Porous Tantalum Metaphyseal Cones for Severe Femoral and Tibial Bone Defects in Revision Total Knee Arthroplasty are Reliable for Fixation at Mean 5-Year Follow-Up.

BACKGROUND: Porous tantalum metaphyseal cones may facilitate reconstructions of severe bone defects during revision total knee arthroplasty (TKA), but there remains a paucity of data on their outcomes at mean 5 years of follow-up. This study reports the component survivorship, patient satisfaction, functional outcomes, radiographic osseointegration, and complications of revision TKA with porous tantalum metaphyseal cones at mid-term (mean 5-year) follow-up. METHODS: This study included 152 patients who had a mean age of 66 years (range, 33 to 86 years) undergoing revision TKA with porous tantalum metaphyseal cones. Indications for surgery included aseptic loosening (n = 87, 57.3%), second-stage reimplantation for infection (n = 42, 27.6%), osteolysis with well-fixed components (n = 20, 13.2%), and periprosthetic fracture (n = 3, 2.0%). Component survivorship, clinical outcomes, radiographic outcomes, and any complications were recorded. The mean follow-up time was 5.6 years (range, 2.2 to 13.7). RESULTS: Survivorship was 100% when the end point was revision of the metaphyseal cone (no cones were revised) and 83.8% (95% confidence interval: 77.9 to 90.2%) when the end point was reoperation for any reason at 5-year follow-up. Reoperations were performed for infection (n = 10), instability (n = 4), periprosthetic fracture (n = 2), and quadriceps rupture/dehiscence (n = 3). The mean patient satisfaction score was 78.8 ± 11.3 and the mean Forgotten Joint Score was 62.2 ± 16.7 at the final follow-up. The preoperative median University of California at Los Angeles score improved from 2 (interquartile range 2 to 3) to 6 points (interquartile range 5 to 6) (P < .001), and the preoperative Oxford knee score improved from 15.2 ± 3.8 to 39.4 ± 5.1 points (P < .001) at the final follow-up. All metaphyseal cones showed radiographic evidence of osteointegration without any subsidence or loosening. CONCLUSIONS: Porous tantalum metaphyseal cones enabled robust reconstructions of severe femoral and tibial bone defects during revision TKA. These reconstructions were associated with excellent survivorship, improvements in functional outcomes, and reproducible radiographic osseointegration at mean 5-year follow-up. The most common reasons for reoperation were infection and instability.

Clinical Outcomes and Risk Factors for Re-Revision Due to Trunnion Corrosion in Primary Metal-on-Polyethylene Total Hip Arthroplasty.

BACKGROUND: There is a paucity of literature regarding the mid-term (greater than 2 years) outcomes of revision for adverse local tissue reaction to metal debris due to corrosion at the head-neck junction (trunnionosis) in metal-on-polyethylene total hip arthroplasty (THA), and risk factors for re-revision remain largely unknown. We aimed to report the re-revision-free survival and functional outcomes for this patient population and to identify risk factors for re-revision. METHODS: A total of 80 hips (79 patients) with a metal-on-polyethylene THA who had undergone revision for trunnionosis at our institution were included. The mean study follow-up from index trunnionosis revision was 4.6 years (range, 2.0 to 9.4). Kaplan-Meier survival analysis was performed with all-cause re-revision as the end point, and multivariate logistic regression was used to identify risk factors for re-revision. RESULTS: We saw that twenty-one hips (26%) underwent re-revision at a mean of 8.0 months (range, 0.03 to 36.3) after the index trunnionosis revision, most commonly for instability and infection. The two- and five-year all-cause re-revision-free survival rates were 75.0 and 73.2%, respectively. The mean Oxford Hip Score was 33.7 (range, 11 to 48); 76% were satisfied, and 24% were dissatisfied with their hip. Multivariate analysis identified not undergoing a cup revision (odds ratio: 4.5; 95% confidence interval: 1.03 to 19.7) and time from primary THA to the index trunnionosis revision (odds ratio: 0.77; 95% confidence interval: 0.62 to 0.97) as risk factors for undergoing re-revision. CONCLUSIONS: The risk of early re-revision for these patients is high (26%), mostly due to infection and instability, and functional outcomes are fair. Not performing a cup revision appears to be a risk factor for re-revision, as is the shorter time from primary THA to trunnionosis revision. LEVEL OF EVIDENCE: III.

Risk factors for failure of manipulation under anesthesia after total knee arthroplasty.

BACKGROUND: Manipulation under anesthesia (MUA) is a well-established treatment for stiffness after total knee arthroplasty (TKA). Risk factors for failure of MUA remain largely unknown. The primary aim of this study was to identify risk factors for failure of MUA after TKA. METHODS: We performed a retrospective cohort study including 470 patients who underwent MUA after primary TKA with minimum 2 year follow-up. Patients were grouped into success (n = 412) or failure (n = 58) cohorts; failure was defined as flexion < 90° at most recent follow-up or revision for stiffness. The increase in flexion post-MUA for the cohort was calculated. Several clinical, patient, and surgical factors were analyzed using univariate, followed by multivariable logistic regression models to identify independent risk factors associated with failure. RESULTS: The mean increase in flexion was 42° (range 0-115). BMI 30-35 (p = 0.01, odds ratio (OR) 2.42; 95% CI 1.25-4.68) and poorer pre-MUA flexion (p < 0.01, OR 1.43; 95% CI 1.23-1.67) were risk factors for failure. When considering revision for stiffness only, BMI 30-35 (p = 0.01, OR 3.27; 95% CI 1.41-7.61), lower pre-MUA flexion (p < 0.01, OR 1.43; 95% CI 1.18-1.75), and history of prior knee surgery (p = 0.04, OR 2.31; 95% CI 1.06-5.04) were predictors of failure. Time to MUA (p = 0.48), thromboprophylaxis (p = 0.44), pre-operative opioid use (p = 0.34), depression/anxiety (p = 1.0), and several other factors analyzed were not associated with failure. CONCLUSION: In this large cohort, elevated BMI and lower pre-MUA flexion were risk factors for failure of MUA. History of prior knee surgery was an additional predictor of requiring revision for stiffness.

The Desired Oxford Knee Score Obtained Before Total Knee Arthroplasty is Predictive of the Postoperative Oxford Knee Score: A Prospective Study.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

International primary knee arthroplasty registry review: findings from current reports.

INTRODUCTION: International joint registries provide high volumes of information in relation to the performance of total knee arthroplasty on a global scale. Distillation of this data can be challenging, particularly with the establishment of more arthroplasty registries on a yearly basis. We therefore aim to present key information from these registries in relation to primary total knee arthroplasty. The specific questions of interest include: Which fixation type is superior in TKA? Does the level of constraint impact on clinical performance? How do partial knee replacements perform in the registries? Does patellar resurfacing lead to superior results? Are there any specific implants which perform particularly well or poorly? METHODS: A comprehensive review of the major English-speaking knee arthroplasty registries across the globe was performed. Given the expanding large number of registries worldwide, it was not possible to perform a comprehensive review of all registries and so, a detailed review of the major English-speaking knee arthroplasty registries was included. Key trends and developments in implant performance were identified and presented in the current article. RESULTS: Total knee replacements have lower revision rates than both unicompartmental and patellofemoral joint replacement procedures. Patellofemoral joint replacements have the highest failure rate of all knee replacement procedures. Cruciate-Retaining (CR) TKR designs have superior outcomes to Posterior-Stabilized (PS) designs across all registries. Patellar resurfacing appears to confer an advantage over non-resurfaced patellas in primary TKR. CONCLUSION: We present current global trends in the utility and performance of TKA based on data from English-speaking arthroplasty registries.

The Impact of Changing Total Knee Arthroplasty Implants at a High-Volume Institution.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Minimally Invasive Intermuscular Approaches Versus Conventional Approaches in Total Hip Arthroplasty: A Systematic Review and Meta-Analysis.

BACKGROUND: 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. METHODS: 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). RESULTS: 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. CONCLUSION: 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.

A Comparison of Mobile and Fixed-Bearing Unicompartmental Knee Arthroplasty at a Minimum 10-Year Follow-up.

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.

An Early Report of the Use of a Modular Dual Mobility Articulation in Revision Acetabular Reconstruction.

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.

No Difference Between Trabecular Metal Cones and Femoral Head Allografts in Revision TKA: Minimum 5-year Followup.

BACKGROUND: Encouraging clinical results have been reported with the use of femoral head structural allografts and, more recently, trabecular metal cones for the management of large structural defects of the femur and tibia during revision total knee arthroplasty (TKA). However, to our knowledge, there are no published studies comparing these two techniques. QUESTIONS/PURPOSES: Compared with bulk allografts, do trabecular metal cones result in (1) better validated outcomes scores; (2) a lower risk of loosening or revision at 5 years; and (3) fewer surgical complications when used for the management of bone loss in revision TKA? METHODS: Between 2002 and 2008, three surgeons performed 450 TKA revisions, 45 (10%) of which were performed using augmentation of host bone; in those, femoral head allograft was used in 30 (75%) and trabecular metal cones in 15 (25%). From 2002 to 2007, femoral head allografts were used in all patients (28 patients); from 2007 to 2008, trabecular metal augments were used in all patients. There was a period of 1 year (16 knees) in which there was some overlap; during that time, femoral head structural allografts were used in cases in which we were unable to fit the defect or achieve adequate stability with trabecular metal cones. Followup was at a mean of 9 years (range, 5-12 years). No patients were lost to followup. Knee function and quality of life were assessed using the Oxford Knee Score, WOMAC, SF-12, and the UCLA activity score. Radiographs were assessed for signs of loosening. Surgical complications included superficial or deep infections, iatrogenic fractures, symptomatic deep venous thromboses or pulmonary emboli, and blood loss requiring transfusion; these were obtained from our database and from review of patients' charts. RESULTS: The mean Oxford Knee Score in the allograft and trabecular metal cone groups was 91 (SD 10) and 91 (SD 14), respectively (95% confidence interval [CI], 88-94; p = 0.29). Mean WOMAC scores were 94 (SD 10) and 92 (SD 14), respectively (95% CI, 80-105; p = 0.52) and mean UCLA scores were 6 (SD 1.2) and 6 (SD 1.5), respectively (95% CI, 4-8; p = 0.49). Five- and 10-year survivorship of the allografts was 93% (95% CI, 77-98) and 93% (95% CI, 77-99), respectively. Survivorship at a mean of 5 years in the trabecular metal cones group was 91% (95% CI, 56-98). With the numbers available, there were no differences between the groups in terms of the frequency of surgical complications (3% [one of 30] versus 7% [one of 15]; odds ratio, 0.5; p = 0.632). CONCLUSIONS: With the numbers available, we found no difference in pain, function, or repeat revision when comparing femoral head allografts and trabecular metal cones for severe bone defects during revision TKA. However, we used allografts for the larger bone defects. Based on these results, we believe that femoral head allografts and trabecular metal cones can both be used for the management of Anderson Orthopaedic Research Institute Types 2 and 3 defects. Future multicenter studies are required with larger numbers, cost analyses, and a longer duration of followup. LEVEL OF EVIDENCE: Level III, therapeutic study.

Cementless Total Knee Arthroplasty: A State-of-the-Art Review.

¼ The demographic profile of candidates for total knee arthroplasty (TKA) is shifting toward younger and more active individuals.¼ While cemented fixation remains the gold standard in TKA, the interest is growing in exploring cementless fixation as a potentially more durable alternative.¼ Advances in manufacturing technologies are enhancing the prospects for superior long-term biological fixation.¼ Current research indicates that intermediate to long-term outcomes of modern cementless TKA designs are comparable with traditional cemented designs.¼ The selection of appropriate patients is critical to the success of cementless fixation techniques in TKA.¼ There is a need for high-quality research to better understand the potential differences and relative benefits of cemented vs. cementless TKA systems.

The Wagner Cone Stem for Atypical Femoral Anatomy in Total Hip Arthroplasty: A Report of 320 Cases with Minimum 5-Year Follow-up.

BACKGROUND: The Wagner Cone Prosthesis was designed to address complex femoral deformities during total hip arthroplasty (THA), but its mid-term component survivorship and functional outcomes remain undetermined. The objectives of this study were to determine the implant survivorship, patient satisfaction, functional outcomes, osseointegration as seen radiographically, implant subsidence, and complications of THA using the Wagner Cone Prosthesis stem at intermediate-term follow-up. METHODS: This study involved 302 patients with proximal femoral deformities, including developmental hip dysplasia and Legg-Calvé-Perthes disease, who underwent a total of 320 primary THAs using the Wagner Cone Prosthesis. The average age at the time of surgery was 49.4 ± 14.5 years (range, 18.8 to 85.6 years). Patient satisfaction was recorded using a self-administered questionnaire assessing satisfaction in 4 domains. The University of California at Los Angeles (UCLA) activity score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Oxford Hip Score (OHS), the Forgotten Joint Score (FJS), radiographic outcomes, and complications were recorded. The mean follow-up time was 10.1 years (range, 5.2 to 15.5 years). RESULTS: Survivorship of the Wagner Cone Prosthesis was 98.7% (95% confidence interval [CI]: 97.2% to 100%) with stem revision as the end point and 95.8% (95% CI: 93.5% to 98.2%) with reoperation for any reason as the end point at 10 years postoperatively. In total, 3 stems were revised: 2 for infection and 1 for chronic hip dislocation. The median patient satisfaction score was 95 (interquartile range [IQR], 80 to 100), median UCLA score was 6 (IQR, 6 to 7), median WOMAC score was 18 (IQR, 16 to 22), median OHS was 40 (IQR, 36 to 47), and median FJS was 80 (IQR, 76 to 88) at the time of final follow-up. All Wagner Cone stems that were not revised showed radiographic evidence of osseointegration, with a mean stem subsidence of 0.9 ± 0.8 mm at the most recent follow-up. CONCLUSIONS: The use of the Wagner Cone Prosthesis stem in patients with complex femoral anatomy undergoing primary THA is associated with excellent component survivorship, high levels of patient satisfaction, good functional outcomes, and reliable osseointegration with minimal stem subsidence as seen on radiographs at intermediate-term follow-up. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Long-term outcomes of revision total hip arthroplasty with the Zimmer Modular Revision hip system.

Aims: There are limited long-term studies reporting on outcomes of the Zimmer Modular Revision (ZMR) stem, and concerns remain regarding failure. Our primary aim was to determine long-term survival free from all-cause revision and stem-related failure for this modular revision stem in revision total hip arthroplasty (THA). Secondary aims included evaluating radiological and functional outcomes. Methods: We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR system from January 2000 to December 2007. We included 106 patients (108 hips) with a mean follow-up of 14.5 years (2.3 to 22.3). Mean patient age was 69.2 years (37.0 to 89.4), and 51.9% were female (n = 55). Indications for index revision included aseptic loosening (73.1%), infection (16.7%), fracture (9.3%), and stem fracture (0.9%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. At most recent follow-up, Oxford Hip Scores (OHS) were collected, and radiological stem stability was determined using the Engh classification. Results: A total of 17 hips (15.7%) underwent re-revision of any component. Indications for re-revision were stem failure (35.3%; n = 6), infection (29.4%; n = 5), instability (29.4%; n = 5), and acetabular aseptic loosening (5.9%; n = 1). The five- and 15-year all-cause survival was 89.7% (95% confidence interval (CI) 86.7 to 92.7) and 83.3% (95% CI 79.6 to 87.0), respectively. There were six re-revisions (5.6%) for stem failure; five for stem fracture and one for aseptic loosening. The five- and 15-year survival free from stem-related failure was 97.2% (95% CI 95.6 to 98.8) and 94.0% (95% CI 91.6 to 96.4), respectively. At final follow-up, the mean OHS was 36.9 (8.0 to 48.0) and 95.7% (n = 66) of surviving modular revision stems were well-fixed in available radiographs. Conclusion: Femoral revision with the ZMR offers satisfactory long-term all-cause revision-free survival, good survival free of stem-related failure, and favourable clinical outcomes. Stem fracture was the most common reason for stem-related failure and occurred both early and late. This highlights the importance of both early and long-term surveillance for stem-related failure.

High survival of modular tapered stems for proximal femoral bone defects at 5 to 10 years followup.

BACKGROUND: Currently, the two most commonly used options for the revision of femoral components in North America are: cylindrical, nonmodular, cobalt-chromium stems and tapered, fluted, modular, titanium (TFMT) stems. Previous reports have cited high failure rates with cylindrical cobalt chrome stems in large femoral defects but the longer term survival of the fluted stems is unknown. QUESTIONS/PURPOSES: We examined the 5- to 10-year survival of TFMT stems implanted for severe femoral defects. METHODS: We reviewed all 65 patients with severe proximal bone defects revised with the TMFT stem between January 2000 and 2006. Ten were lost to followup and seven were dead, leaving 48 patients for followup at 5 to 10 years (mean, 84 months; range, 60-120 months). All patients completed five quality-of-life (QOL) questionnaires. Radiographs were evaluated for loosening, subsidence, and preservation of proximal host bone stock. RESULTS: Implant survivorship was 90%. No patient underwent revision for either subsidence or loosening. Subsidence occurred in seven patients (average, 12.3 mm) but all achieved secondary stability. Five patients underwent revision as a result of fracture of the stem and all had the original standard stem design, which has since been modified. All five implant fractures occurred at the modular stem junction. Mean QOL outcomes were: WOMAC = 81 (pain), Oxford = 75, SF-12 = 54 (mental) and 38 (physical), UCLA Activity = 4, and satisfaction overall = 73. CONCLUSIONS: Midterm survivorship of modular titanium stems in large femoral defects is high; however, ongoing surveillance of stem junctional fatigue life is required. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The natural history of inflammatory pseudotumors in asymptomatic patients after metal-on-metal hip arthroplasty.

BACKGROUND: Although pseudotumors have been reported in 32% of asymptomatic metal-on-metal hips, the natural history of asymptomatic pseudotumors is unknown. QUESTIONS/PURPOSES: The purpose of this study was to assess changes over time in asymptomatic pseudotumors and the effect of revision on pseudotumor mass. METHODS: Followup ultrasound was performed a mean of 25.8 months (range, 21-31 months) after the detection of 15 pseudotumors and five isolated fluid collections in a cohort of 20 asymptomatic patients (13 metal-on-metal, three metal-on-polyethylene, and four hip resurfacings) [42]. Changes in pseudotumors and fluid collections size and nature, and serum ion levels were determined. RESULTS: Among the 15 nonrevised patients, pseudotumors increased in size in six (four solid and two cystic) of 10 patients, three of which had clinically important increases (13-148 cm(3); 28-74 cm(3); 47-104 cm(3)). Three pseudotumors (one solid and two cystic) disappeared completely (the largest measured 31 cm(3)). One solid pseudotumor decreased in size (24 to 18 cm(3)). In five revised patients, pseudotumors completely disappeared in four patients. The fifth patient had two masses that decreased from 437 cm(3) to 262 cm(3) and 43 cm(3) to 25 cm(3). All revision patients had a reduction of chromium (40.42 µ/L to 2.69 µ/L) and cobalt ions (54.19 µ/L to 0.64 µ/L). Of five isolated fluid collections, four completely disappeared (two metal-on-metal and two metal-on-polyethylene) and one (metal-on-metal) increased from 26 cm(3) to 136 cm(3). CONCLUSIONS: Our observations suggest pseudotumors frequently increase in size in asymptomatic patients with occasional remission of small masses. Revision resulted in remission of pseudotumors.

Outcomes of minimally invasive anterolateral THA are not superior to those of minimally invasive direct lateral and posterolateral THA.

BACKGROUND: There has been considerable interest in minimally invasive surgical (MIS) THA in recent years. The MIS anterolateral approach, or the MIS Watson-Jones approach, is a novel intermuscular abductor-sparing technique. Early reports from case series suggest the potential for superior function and reduced complications; however, the available information from clinical reports is inadequate to suggest surgeons should change from their accepted standard approach. QUESTIONS/PURPOSES: We examined the potential superiority of this anterolateral approach, as judged by quality-of-life (QoL) measures, radiographic parameters, and complications, compared to limited-incision MIS direct lateral and MIS posterolateral approaches. METHODS: We performed a prospective randomized controlled trial involving five surgeons at three centers, recruiting 156 patients undergoing primary THA to receive either the MIS anterolateral or the surgeon's preferred approach (direct lateral or posterolateral). For the 135 patients we report, we collected patient-reported WOMAC, SF-36, Paper Adaptive Test in 5 Domains of Quality of Life in Arthritis Questionnaire [PAT5D], and patient satisfaction scores. We recorded complications and evaluated radiographs for prosthetic component position, subsidence, and fracture. Minimum followup was 24 months (mean, 30 months; range, 24-42 months). RESULTS: QoL and patient-reported satisfaction were similar between groups. Radiographic evaluation demonstrated no differences in acetabular component positioning; however, mean stem subsidence was 4.6 mm for the MIS anterolateral group and 4.1 mm for the alternate group, with differences observed among the three centers for stem subsidence and fracture. One center had increased rate of fracture requiring treatment and need for revision in the MIS anterolateral group. CONCLUSIONS: We found no superiority of the MIS anterolateral approach but observed intersite differences in painful stem subsidence and fracture. We have returned to the standard surgical approaches in use before the trial. LEVEL OF EVIDENCE: Level I, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Patients report improvement in quality of life and satisfaction after hip resurfacing arthroplasty.

BACKGROUND: A number of reconstructive procedures are available for the management of hip osteoarthritis. Hip resurfacing arthroplasty is now an accepted procedure, with implant survivorship comparable to THA at up to 10 years' followup in certain series. Most reports focus on implant survivorship, surgeon-derived results, or complications. Fewer data pertain to patient-reported results, including validated measures of quality of life (QoL) and satisfaction and baseline measures from which to determine magnitude of improvement. Validated patient-reported results are essential to guide patients and surgeons in the current era of informed and shared decision making. QUESTIONS/PURPOSES: We determined whether patients reported improvement in disease-specific, joint-specific, and generic QoL after hip resurfacing arthroplasty; whether patients were satisfied with the results of the procedure; and latest activity level and return to sport. METHODS: We retrospectively reviewed 127 patients (100 men, 27 women) who underwent 143 hip resurfacing procedures between 2002 and 2006. Mean patient age was 52 years. Patients completed the WOMAC, Oxford Hip Score, and SF-12 at baseline and again at minimum 2-year followup (mean, 2.5 years; range, 2-6 years). At latest followup, patients completed a validated satisfaction questionnaire and UCLA activity score. RESULTS: All QoL scores improved (normalized to a 0-100 scale, where 100 = best health state). WOMAC improved from 46 to 95, Oxford Hip Score from 42 to 95, SF-12 (physical) from 34 to 54, and SF-12 (mental) from 46 to 56. Patient satisfaction score was 96. UCLA activity score was 8. CONCLUSIONS: The majority of patients reported improvement in QoL, were very satisfied with their outcome, and returned to a high level of activity after hip resurfacing arthroplasty. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Outcome after isolated polyethylene tibial insert exchange in revision total knee arthroplasty.

We identified 45 knees in 42 patients who had an isolated tibial insert exchange for a failed primary knee arthroplasty with a minimum of 2 years of follow-up. The mean age at revision was 68 years, and the mean time to revision was 80 months. Thirty patients completed follow-up questionnaires (Oxford Knee Score, University Of California Activity Index score, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Short Form 12) with a mean follow-up of 58 months. Patients' current scores were compared with preoperative scores in 14 knees. Four patients (9%) were subsequently revised. Significant improvement was seen in the Oxford Knee Score, Short Form 12 physical component, and all WOMAC domains, but only 58% of patients had a clinically successful result by global WOMAC score. When patients are selected appropriately, an isolated liner exchange can significantly improve the function of the knee.

No difference in quality-of-life outcomes after mobile and fixed-bearing medial unicompartmental knee replacement.

This is a retrospective study comparing the clinical outcomes of mobile vs fixed medial unicompartmental knee replacements. Patients were identified from a prospectively collected database. Demographic data and pre- and postoperative outcomes (Oxford, Western Ontario and McMaster Universities Osteoarthritis Index, Short Form Health Survey-12, and satisfaction) were collected-104 knees (90 patients) with minimum 2-years of follow-up: 37 mobile and 67 fixed-bearing. At baseline, the median age was 60 years (mobile) and 66 (fixed); body mass index was significantly higher (32) for the mobile group than for the fixed (28). At follow-up, the groups differed only in the Oxford score: median 83 (mobile) and 90 (fixed). There is no difference in outcomes between mobile and fixed unicompartmental knee replacements.