthroplasty exchange.
    mBio 08/2014; 5(5). DOI:10.1128/mBio.01910-14 · 6.88 Impact Factor
  • Arlen D Hanssen
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    ABSTRACT: Where Are We Now?Despite considerable controversy and investigation during the past three decades, the appropriate selection criteria for performing single-stage versus two-stage exchange have not been clearly elucidated. Given the morbidity of two-stage revision for the infected TKA, I certainly understand the motivation to use (or to evaluate) the single-stage approach to this difficult problem. In the current manuscript by Haddad and colleagues, strict patient selection criteria for the use of a single-stage procedure resulting in selection of 28 of 102 patients with infected TKAs are consistent with the majority of earlier studies and current expert opinion. These criteria call for selection of only the healthiest of patients, with more easily treatable micro-organisms, and minimal disruption of anatomy (ie, minimal bone loss and an excellent soft tissue envelope). It is interesting to note that in a highly specialized referral center, this single-stage procedure was performed on a ...
    Clinical Orthopaedics and Related Research 08/2014; 473(1). DOI:10.1007/s11999-014-3799-z · 2.88 Impact Factor
  • Brandon J Yuan, David G Lewallen, Arlen D Hanssen
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    ABSTRACT: Total hip arthroplasty (THA) for the treatment of posttraumatic osteoarthritis (OA) after acetabular fracture has been associated with a high likelihood of aseptic loosening, instability, and infection. Porous metal components may help to address the issue of loosening, but there are few data on the use of porous metal acetabular components for posttraumatic OA after acetabular fracture.
    Clinical Orthopaedics and Related Research 08/2014; 473(2). DOI:10.1007/s11999-014-3852-y · 2.88 Impact Factor
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    ABSTRACT: We previously described a rapid PCR panel targeting bacteria associated with prosthetic joint infection (PJI) for use on biofilms dislodged from explanted hip and knee arthroplasties. Herein, we tested the PCR panel on periprosthetic tissues from 95 subjects undergoing resection knee arthroplasty, all of whom had had tissue cultures performed. A subset also had synovial fluid culture (n = 89) and/or device vortexing and sonication with culture (n = 58), and a subset of these PCR (n = 36) of resulting sonicate fluid, performed. Of the 64 subjects with PJI, 10 and 44 had positive tissue PCR and cultures, respectively, one of whom had a positive tissue PCR with negative tissue cultures. The overall sensitivity of tissue PCR (16%) was much lower than that of tissue (69%), synovial fluid (72%) and sonicate fluid (83%) culture as well as sonicate fluid PCR (78%) (P <0.00001, P <0.00001, P <0.00001, and P = 0.0003, respectively). Periprosthetic tissue PCR, as performed herein, has poor sensitivity for PJI diagnosis.
    Diagnostic Microbiology and Infectious Disease 08/2014; 79(4). DOI:10.1016/j.diagmicrobio.2014.03.021 · 2.57 Impact Factor
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    ABSTRACT: Few registry-based studies in the United States have compared the survivorship of different knee implant designs in total knee arthroplasty. The purpose of this study was to compare differences in survivorship of commonly used tibial implant designs in primary total knee arthroplasty.METHODS: A total of 16,584 primary total knee arthroplasties in 11,992 patients were performed at a single institution from 1985 to 2005. Patients were prospectively followed at regular intervals to ascertain details of subsequent revisions. Overall revision rates and revisions for aseptic loosening, wear, and osteolysis were compared across twenty-two tibial implant designs using Cox proportional hazards regression models adjusting for age, sex, calendar year, and body mass index.RESULTS: In comparison with metal-backed modular implants, all-polyethylene tibial components had a significantly lower risk of revision (hazard ratio, 0.3; 95% confidence intervals: 0.2, 0.5 [p < 0.0001]). The risk reduction with all-polyethylene tibial components was not affected by age, sex, or body mass index. With metal-backed modular tibial designs, cruciate-retaining knees performed better than the posterior-stabilized knees (p = 0.002), but this finding was limited to one specific metal-backed modular tibial component, the Press Fit Condylar design. With all-polyethylene tibial components, there was no survivorship difference between cruciate-retaining and posterior-stabilized designs.CONCLUSIONS: All-polyethylene tibial components were associated with better outcomes than metal-backed modular components. Cruciate-retaining and posterior-stabilized designs performed equally well, except with the Press Fit Condylar design. Obese patients may have superior results with all-polyethylene and posterior-stabilized components.LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
    The Journal of Bone and Joint Surgery 07/2014; 96(14):e121. DOI:10.2106/JBJS.M.00820 · 4.31 Impact Factor
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    ABSTRACT: Total femoral arthroplasty (TFA) is an option to amputation in the setting of excessive bones loss during revision total hip and knee arthroplasty. Twenty non-oncologic TFAs with a minimum of 2years follow-up were retrospectively reviewed. The average clinical follow-up was 73±49months. The incidence of new infection was 25% (5/20), while the overall infection rate was 35% (7/20). The incidence of primary hip instability was 10% (2/20), while the overall instability rate was 25% (5/20). Six patients (30%) required revision. The average pre-operative HHS was 30.2±13.1. The average post-operative HHS was 65.3±16.9. TFA is a viable alternative to amputation in non-oncologic patients with massive femoral bone deficiency. However, TFA performed poorly in the setting of infection and instability.
    The Journal of Arthroplasty 05/2014; 29(10). DOI:10.1016/j.arth.2014.05.012 · 2.37 Impact Factor
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    ABSTRACT: Fungal periprosthetic joint infections (PJIs) are rare. Fewer than 200 cases have been reported in the literature. The characteristics of systemic inflammatory markers and joint aspirate cell count analysis obtained in patients with fungal PJIs have not been fully assessed. The ability to diagnose involvement of fungal PJI preoperatively may optimize the surgical and medical management of these patients. We determined whether preoperative systemic inflammatory markers and total synovial fluid leukocyte count and neutrophil percentage were different between patients with fungal and bacterial PJI. We reviewed the medical records of 44 patients with culture-positive diagnosed fungal PJIs treated at our institution between January 1, 2002, and December 31, 2011, in this study. This represented 1.2% of the total 3822 PJIs treated at our institution during the study period. The mean values for C-reactive protein, erythrocyte sedimentation rate, leukocyte count, and neutrophil percentage of patients with purely fungal PJIs were compared to those of 59 patients with bacterial PJIs treated by one surgeon during the same time period. The mean erythrocyte sedimentation rate values for fungal and bacterial PJIs were 40 mm/hour (95% CI: 30, 50 mm/hour) and 41 mm/hour (95% CI: 33, 49 mm/hour), respectively (p = 0.61). The mean C-reactive protein values for fungal and bacterial PJIs were 42 mg/L (95% CI: 22, 62 mg/L) and 65 mg/L (95% CI: 43, 88 mg/L), respectively (p = 0.42). The mean total nucleated leukocyte counts for fungal and bacterial PJIs were 11,928 (95% CI: 3906, 19,950) with 81% (95% CI: 75%, 88%) neutrophils and 36,901 (95% CI: 21,822, 51,921) with 73% (95% CI: 65%, 81%) neutrophils, respectively (leukocyte count: p = 0.19; neutrophil percentage: p = 0.55). Early detection of fungal PJI is needed, but systemic inflammatory markers and synovial fluid cell count analyses from aspirations do not discriminate whether an infection may be of fungal origin. Level IV, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.
    Clinical Orthopaedics and Related Research 04/2014; 472(11). DOI:10.1007/s11999-014-3631-9 · 2.88 Impact Factor
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    ABSTRACT: Polymerase chain reaction coupled with electrospray ionization mass spectrometry applied to synovial fluid had an 81% sensitivity and a 95% specificity for the diagnosis of prosthetic joint infection.
    Journal of clinical microbiology 04/2014; 52(6). DOI:10.1128/JCM.00570-14 · 4.23 Impact Factor
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    ABSTRACT: Although highly porous metals have demonstrated excellent bone ingrowth properties and so are an intriguing option for fixation in total knee arthroplasty (TKA), some surgeons are skeptical about the durability of uncemented tibial fixation and the potential for soft tissues to adhere to these porous metals and perhaps cause knee stiffness or pain. The purpose of this study was to compare, in the context of a randomized clinical trial, a highly porous metal tibia compared with a traditional modular cemented tibia in terms of survivorship, Knee Society scores, range of motion (ROM), and complications. From 2003 to 2006, 397 patients (age 67.8 ± 8.7 years; 54% female) were randomized to three groups: (1) traditional modular cemented tibia; (2) cemented highly porous metal tibia; and (3) uncemented highly porous metal tibia. The same posterior-stabilized femoral component and patella component were cemented in every case. Stratified randomization was done for surgeon, patient's age, sex, and body mass index. Survivorship at 5 years was compared between the groups, as were Knee Society scores, ROM, and complications. Radiographic assessment included alignment, radiolucency, and implant migration/loosening. Patients were followed until death, revision, or for a minimum of 2 years (mean, 5 years; range, 2-9 years). Four patients were lost to followup before 2 years. Highly porous metal tibias (both uncemented and cemented) were no different from traditional cemented modular tibial modular components in terms of survivorship at 5 years using a intention-to-treat analysis (96.8% [1]; 97.6% [2]; 96.7% [3]; p = 0.59). A per-protocol analysis revealed that no highly porous metal tibia was revised for aseptic loosening. Highly porous metal tibias performed comparably to traditional cemented modular tibias in terms of Knee Society scores, ROM, and the frequency of complications. At 5 years this randomized clinical trial demonstrated that highly porous metal tibias provided comparably durable fixation and reliable pain relief and restoration of function when compared with a traditional cemented modular tibia in TKA. Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
    Clinical Orthopaedics and Related Research 04/2014; DOI:10.1007/s11999-014-3585-y · 2.88 Impact Factor
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    ABSTRACT: Complications involving the knee extensor mechanism and patellofemoral joint occur in 1% to 12% of patients following total knee arthroplasty and have major negative effects on patient outcomes and satisfaction. The surgeon must be aware of intraoperative, postoperative, and patient-related factors that can increase the rate of these problems. This review focuses on six of the most commonly encountered problems: patellar tendon disruption, quadriceps tendon rupture, patellar crepitus and soft-tissue impingement, periprosthetic patellar fracture, patellofemoral instability, and osteonecrosis of the patella. The goals of this report are to (1) review the relevant anatomy of the knee extensor mechanism, (2) present risk factors that may lead to extensor mechanism complications, (3) provide a diagnostic and treatment algorithm for each of the aforementioned problems, and (4) review the specific surgical techniques of Achilles tendon allograft reconstruction and synthetic mesh augmentation. Extensor mechanism disorders following total knee arthroplasty remain difficult to manage effectively. Although various surgical techniques have been used, the results in patients with a prior total knee arthroplasty are inferior to the results in the young adult without such a prior procedure. Surgical attempts at restoration of the knee extensor mechanism are usually warranted; however, the outcomes of treatment of these complications are often poor, and management of patient expectations is important.
    The Journal of Bone and Joint Surgery 03/2014; 96(6):e47. DOI:10.2106/JBJS.M.00949 · 4.31 Impact Factor
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    ABSTRACT: We compared PCR-ESI/MS to culture using sonicate fluid from 431 subjects with explanted knee (n=270) or hip (n=161) prostheses. 152 and 279 subjects had PJI and aseptic failure, respectively. The sensitivity for detecting PJI was 77.6% for PCR-ESI/MS and 69.7% for culture (p=0.0105). The specificities were 93.5 and 99.3%, respectively (p=0.0002).
    Journal of clinical microbiology 11/2013; DOI:10.1128/JCM.03217-13 · 4.23 Impact Factor

Publication Stats

7k Citations
798.31 Total Impact Points

Institutions

  • 1988–2015
    • Mayo Clinic - Rochester
      • • Division of Orthopaedic Surgery
      • • Department of Orthopedics
      Рочестер, Minnesota, United States
  • 2014
    • Hospital for Special Surgery
      • Department of Orthopaedic Surgery
      New York, New York, United States
  • 2002–2014
    • Mayo Foundation for Medical Education and Research
      • • Department of Orthopaedic Surgery
      • • College of Medicine
      Рочестер, Michigan, United States
  • 2012
    • Case Western Reserve University School of Medicine
      Cleveland, Ohio, United States
  • 2009
    • UConn Health Center
      Farmington, Connecticut, United States
  • 2008
    • Sinai Hospital
      Baltimore, Maryland, United States
  • 2006
    • Rochester College
      Rochester, New York, United States
    • OrthoCarolina
      Charlotte, North Carolina, United States
    • Medical University of South Carolina
      • Division of Infectious Disease
      Charleston, SC, United States
  • 2004
    • Rothman Institute
      Philadelphia, Pennsylvania, United States
  • 1999
    • Thomas Jefferson University Hospitals
      Filadelfia, Pennsylvania, United States
  • 1996
    • University of Pennsylvania
      Philadelphia, Pennsylvania, United States