Search

Background: There has been decreased use of anatomic total shoulder arthroplasty (aTSA) because reverse TSA (rTSA) is increasingly being used for the same indications. Although short-term studies generally have not found survivorship differences between these implant designs, these studies are often small and their follow-up is limited to the short term. Likewise, the degree to which patient characteristics (such as gender, age, and American Society of Anesthesiologists [ASA] score) may or may not be associated with survivorship differences calls for larger and longer-term studies than is often possible in single-center designs. Large national registry studies may be able to help answer these questions.Questions/purposes: By analyzing a large Australian registry series of primary aTSAs with cemented all-polyethylene glenoids and rTSA for osteoarthritis (OA), we asked: (1) Is the revision risk for OA higher for aTSA with all-polyethylene glenoids or for rTSA, adjusting for patient characteristics such as age, gender, ASA score, and BMI? (2) Is the patient's gender associated with differences in the revision risk after controlling for the potentially confounding factors of age, ASA score, and BMI?Methods: In this comparative, observational registry study performed between January 1, 2015, and December 31, 2019, all primary aTSAs with all-polyethylene glenoids and rTSA for OA as determined by the treating surgeon and reported to our national registry formed two groups for analysis. The study period was set to time-match for the collection of ASA score and BMI in 2012 and 2015, respectively. Our registry enrolls more than 97% of all shoulder arthroplasties undertaken in Australia. There were 29,294 primary shoulder arthroplasties; 1592 hemiarthroplasties, 1876 resurfacing and stemless shoulders, 269 stemmed, and 11,674 reverse shoulder arthroplasties were excluded for other diagnoses. A total of 1210 metal-backed glenoids in stemmed aTSA for OA were excluded. A total of 3795 primary aTSAs with all-polyethylene glenoids and 8878 primary rTSAs for OA were compared. An aTSA with an all-polyethylene glenoid and rTSA were more likely to be performed in women (56% and 61% of patients, respectively). The mean age was 69 ± 8 years for aTSA with all-polyethylene glenoids and 74 ± 8 years for rTSA. One aTSA for OA was performed in a patient with an unknown glenoid type. The ASA score (n = 12,438) and BMI (n = 11,233) were also recorded. The maximum follow-up was 5 years for both groups, and the mean follow-up was 2.6 ± 1.4 years for aTSA with all-polyethylene glenoids and 2.1 ± 1.4 years for rTSA. The endpoint was time to revision (all causes), and the cumulative percent revision was determined using Kaplan-Meier estimates of survivorship (time to revision) and HRs from Cox proportional hazard models that were adjusted for age, gender, ASA score, and BMI category.Results: Overall, there were no differences in the 4-year cumulative percent revision between the groups; the 4-year cumulative percent revision was 3.5% for aTSA with all-polyethylene glenoids (95% CI 2.9%-4.2%) and 3.0% for rTSA (95% CI 2.6%-3.5%). There was an increased risk of revision of rTSA compared with aTSA using all-polyethylene glenoids in the first 3 months (HR 2.17 [95% CI 1.25-3.70]; p = 0.006, adjusted for age, gender, ASA score, and BMI). After that time, there was no difference in the rate of revision, with the same adjustments. In the first 3 months, men undergoing rTSA had a higher rate of revision than men with aTSA using all-polyethylene glenoids (HR 4.0 [95% CI 1.72-9.09]; p = 0.001, adjusted for age, BMI, and ASA). There was no difference between men in the two groups after that time. Women with aTSA using all-polyethylene glenoids were at a greater risk of revision than women with rTSA from 3 months onward (HR 2.77 [95% CI 1.55-4.92]; p < 0.001, adjusted for age, BMI, and ASA), with no difference before that time.Conclusion: Given the absence of survivorship differences at 4 years between rTSA and aTSA, but in light of the differences in the revision risk between men and women, surgeons might select an aTSA with an all-polyethylene glenoid to treat OA, despite the current popularity of rTSA. However, there are survivorship differences between genders. Future studies should evaluate whether our comparative findings are replicated in men and women undergoing aTSA with all-polyethylene glenoids and rTSA for primary diagnoses such as rheumatoid arthritis or post-traumatic arthritis, and whether there are functional differences between the two implant designs when used for OA.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Well-validated data from arthroplasty registries provide an opportunity to understand contemporary use of revision hip replacement at a national level. Such information can underpin health-care resource allocation and surgical workforce planning. The purposes of the present study were to describe the demographic characteristics of patients managed with revision hip replacement surgery in Australia and to examine changes in the lifetime risk of revision hip replacement over a decade.Methods: Deidentified individual-level data on all revision hip replacement procedures performed in Australia from 2007 to 2017 were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. Life tables and population data were sourced from the Australian Bureau of Statistics. The lifetime risk of revision surgery each year was estimated with use of a standardized approach, with separate calculations for males and females.Results: A total of 46,086 revision hip replacement procedures were performed from 2007 to 2017. The median age at the time of surgery was 72 years (interquartile range, 63 to 80 years). While loosening or lysis became less frequent reasons for revision over time (from 51% in 2007 to 28% in 2017), revision hip replacement for infection became increasingly common (from 14% in 2007 to 25% in 2017). Revisions for metal-related pathology peaked in 2011. Utilization rates were highest for males ≥80 years of age (127.9 procedures per 100,000 population in 2017). Although a small rise was evident in 2011 and 2012 (to 2.39% and 2.22%, respectively), the lifetime risk of revision hip replacement in females decreased from 1.90% (95% confidence interval [CI], 1.82% to 1.99%) in 2007 to 1.74% (95% CI, 1.66% to 1.82%) in 2017. A similar pattern was evident for males; the lifetime risk was 1.78% (95% CI, 1.69% to 1.86%) in 2007 and 1.57% (95% CI, 1.49% to 1.65%) in 2017.Conclusions: These data enable us to understand the epidemiology of revision hip replacement in Australia, including the shifting clinical indications for this procedure. At a population level, the lifetime risk of revision hip replacement remains low at <1 in 50 people in 2017. These methods can be utilized for population-level surveillance of revision burden and to enable between-country benchmarking.Level Of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: The Birmingham Hip Resurfacing (BHR) prosthesis is the most commonly used metal-on-metal hip resurfacing arthroplasty device. The current manufacturer-recommended target demographic for the BHR is male patients, younger than 65 years requiring a femoral head size of ≥ 50 mm. Female patients, older patients, and individuals with smaller femoral-head diameter (≤ 50 mm) are known to have higher revision rates. Prior studies suggest that the survivorship of the BHR when used in the target demographic is comparable with that of primary conventional THA, but comparing survivorship of the most durable hip resurfacing arthroplasty device to the survivorship of all conventional THA prostheses is not ideal because the THA group comprises a large number of different types of prostheses that have considerable variation in prosthesis survival. A more informative comparison would be with the THA implants with the best survivorship, as this might help address the question of whether survivorship in the BHR target population can be improved by using a well-performing conventional THA.Questions/purposes: We compared the difference in cumulative percent revision, reasons for revision and types of revision for procedures reported to the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) using the BHR prosthesis (femoral-head size > 50 mm) and three conventional THA prostheses identified as having the lowest 10-year cumulative percent revision in the currently recommended BHR target population to ask: (1) Does the BHR have a lower cumulative revision rate than the group of three conventional THA prostheses? (2) Is there a difference in the revision diagnosis between the BHR and the three best conventional THA prostheses? (3) What is the difference in the components used for a revision of a BHR compared with the three best conventional THA prostheses?Methods: Data reported to the AOANJRR between September 1, 1999 and December 31, 2018 was used for this analysis. This study period includes almost the entire use of the BHR in Australia. The AOANJRR is a large national joint registry with almost 100% completeness, high accuracy, rigorous validation, and little to no loss to follow-up. The study population included males younger than 65 years that had received one hip replacement procedure for osteoarthritis. All patients with bilateral procedures, no matter the time interval between hips, were excluded. Only BHR prostheses with a femoral-head size ≥ 50 mm and conventional THA prostheses with femoral head sizes ≥ 32 mm and either ceramic-on-ceramic or metal, ceramic, ceramicized metal-on-crosslinked polyethylene (XLPE) bearings were included. These femoral head sizes and bearings were selected because they reflect modern conventional THA practice. There is no difference in the revision rate of these bearings in the AOANJRR. There were 4790 BHR procedures and 2696 conventional THA procedures in the study group. The mean (± SD) age for BHR procedures was 52 ± 7.8 years and 56 ± 7.1 years for conventional THA procedures. All comparative analyses were adjusted for age. Other demographics data including American Society Anesthesiologists (ASA) score and BMI were only included in AOANJRR data collection since 2012 and 2015, respectively, and have not been included in this analysis because of the low use of BHR in Australia since that time. The maximum follow-up was 18.7 years for both groups and mean follow-up of 11.9 years for the BHR and 9.3 years for the conventional THA group. Revision rates were determined using Kaplan-Meier estimates of survivorship to describe the time to the first revision, with censoring at the time of death or closure of the database at the time of analysis. A revision was defined as removal, replacement or addition of any component of a joint replacement. Revisions can be further classified as major revisions (removal of a component articulating with bone-usually the stem and/or the shell) or minor revisions (removal of other components-usually the head and/or the liner). The unadjusted cumulative percent revision after the primary arthroplasty (with 95% confidence intervals) was calculated and compared using Cox proportional hazard models adjusted for age.Results: The BHR prosthesis had a statistically higher rate of all-cause revision at 17 years than the selected conventional THA prostheses (HR 2.77 [95% CI 1.78 to 4.32]; p < 0.001). The revision diagnoses differed between the groups, with the BHR demonstrating a higher revision rate for loosening after 2 years than the conventional THA protheses (HR 4.64 [95% CI 1.66 to 12.97]; p = 0.003), as well as a higher fracture rate during the entire period (HR 2.57 [95% CI 1.24 to 5.33]; p = 0.01). There was a lower revision rate for infection for the BHR compared with the THA group in the first 5 years, with no difference between the two groups after this time. All revisions of the BHR were major revisions (such as, removal or exchange of the femoral and/or acetabular components) and this occurred in 4.5% of the primary BHR procedures. Major revision was the most common type of revision for primary THA accounting for 1.7% of all primary THA procedures. Minor revisions (head, inset or both) were undertaken in a further 0.6% of primary THA procedures.Conclusions: Given the increasing revision risk of the BHR compared with better-performing conventional THA prostheses in the target population, we recommend that patients be counseled about this risk. We suggest that a THA with proven low revision rates might be the better choice, particularly for patients who are concerned about implant durability. Well-controlled prospective studies that show appreciable clinically important differences in patient-reported outcomes and functional results favoring the BHR over conventional THA prostheses using modern bearings are needed to justify the use of the BHR in view of this revision risk.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: TKA generally has excellent long-term survivorship. When a new knee system supersedes a previous model, increased survivorship, improved functional performance, or both may be expected, because key areas of design modification are often targeted to address wear, stability, and the patellofemoral articulation. However, not all design changes are beneficial, and to our knowledge, knee arthroplasty has not been systematically evaluated in the context of design changes that occur during the development of new knee arthroplasty systems.Questions/purposes: Using the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) we performed multiple old-to-new comparisons of frequently used contemporary knee implants to ask: (1) does overall prosthesis survivorship free from revision increase when a new knee prosthesis system is introduced to replace a prior prosthesis system? (2) Has survivorship free from revision improved for the revision indications of wear, instability, and patellofemoral articulation issues, where development efforts have been concentrated?Methods: Data from the AOANJRR from September 1999 to December 2017 were used to compare the survivorship of prostheses free from revision at a maximum of 17 years in procedures where a new design model was introduced to replace a prior knee system from the same manufacturer. Only prosthesis systems used in a minimum of 2000 primary TKA procedures for osteoarthritis that had a minimum of 5 years of follow-up were included. Varus-valgus constrained and hinge TKA designs were excluded. Cruciate-retaining, posterior-stabilized, and medial pivot-design knees were considered separately. The new and old prosthesis systems were paired for analysis. Survivorship was calculated with Kaplan Meier estimates and comparisons were performed using the Cox proportional hazards method. Subanalyses according to the three main revision indications were performed, and where possible, analyses were performed based on polyethylene types (highly cross-linked polyethylene and ultra-high-molecular-weight polyethylene), combined and separated. Revision was defined as a reoperation of a previous knee arthroplasty in which one or more of the components was removed, replaced, or added. There were 323,955 TKA procedures and 11 new prosthesis system designs that were introduced to replace an earlier knee system from the same manufacturer. Of these prosthesis system pairs, six were cruciate-retaining prostheses, four were posterior-stabilized designs, and one was a medial pivot design.Results: Six of the 11 knee system pairs showed improved survivorship with the new design, three were no different, and in two, the newer prosthesis systems had a higher rate of revision than the old one did. When revision for wear was analyzed, five prosthesis systems showed improvement, five were no different, and one had a higher rate of revision than the previous system did. There was no improvement in the rate of revision for instability; seven new prosthesis systems showed no difference from the previous system and four new prosthesis systems had a higher rate of revision than the previous system did. A subanalysis of revision for patellofemoral complications showed improvement in two comparisons, no difference in six, and a higher revision rate in two; one could not be calculated because of an insufficient number of revisions for this reason.Conclusions: It is difficult to predict whether a new system will demonstrate better survival than a previous one, and widespread uptake of a new design before a benefit is shown in robust clinical studies is unwise. Similarly, adoption of a new system for which there is no difference in survivorship from a previous model may be premature because a new device may have associated unknown and unintended consequences. Healthcare policy makers and therapeutic device regulators should similarly be guided by results and seek out peer-reviewed evidence before accepting change to established practice. Surgeons must be aware that implant changes may not translate into better survivorship and must seek compelling evidence of improvement in survival and/or function before changing systems.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Purpose: Decades of innovations in total knee arthroplasty (TKA) design have led to large number of possible prosthesis combinations in regards fixation, posterior stability, bearing mobility, bearing surface, and patella resurfacing, each of which can alter the revision risk. The accumulative effect when the lowest risk combination in each design category, or "Optimum Prosthesis Combination" (OPC) is utilized remains unknown. The purpose of this analysis was to first, identify the OPC and second, to compare the revision risk of a cohort who received the OPC to a cohort who received an Alternative Prosthesis Combination (APC).Methods: National registry revision risk data for primary TKA for osteoarthritis were obtained from September 1999 to December 2015 for two patient cohorts, those receiving an OPC and those receiving an APC. OPC was defined as TKA with the lowest revision risk option for five primary TKA design categories; fixation, posterior stability, bearing mobility, bearing surface, and patella resurfacing, while APC had one or more higher risk options.Results: Of the 482,373 included TKA, 42,008 (8.7%) were in the OPC cohort, who received a minimally stabilized, fixed bearing TKA with cross-linked polyethylene with patella resurfacing. Both cohorts had similar demographics. At 10 years, the OPC cohort had a Cumulative Percent Revision of 2.4% (95% CI 2.1, 2.8) compared to 5.5% (95% CI 5.4, 5.6) for the APC cohort. For all patients, revision risk of the APC cohort was higher at all times [151% greater at ≥ 3 years (p < 0.001)]. Loosening/lysis was the most common cause of revision in the ACP cohort (1.1%), while it was the second most common cause in the OPC cohort (0.3%). The increased risk was apparent in all age and gender subgroups, with the highest risk increase seen in males ≥ 65 years.Conclusions: Patients receiving the lowest risk prosthesis design combination or Optimum Prosthesis Combination TKA had a 60% lower revision risk, with similar demographics to the Alternative Prosthesis Combination TKA.Level Of Evidence: III. [ABSTRACT FROM AUTHOR]

Background: Periprosthetic infection following total knee replacement remains alarmingly frequent, is devastating for patients, and is an increasingly substantial public health burden. While both the prosthetic design elements and type of polyethylene used in total knee replacement can independently affect survivorship of the prosthesis, their influence on the risk of revision for infection is unknown. Therefore, we examined the effects of total knee prosthetic design and type of polyethylene bearing on the long-term revision risk for nonacute infection following total knee replacement by comparing 4 different cohorts: patients who had minimally stabilized total knee prostheses with crosslinked polyethylene (XLPE) bearing surfaces, minimally stabilized total knee prostheses with noncrosslinked polyethylene (NXLPE), posterior stabilized total knee prostheses with XLPE, and posterior stabilized total knee prostheses with NXLPE.Methods: National registry data on revision procedures for surgeon-reported infection following primary total knee replacement for osteoarthritis from September 1999 through December 2015 were obtained for 4 patient cohorts. The cohorts were defined by the total knee prosthetic design and polyethylene type used. Revisions at ≤6 months were censored to reduce confounding bias. Hazard ratios (HRs) were adjusted for age, sex, and antibiotic cement usage.Results: A total of 336,997 primary total knee prostheses were included, 1,651 (0.49%) of which underwent revision for periprosthetic infection. Compared with minimally stabilized total knee prostheses that had XLPE bearing surfaces, the revision risk for infection, adjusted for age, sex, and antibiotic cement usage, was 25% higher for minimally stabilized total knee prostheses with NXLPE bearing surfaces (HR = 1.25 [95% confidence interval (CI), 1.07 to 1.45]; p = 0.003), 89% higher for posterior stabilized total knee prostheses with XLPE (HR = 1.89 [95% CI, 1.52 to 2.35]; p < 0.001), and 102% higher for posterior stabilized total knee prostheses with NXLPE (HR = 2.02 [95% CI, 1.72 to 2.37]; p < 0.001). Posterior stabilized total knee prostheses with NXLPE had a 61% higher risk of infection compared with minimally stabilized total knee prostheses with NXLPE (HR = 1.61 [95% CI, 1.43 to 1.83]; p < 0.001). The revision risk for infection for posterior stabilized total knee prostheses with NXLPE was the same as that for posterior stabilized total knee prostheses with XLPE (HR = 1.08 [95% CI, 0.88 to 1.32]; p = 0.481).Conclusions: Minimally stabilized total knee prostheses with NXLPE bearing surfaces and posterior stabilized total knee prostheses, irrespective of bearing type, had a greater long-term revision risk for periprosthetic infection when compared with the revision risk for minimally stabilized total knee prostheses with XLPE bearing surfaces.Level Of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of Levels of Evidence. [ABSTRACT FROM AUTHOR]

Background: Some surgeons contend that unicompartmental knee arthroplasty (UKA) can easily be revised to a TKA when revision is called for, whereas others believe that this can be complex and technically demanding. There has been little research regarding the efficacy or rationale of using metal augmentation and tibial stem extensions when revising a UKA to a TKA. QUESTION/PURPOSES: (1) Is the use of stem extensions for the tibial component associated with increased survival when revising a UKA to a TKA? (2) Is the addition of modular augments associated with increased survival compared with stem extensions alone? (3) Is TKA design (minimally stabilized versus posterior-stabilized) or (4) tibial fixation (cemented versus cementless) associated with differences in survivorship?Methods: Data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) were used to analyze implant survival after revision of a UKA to a TKA, comparing results in which tibial components were used with and without modular components. The groups analyzed were TKA without a stem extension, those in which a tibial stem extension was used, and those in which a tibial stem extension was used together with an augment. There were 4438 revisions of UKAs to TKAs available for analysis. The mean duration of followup of patients having the TKA revisions was 5 years (SD, 3.5 years). There were 2901 (65%) procedures in which a tibial stem extension was not used, 870 (20%) procedures with a tibial stem extension, and 667 (15%) with a tibial stem extension and metallic augment. Kaplan-Meier estimates of survivorship were calculated and hazard ratios (HRs) from Cox proportional hazard models, adjusting for age and sex, were used to compare the rate of revision among groups. The overall 10-year cumulative percent revision (CPR) for UKA revised to a TKA was 16%.Results: At 10 years, the CPR was increased when a stem extension was not used (19%; 95% confidence interval [CI],16.5-20.7 without a stem extension compared with 13%; 95% CI, 9.2-17.0 with a stem extension; entire period HR, 1.44; 95% CI, 1.10-1.89; p = 0.007). There was no difference in the 10-year CPR when an augment was used together with a stem extension compared with a stem extension alone (HR, 1.26; 95% CI, 0.85-1.86; p = 0.251). When minimally stabilized and posterior-stabilized TKAs were compared, there was no difference in survivorship. Minimally stabilized TKA designs without stem extensions showed higher CPR compared with when stem extensions were used (HR, 1.77; 95% CI, 1.16-2.70; p = 0.007), whereas posterior-stabilized designs without stem extensions showed higher CPR only when compared with when stem extensions and augments were both used (HR, 2.16; 95% CI, 1.24-3.77; p = 0.006). Cementless fixation of the tibial component resulted in a higher CPR than when cement was used (HR, 1.36; 95% CI 1.08-1.71; p = 0.008).Conclusions: In this registry study, the risk of repeat revision after revision of a UKA to a TKA was lower when a tibial stem extension was used, but no such difference was found with respect to augments. Our study did not account for the degree of bone loss or surgeon preference when considering stems and augments. Further research to establish the degree of bone loss associated with UKA to TKA revision procedures will help clarify these findings.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: The effect of alternative bearing materials on the risk of revision due to infection after total knee replacement remains uncertain. By reducing the immunomodulating polyethylene wear-particle burden and with different substrate bacterial adhesion properties, Oxinium oxidized zirconium and cross-linked polyethylene (XLPE) could alter infection risk. The purpose of the current study was to analyze the risk of revision for infection in 3 comparisons of bearing combinations.Methods: To evaluate the risk of revision for infection with XLPE, cobalt-chromium (CoCr) on XLPE was compared with CoCr on non-cross-linked polyethylene (NXLPE). To evaluate Oxinium, Oxinium-NXLPE was compared with CoCr-NXLPE, and to evaluate the possibility of an additional beneficial effect of Oxinium on XLPE, Oxinium-XLPE was compared with CoCr-XLPE. The cumulative percent revision (CPR) and hazard ratio (HR) for revision for infection in primary total knee replacement for osteoarthritis were determined from registry data from September 1, 1999, to December 31, 2015. Revisions within 6 months following the primary surgery were censored from the analysis, while procedures with posterior stabilized or fully stabilized total knee replacements as well as prostheses with a known higher risk of revision were excluded. Analyses were stratified by age, sex, and fixation type.Results: Of the 326,603 included primary total knee replacements, 1,511 (0.46%) were revised for infection. The risk of revision for infection was lower for CoCr-XLPE compared with CoCr-NXLPE (HR = 0.74; 95% confidence interval [CI] = 0.65 to 0.84; p < 0.001). This effect was apparent for both male and female patients overall, all fixation types, antibiotic cement use, those <65 years of age, and male patients ≥65 years of age. However, for female patients ≥65 years of age, there was no difference. Overall, Oxinium-NXLPE had the same revision risk as CoCr-NXLPE regardless of fixation; however, for cemented fixation, subanalysis showed a lower risk for Oxinium-NXLPE compared with CoCr-NXLPE (HR = 0.69; 95% CI = 0.51 to 0.94; p = 0.018). Oxinium-XLPE had the same revision risk for infection as CoCr-XLPE overall, among male patients, and when cemented fixation had been used.Conclusions: In this registry analysis, CoCr-XLPE had a 26% lower risk of revision for infection than CoCr-NXLPE, suggesting a reduction of wear particle-induced immunomodulation with XLPE. Oxinium-XLPE had the same risk as CoCr-XLPE. Overall, Oxinium did not reduce the infection risk.Level Of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Earlier results with porous tantalum acetabular cups in revision THA generally have been favorable. Recently there has been some evidence presented that porous tantalum cups might decrease the risk of rerevision in the setting of revision hip surgery performed owing to prosthetic joint infection (PJI). As the data supporting this assertion come from a study with a limited study population, examining this issue with a large registry approach may be enlightening.Questions/purposes: By combining results from two large, national registries, we asked: (1) Do porous tantalum cups show improved survival after revision THA compared with other cementless designs? (2) Does the use of porous tantalum cups influence survivorship when rerevision for PJI is the endpoint?Methods: A total of 2442 first-time THA revisions with porous tantalum cups and 4401 first-time revisions with other uncemented cups were included in this collaborative study between the Australian and Swedish national joint registries. The mean age of the patients was 69 years (range, 19-97 years), 3754 (55%) of the patients were women, and the mean followup for the porous tantalum and uncemented control groups were 3.0 years (SD, ± 2.1 years) and 3.4 years (SD, ± 2.3 years), respectively. Concomitant stem revision was more common in the porous tantalum group (43% versus 36%). The use of porous tantalum augments also was analyzed as a proxy for more complex acetabular reconstructions. In an attempt to further reduce selection bias, we performed subgroup analysis for primary operations attributable to osteoarthritis and first revision attributable to aseptic loosening.Results: Kaplan-Meier survivorship with rerevisison for any reason up to 7 years was comparable between the porous tantalum cup group and the uncemented cup control group (86% [95% CI, 85%-89%] and 87% [95% CI, 85%-89%], respectively; p = 0.85) and the overall survivorship up to 7 years with a second revision for PJI as the endpoint (97% [95% CI, 95%-98%] and 97% [95% CI, 96%-98%], respectively; p = 0.64). Excluding procedures where augments had been used or studying primary osteoarthritis and first revision owing to aseptic loosening subgroups did not change this result.Conclusions: Implant survival for a porous tantalum cup in first-time THA revision was similar to the survival of the uncemented cup control group. With the numbers available, no benefit in survival with rerevision for infection as the endpoint could be ascribed to the porous tantalum cup group, as has been suggested by earlier work. Further studies with acetabular bone deficiency data, greater insight into host comorbidity factors, and a longer followup are needed to corroborate or refute these results.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background and purpose —While highly crosslinked polyethylene has shown reduced in vivo wear and lower rates of revision for total hip arthroplasty, there have been few long-term studies on its use in total knee arthroplasty (TKA). We compared the rate of revision of non-crosslinked polyethylene to that of crosslinked polyethylene in patients who underwent TKA for osteoarthritis. Patients and methods —We examined data from the Australian Orthopaedic Association National Joint Replacement Registry on 302,214 primary TKA procedures with non-crosslinked polyethylene and 83,890 procedures with crosslinked polyethylene, all of which were performed for osteoarthritis. The survivorship of the different polyethylenes was estimated using the Kaplan-Meier method and was compared using proportional hazard models. Results —The 10-year cumulative revision rate for non-crosslinked polyethylene was 5.8% (95% CI: 5.7–6.0) and for crosslinked polyethylene it was 3.5% (95% CI: 3.2–3.8) (> 6.5-year HR = 2.2 (1.5–3.1); p < 0.001). There was no effect of surgical volume or method of prosthesis fixation on outcome. There were 4 different TKA designs that had a minimum of 2,500 procedures in at least 1 of the polyethylene groups and a follow-up of ≥ 5 years. 2 of these, the NexGen and the Natural Knee II, had a lower rate of revision for crosslinked polyethylene. The Scorpio NRG/Series 7000 and the Triathlon Knee did not show a lower rate of revision for crosslinked polyethylene. Interpretation —There is a lower rate of revision for crosslinked polyethylene in TKA, and this appears to be prosthesis-specific and when it occurs is most evident in patients < 65 years of age. The difference in revision rates was mainly due to revisions because of lysis and loosening. [ABSTRACT FROM PUBLISHER]

Background: Articular Surface Replacement (ASR) hip prostheses, which have metal-on-metal bearing surfaces, were manufactured by DePuy Orthopaedics (Warsaw, Indiana) for use in both conventional total hip arthroplasty and hip resurfacing. Both the ASR XL Acetabular System and the ASR Hip Resurfacing System were recently recalled worldwide by the manufacturer. This report summarizes an analysis by the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) of the outcome of arthroplasties involving the ASR prostheses. Methods: The first recorded use of the ASR XL Acetabular System in Australia occurred in 2004, and the Registry recorded 4406 procedures involving this system through December 31, 2009. The first recorded use of the ASR Hip Resurfacing System in Australia occurred in 2003, and the Registry recorded 1167 procedures through December 31, 2009. The Kaplan-Meier method and proportional-hazard modeling were used to compare the revision rate of primary total hip arthroplasties involving the ASR XL Acetabular System with that of arthroplasties involving all other conventional prostheses as well as with that of arthroplasties involving all other conventional prostheses with a metal-on-metal-articulation. In addition, the revision rate of primary arthroplasties involving the ASR Hip Resurfacing System was compared with that of arthroplasties involving all other hip resurfacing prostheses. Patient demographics, prosthesis characteristics, and information regarding the type of revision and the reason for revision were also compared. Results: Arthroplasties involving both ASR designs had a significantly greater revision rate compared with those involving all other prostheses. The cumulative revision rate of arthroplasties involving the ASR XL Acetabular System at five years postoperatively was 9.3% (95% confidence interval [CI], 7.3% to 11.9%) compared with 3.4% (95% CI, 3.3% to 3.5%) for total hip arthroplasties involving all other conventional prostheses. The cumulative revision rate of arthroplasties involving the ASR Hip Resurfacing System at five years postoperatively was 10.9% (95% CI, 8.7% to 13.6%) compared with 4.0% (95% Cl, 3.7% to 4.5%) for arthroplasties involving all other resurfacing prostheses. Arthroplasties involving the ASR XL Acetabular System had a greater rate of revision due to implant loosening and/or osteolysis and due to metal sensitivity compared with total hip arthroplasties involving all other conventional prostheses. Arthroplasties involving the ASR XL Acetabular System also had a significantly greater revision rate compared with total hip arthroplasties involving all other conventional metal-on-metal prostheses. Arthroplasties involving the ASR Hip Resurfacing System had a greater rate of revision due to metal sensitivity compared with total hip arthroplasties involving all other resurfacing prostheses. Conclusions: ASR prostheses used in conventional hip arthroplasty and in hip resurfacing exhibited a greater revision rate compared with other prostheses in the AOANJRR. These results are consistent with those derived from other registries and from published studies of individual cohorts. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Purpose Here we describe some available statistical models and illustrate their use for analysis of arthroplasty registry data in the presence of the competing risk of death, when the influence of covariates on the revision rate may be different to the influence on the probability (that is, risk) of the occurrence of revision. Patients and methods Records of 12,525 patients aged 75-84 years who had received hemiarthroplasty for fractured neck of femur were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. The covariates whose effects we investigated were: age, sex, type of prosthesis, and type of fixation (cementless or cemented). Extensions of competing risk regression models were implemented, allowing the effects of some covariates to vary with time. Results The revision rate was significantly higher for patients with unipolar than bipolar prostheses (HR == 1.38, 95% CI: 1.01-1.89) or with monoblock than bipolar prostheses (HR == 1.45, 95% CI: 1.08-1.94). It was significantly higher for the younger age group (75-79 years) than for the older one (80-84 years) (HR == 1.28, 95% CI: 1.05-1.56) and higher for males than for females (HR == 1.37, 95% CI: 1.09-1.71). The probability of revision, after correction for the competing risk of death, was only significantly higher for unipolar prostheses than for bipolar prostheses, and higher for the younger age group. The effect of fixation type varied with time; initially, there was a higher probability of revision for cementless prostheses than for cemented prostheses, which disappeared after approximately 1.5 years. Interpretation When accounting for the competing risk of death, the covariates type of prosthesis and sex influenced the rate of revision differently to the probability of revision. We advocate the use of appropriate analysis tools in the presence of competing risks and when covariates have time-dependent effects. [ABSTRACT FROM AUTHOR]

Background and purpose The Kaplan-Meier (KM) method is often used in the analysis of arthroplasty registry data to estimate the probability of revision after a primary procedure. In the presence of a competing risk such as death, KM is known to overestimate the probability of revision. We investigated the degree to which the risk of revision is overestimated in registry data. Patients and methods We compared KM estimates of risk of revision with the cumulative incidence function (CIF), which takes account of death as a competing risk. We considered revision by (1) prosthesis type in subjects aged 75-84 years with fractured neck of femur (FNOF), (2) cement use in monoblock prostheses for FNOF, and (3) age group in patients undergoing total hip arthroplasty (THA) for osteoarthritis (OA). Results In 5,802 subjects aged 75-84 years with a monoblock prosthesis for FNOF, the estimated risk of revision at 5 years was 6.3% by KM and 4.3% by CIF, a relative difference (RD) of 46%. In 9,821 subjects of all ages receiving an Austin Moore (non-cemented) prosthesis for FNOF, the RD at 5 years was 52% and for 3,116 subjects with a Thompson (cemented) prosthesis, the RD was 79%. In 44,365 subjects with a THA for OA who were less than 70 years old, the RD was just 1.4%; for 47,430 subjects > 70 years of age, the RD was 4.6% at 5 years. Interpretation The Kaplan-Meier method substantially overestimated the risk of revision compared to estimates using competing risk methods when the risk of death was high. The bias increased with time as the incidence of the competing risk of death increased. Registries should adopt methods of analysis appropriate to the nature of their data. [ABSTRACT FROM AUTHOR]