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The ability of a group of high-volume arthroplasty surgeons to simultaneously change their preferred primary total knee arthroplasty (TKA) implant of choice to another, has not been explored in the literature to date. The main hypothesis was that such a change could be made with no significant impact on clinical outcomes.This is a retrospective cohort study comparing the last 500 consecutive TKAs implanted of a routinely used TKA implant (NexGen; Zimmer, Warsaw, IN) with the first 500 consecutive TKAs implanted of a newly adopted TKA implant (Triathlon; Stryker, Mahwah, NJ) at an institutional level. Primary outcomes of importance included all complications that occurred either intraoperatively or early postoperatively, early all-cause revision rate, and early reintervention rate.There was a 1.2% (n = 6) complication rate in the NexGen cohort compared to 0.8% (n = 4) in the newly adopted Triathlon cohort (P = .75). The rate of intraoperative fracture was 1% in the NexGen cohort and 0.6% in the Triathlon cohort (P = .72). The early all-cause revision rate for the NexGen TKA was 1% (n = 5) compared to 0.8% (n = 4) in the Triathlon cohort (P = 1.0). The manipulation under anesthesia (MUA) rate in the NexGen cohort was 2.4% compared to 4.6% in the Triathlon cohort (P = .058). The only predictor variable associated with MUA rate was American Society of Anesthesiologists grade, where there was a significantly lower rate of MUA with a higher American Society of Anesthesiologists grade (P = .042).It is possible to implement the institution-wide adoption of an established, high-performing TKA implant without any negative implications in relation to early revision rates, perioperative complication rates, and reintervention rates. This study is the first of its kind to be reported in the literature.

The relationship between patient expectations and patient-reported outcome measures (PROMs) after total knee arthroplasty (TKA) is not well understood. The purpose of the study was to test the influence of desired knee function on postoperative perceived knee function 1 year after TKA.A total of 102 patients undergoing primary TKA were available for data analyses. Preoperatively, patients completed the Oxford Knee Score (OKS) twice, one representing preoperative function (preoperative OKS); the second representing desired function after TKA (desired OKS). Western Ontario and McMaster Universities Arthritis Index (WOMAC), University of California, Los Angeles (UCLA) Activity score, Hospital for Special Surgery Knee Replacement Expectations Survey (HSS-KRES), Patient Health Questionnaire-9, and EuroQol-visual analogue scales were obtained preoperatively. One year after surgery, all surveys besides the UCLA activity score and HSS-KRES were repeated. The associations between postoperative OKS and WOMAC versus desired OKS and HSS-KRES were assessed using multivariable linear regression models, wherein linear regression coefficients represent the additive effect on the mean postoperative PROM.The desired OKS was independently associated with the postoperative OKS (linear regression coefficient = 0.43; P = .011), that is, each point increase in desired OKS yielded a 0.43 increase in postoperative OKS. The preoperative OKS showed no association with postoperative PROMs. Desired OKS was correlated with postoperative WOMAC (coefficient = -0.67; P = .014). The HSS-KRES was not associated with the postoperative OKS (coefficient = -0.005; P = .965) or WOMAC (coefficient = 0.18; P = .288).In TKA patients, higher preoperative desired function predict greater postoperative PROMs. Effects of preoperative expectations on outcomes are independent of patient demographics or preoperative function.

To date, the literature has not yet revealed superiority of Minimally Invasive (MI) approaches over conventional techniques. We performed a systematic review to determine whether minimally invasive approaches are superior to conventional approaches in total hip arthroplasty for clinical and functional outcomes. We performed a meta-analysis of level 1 evidence to determine whether minimally invasive approaches are superior to conventional approaches for clinical outcomes.All studies comparing MI approaches to conventional approaches were eligible for analysis. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adhered to throughout this study. Registries were searched using the following MeSH terms: 'minimally invasive', 'muscle-sparing', 'THA', 'THR', 'hip arthroplasty' and 'hip replacement'. Locations searched included PubMed, the Cochrane Library, ClinicalTrials.gov, the European Union (EU) clinical trials register and the International Clinical Trials Registry Platform (World Health Organisation).Twenty studies were identified. There were 1,282 MI total hip arthroplasty (THAs) and 1,351 conventional THAs performed. There was no difference between MI and conventional approaches for all clinical outcomes of relevance including all-cause revision (P = .959), aseptic revision (P = .894), instability (P = .894), infection (P = .669) and periprosthetic fracture (P = .940). There was also no difference in functional outcome at early or intermediate follow-up between the two groups (P = .38). In level I studies exclusively, random-effects meta-analysis demonstrated no difference in aseptic revision (P = .461) and all other outcomes between both groups.Intermuscular MI approaches are equivalent to conventional THA approaches when considering all-cause revision, aseptic revision, infection, dislocation, fracture rates and functional outcomes. Meta-analysis of level 1 evidence supports this claim.

Background The purpose of this prospective matched paired study is to compare the in vivo migration patterns using Ein Bild Roentgen Analyze femoral component of shortened vs standard-length stems cemented line-to-line in primary total hip arthroplasty (THA) at 2-year follow-up. Methods We prospectively included the first 50 consecutive primary cemented THAs in 50 patients using a 12% shortened stem (AmisK group) of which design was derived from the original Charnley-Kerboull (CK) femoral components. These 50 patients were matched paired to 50 patients from a historical series of patients who underwent primary THAs using standard-length CK stems (CK group) with available long-term results, including Ein Bild Roentgen Analyze femoral component data at 2-year follow-up. Results Body mass index was significantly higher (P = .007) in the AmisK vs the CK group. At the 2-year follow-up, the mean subsidence was 0.65 mm (0-1.40) in the AmisK group vs 0.68 mm (0.07-1.43) in the CK group (P = .73). When using a 1.5-mm threshold, none of the stems in either group was considered to have subsided. Femoral cortical thickening in zones 3 and 5 occurred in 6 of the 50 hips (12%) in the AmisK group vs 20 (40%) of the 50 hips in the CK group (P = .003). Conclusion Our study showed that a shortened highly polished double-tapered stem cemented line-to-line provided similar results including minimal subsidence as its standard-length counterpart, with significantly less distal femoral cortical thickening. However, longer term survival analysis still needs to be determined.

Background The long-term survivorship and functional outcomes of the mobile-bearing (MB) compared to the fixed-bearing (FB) unicompartmental knee arthroplasty (UKA) implant design remain a topic of debate. The aim of the current study was to compare the survivorship and functional outcomes of MB and FB UKA at a minimum 10-year follow-up. Methods We retrospectively reviewed 106 consecutive medial UKAs (89 patients) from our institution with a minimum 10-year follow-up. The 38 MB and 68 FB knees had follow-up of 14.2 years (12.9-15.5) and 11.5 years (10.2-15.1), respectively. Validated patient-reported outcomes and radiographs were evaluated as were etiology, timing, and complexity of revision. Kaplan-Meier 10-year survival was calculated with revision to total knee arthroplasty as the end point. Results The 10-year survival was 82.9% (95% confidence interval [CI] 65.8-91.9) for MB and 90.9% (95% CI 79.4-96.2) for FB UKA (P = .102), and 88.0% (95% CI 79.3-93.2) for the entire cohort. Patient outcomes were similar between groups, as were timing and etiologies for revision to total knee arthroplasty. One-third of revisions required either stems or tibial augments, and of these, all were of MB design. Conclusion Survival and functional outcomes were similar between MB and FB designs. One-third of revisions required either stems or augments, all were of MB design.

Background Aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) development (including pseudotumors) secondary to metal debris generation around total hip arthroplasties is a well-recognized histopathologic phenomenon. Emerging data have highlighted a similar potential concern around TKAs although the body-of-knowledge has largely been limited to individual case reports or small retrospective case series. This study sought to establish the prevalence of pseudotumors or high-grade ALVALs seen at the revision of primary TKAs and to establish the correlation between histologic ALVAL grade and patient-reported functional outcome measures. Methods The findings of 321 non-infective (aseptic) patients undergoing unilateral revision knee surgery, at a high-volume tertiary referral center, were reviewed. Each case was independently histologically classified. Complete patient-reported functional outcome measures were available for 134 patients (42%) allowing correlation between functional performance and histopathology results. Results Five distinct pseudotumors and a further 18 high-grade ALVALs were histologically identified representing 1.6% and 5.6% of the cohort, respectively. When compared by histologic grade, Oxford Knee Score and Western Ontario and McMaster University’s Osteoarthritis Index suggested a high correlation between ALVAL grade and functional knee scores. Conclusion These findings suggest a prevalence of pseudotumors or high-grade ALVALs at revision TKA surgery of >7%. This unexpectedly high result may contribute insight into the previously under-appreciated significance of metal debris-related local tissue reactions around TKAs. The findings also demonstrate a strong near-linear inverse relationship between patient-reported clinical knee performance and the underlying histologic grade of local tissue reaction. These results have potential management implications for patients with underperforming TKAs and should prompt consideration of an ALVAL secondary to metallosis in the differential diagnosis. Level of Evidence This is a retrospective cohort study with Level III evidence.

Background Splined conical stems offer design features that facilitate their use in the misshapen, dysplastic proximal femur. Methods This study assessed the survivorship of a conical prosthesis when applied to secondary coxarthrosis because of a range of pathologies. Fifty-one prostheses were implanted in 50 patients with a mean age of 50 (range, 15-80) and a median follow-up of 34 months (range, 24-73 months). Indications for the stem included developmental (36), neuromuscular (7), post-traumatic or surgical (7), and inflammatory conditions (1). Survivorship, functional outcome (WOMAC [Western Ontaria and McMaster University Osteoarthrits Index], Oxford Hip Score, and UCLA [University of California Los Angeles]), health status (short form-12 [SF-12]), satisfaction, and osseointegration were determined. Results Survivorship for aseptic loosening was 100% at 2 years and 98.04% for septic revision. Eight patients required reoperation, 4 for instability, and 1 each for infection, impingement, adverse reaction to metal debris, and pelvic insufficiency fracture. The mean WOMAC score was 85 (standard deviation [SD], 18), the mean Oxford Hip Score 84 (SD, 18), the mean physical SF-12 score was 48.3 (SD, 8.6), and the mean mental SF-12 was 53.7 (SD, 9.2), the mean satisfaction score was 91.5 (SD, 3.9), and the mean UCLA was 6 (SD, 1.6). All femoral components demonstrated osseointegration. Conclusion The cone femoral prosthesis demonstrates excellent early survival and osseointegration when applied to the challenging femur. Because of these encouraging results, we recommend this prosthesis be considered for the small, abnormal femur in primary hip arthroplasty.

Background Instability remains one of the main problems after revision hip surgery. The aim of this study was to review the clinical, radiological, and patient-reported outcomes with the use of modular dual-mobility articulation for revision acetabular reconstruction and investigate the risk of fretting corrosion by measuring serum trace metal ion levels. Methods Sixty consecutive patients with a minimum of 24-month follow-up after the insertion of a modular dual-mobility (Stryker, Mahwah, NJ) cup at the time of revision hip surgery were identified. Follow-up included clinical and radiological patient review and functional outcome measures, and a subset of patients had their metal ion (cobalt and chromium) levels checked. Results At the most recent follow-up, 5 patients had died, 3 patients have been revised because of ongoing instability, and 3 patients have had revision surgery due to infection. Overall functional outcome (mean Western Ontario and McMaster Universities Osteoarthritis Indexfunction 76, University of California, Los Angeles 5.6, mean Oxford 74.7, Short Form-12 physical 41.6/mental 53.3) and overall pain relief (mean Western Ontario and McMaster Universities Osteoarthritis Index pain score 78.3) scores were good. The mean satisfaction score was 78 of 100. The median serum trace metal chromium and cobalt levels at the most recent follow-up were 0.4 µg/L (range 0.1-6.1 µg/L) and 0.42 µg/L (range 0.21-9.42 µg/L), respectively. The survival with revision as the end point was 90%. Conclusions Dual-mobility cups with modularity represent an excellent option for the patient having revision hip surgery at high risk of instability. This series presents good patient-reported outcome measures and a low complication and revision rate.

An intraoperative imaging tool for total knee arthroplasty could help avoid poor clinical outcomes related to malalignment. We investigated the feasibility of using isocentric (ISO-C) fluoroscopic imaging for this purpose. Three-dimensional ISO-C and computed tomographic (CT) images were acquired from 6 cadaveric specimens implanted with standard knee arthroplasty components and analyzed to determine rotational alignments. In comparison with standard CT measures, the ISO-C–based measures had overall accuracies (determined as root mean square error) of 0.8° and 1.3° and corresponding SDs of 1.3° and 1.4° for the femoral and tibial components, respectively. With ISO-C imaging, it is possible to measure rotational alignment in knee arthroplasty with accuracy and repeatability comparable with CT. Isocentric imaging has strong potential as an intraoperative tool to accurately align arthroplasty components.

Background Revision hip arthroplasty for metal-on-metal arthroplasty (MOMA) in the presence of an adverse local tissue reaction (ALTR) has been associated with compromised outcomes. We hypothesized that revision of MOMA for painful micromotion of the cup, in the absence of ALTR, would have a more favorable outcome. Methods We reviewed our database for Durom acetabular shell revision with minimum 24 months (24 months to 8 years) follow-up. Patients with a diagnosis of painful micromotion in the absence of pseudotumor was identified. Results At mid-term follow-up, 71 patients had undergone revision of a Durom MOMA. Twenty-seven of these (38%) were for painful micromotion (9 total hip arthroplasty, 18 hip resurfacing) of the cup alone. Following revision surgery, all patients reported resolution of the preoperative pain, as well as satisfactory outcome measures (mean scores: The Western Ontario and McMaster Universities Arthritis Index [WOMAC] 84.6, oxford hip score 84.7, Short Form Health Survey (SF-16) 51, University of California, Los Angeles (UCLA) 7.3). Radiologically, all cases demonstrated osseointegration of the revision shells; 1 case had zone-3 radiolucency that was nonprogressive. One patient had a dislocation treated by closed reduction at 10 weeks. Conclusion Revision MOMA for painful micromotion of the shell in the absence of ALTR is not similar to revision for ALTR and is associated with predictable improvement in pain and quality of life.

The use of femoral head structural allograft (FHSA) for the management of massive bony defects during revision total knee arthroplasty (TKA) is well documented in the literature. The purpose of this study was to compare the clinical outcomes of patients undergoing revision (TKA) with FHSA to those without. All patients undergoing revision TKA between January 2000 and August 2005 were reviewed. Two cohorts were generated: a study cohort—revision TKA using FHSA (n = 24)—and control cohort—revision TKA without FHSA (n = 48). The 2 study cohorts groups were comparable. All patients completed validated outcome questionnaires. The FHSA cohort was found to have significantly better outcome scores. This study demonstrates improved clinical outcomes for patients undergoing revision TKA using a structural allograft compared with those without.

The purpose of this study was to evaluate and compare the quality of life and satisfaction outcomes of patients undergoing primary and revision total knee arthroplasty (TKA). Sixty revision and 199 primary TKA patients were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Oxford-12 Knee Score, Short Form-12, and patient-reported satisfaction. Baseline preoperative scores demonstrate that revision TKA patients have inferior quality of life across all measures (WOMAC, Oxford-12, and Short Form-12) in comparison with primary TKA patients (P < .05). At follow-up revision, TKA patients continue to have inferior outcomes (P < .05) in comparison with primary TKA patients. When adjusting for confounding factors in regression analyses, revisions are inferior to primary TKA by 8.6 (95% confidence interval, 2.7-14.6) normalized WOMAC units.

Nineteen patients with a worker's compensation board (WCB) claim treated by unicompartmental knee arthroplasty for medial compartment osteoarthritis were compared to 20 patients who had no WCB claim. In WCB patients, the mean Knee Society Score (KSS) improved from 47.4 to 76.9; the mean Knee Society function score, from 43.8 to 75; and the mean Knee society pain score, from 6.9 to 29.4. In non-WCB patients, the mean KSS improved from 43.3 to 90.7; the mean Knee Society function score, from 44.7 to 90; and the mean Knee Society pain score, from 3.6 to 41.7. The difference in improvement of KSS between the two groups was significant (P = .008). The postoperative KSS in the non-WCB patients was significantly higher than that of the WCB group (P = .007). There was no difference between the incidences of conversion to total knee arthroplasty.

The purpose of this study was to assess the effect of 2 revision reconstructive interventions on patellofemoral joint mechanics in comparison to control. We flexed 8 cadaver knee specimens from 0 degrees to 60 degrees of flexion in a test rig designed to simulate weight-bearing flexion and extension (Oxford rig). Quadriceps tendon extensor force and patellar kinematics were recorded for control total knee arthroplasty (TKA) (normal primary TKA with patella resurfaced) and then for each of the 2 revision patellar interventions (after patelloplasty of typical revision knee patellar bone defect to leave a simple bony shell, and after TKA with augmentation patella resurfacing). Our results demonstrate that patellar kinematics and quadriceps extensor force are optimized when the patella is reconstructed to normal anteroposterior thickness.

The objective is to evaluate the reliability of patients' recall of preoperative pain and function during the immediate postoperation period after total hip arthroplasty. A prospective cohort of 104 patients completed a survey about their quality of life before operation, and recalled preoperative status at 3 days, 6 weeks, and 12 weeks after operation. Quality of life was measured by the Western Ontario and McMaster University Osteoarthritis Index, the Oxford-12 hip score, and the 12-item Short-Form score. The intraclass correlation coefficient and Spearman correlation coefficient were used to compare preoperative quality of life scores to the scores recalled. The reliability of recall remained high up to 3 months postoperation. Patients are able to accurately recall their preoperative function for up to 3 months after total hip arthroplasty.

It remains controversial whether patients' pain, function, and satisfaction are affected in revision total knee arthroplasty by patellar prosthetic resurfacing. This is a retrospective, comparative cohort study to evaluate this. One hundred twenty-six patients who underwent total knee arthroplasty revision were identified. After revision, the presence or absence of a patellar prosthesis was ascertained. At a minimum of 2 years' follow-up, pain and function were assessed by Western Ontario and McMaster Universities Osteoarthritis Index, Oxford-12, Short-Form 12, and patient satisfaction questionnaires in 110 patients (58 with patellar component, 52 bony shell). Univariate and multivariate analyses demonstrated no significant difference between the 2 cohorts for Western Ontario and McMaster Universities Osteoarthritis Index pain, function, Oxford-12, and satisfaction outcomes. The absence of a patellar prosthesis does not appear to significantly affect pain, function, or satisfaction outcomes after revision total knee arthroplasty.

The differences between the pneumatic compression thromboprophylaxis delivered after elective total hip arthroplasties and that was expected were quantified before (49 patients) and after a concerted nursing education program (30 patients) that was designed to ensure maximum compliance and to verify the correct application of the devices. The expected therapy was not delivered to any of the patients monitored. Therapy was delivered only an average of 77.8% of the time during the expected treatment periods. During 99.9% of the expected therapy times, values of key outcomes-related parameters of the therapy delivered to the patients varied by >10% from expected values. These variations were not reduced significantly by medical and nursing education. This variation may be a significant confounding factor in comparatively evaluating thromboembolic disease outcome reports.

Sixty patients were prospectively assessed using the Western Ontario and McMaster Osteoarthritis Index (WOMAC) scale for osteoarthritis of the hip and the Short Form 36 (SF-36) general health status scale as well as the expectation WOMAC, which asked patients to estimate how they expected to feel 6 months after revision hip arthroplasty. There was a wide range of expectations, but we were unable to find any significant correlation between the patients' preoperative pain and stiffness levels and their expectations for pain and stiffness after revision hip arthroplasty. There was no significant correlation between the SF-36 scores and the patients' expectations. Our findings suggest that the expectations of patients awaiting revision hip arthroplasties are high and are not related closely to the level of preoperative disability.

This study assessed the reliability and validity of a new classification system for fractures of the femur after hip arthroplasty. Forty radiographs were evaluated by 6 observers, 3 experts and 3 nonexperts. Each observer read the radiographs on 2 separate occasions and classified each case as to its type (A, B, C) and subtype (B1, B2, B3). Reliability was assessed by looking at the intraobserver and interobserver agreement using the kappa statistic. Validity was assessed within the B group by looking at the agreement between the radiographic classification and the intraoperative findings. Our findings suggest that this classification system is reliable and valid. Intraobserver agreement was consistent across observers, ranging from 0.73 to 0.83. There was a negligible difference between experts and nonexperts. Interobserver agreement was 0.61 for the first reading and 0.64 for the second reading by kappa analysis, indicating substantial agreement between observers. Validity analysis revealed an observed agreement kappa value of 0.78, indicating substantial agreement. This study has shown that this classification is reliable and valid.

A total of 202 revision hip arthroplasties in 178 patients, over a 2-year period, were evaluated prospectively. Intraoperative Gram stains were obtained from periprosthetic tissues in all cases. Of these, a definitive diagnosis of infection, using defined criteria, was established in 35 cases. Of these 35 patients, 17 had received antibiotics before surgery. The intraoperative cultures were positive in 8 of the 17 patients who had received antibiotics and 17 of the 18 patients who had not received preoperative antibiotics. In 1 infected case, intraoperative cultures of periprosthetic tissues failed to reveal bacterial growth, despite the fact that the patient received no preoperative antibiotics. Overall, there were 5 true-positive Gram stain results, 172 true-negative results, 3 false-positive results, and 22 false-negative results. The sensitivity of the Gram stain was 19%, specificity was 98%, predictive value of a positive test was 63%, and predictive value of a negative test was 89%. These results suggest that the intraoperative Gram stain is not a sensitive tool for the diagnosis of infection and should not be used when attempting to diagnose infection intraoperatively.