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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]

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: 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: Joint arthroplasty registries traditionally report survivorship outcomes mainly on primary joint arthroplasty. The outcome of first revision procedures is less commonly reported, because large numbers of primary procedures are required to analyze a sufficient number of first revision procedures. Additionally, adequate linkage of primary procedures to revisions and mortality is required. When undertaking revision hip surgery, it is important for surgeons to understand the outcomes of these procedures to better inform patients.Questions/purposes: Using data from a large national joint registry, we asked: (1) What is the overall rate of revision of the first aseptic revision procedure for a primary THA? (2) Does the rate of revision of the first revision vary by the diagnosis for the first revision? (3) What is the mortality after the first revision, and does it vary by the reason for first revision?Methods: The Australian Orthopaedic Association National Joint Replacement Registry longitudinally maintains data on all primary and revision joint arthroplasties, with nearly 100% capture. The analyses for this study were performed on primary THA procedures in patients with a diagnosis of osteoarthritis up to December 31, 2020, who had undergone subsequent revision. We excluded all primary THAs involving metal-on-metal and ceramic-on-metal bearing surfaces and prostheses with exchangeable necks because these designs may have particular issues associated with revisions, such as extensive soft tissue destruction, that are not seen with conventional bearings, making a comparative analysis of the first revision involving these bearing surfaces more complicated. Metal-on-metal bearing surfaces have not been used in Australia since 2017. We identified 17,046 first revision procedures from the above study population and after exclusions, included 13,713 first revision procedures in the analyses. The mean age at the first revision was 71 ± 11 years, and 55% (7496 of 13,713) of the patients were women. The median (IQR) time from the primary procedure to the first revision was 3 years (0.3 to 7.3), ranging from 0.8 years for the diagnosis of dislocation and instability to 10 years for osteolysis. There was some variation depending on the reason for the first revision. For example, patients undergoing revision for fracture were slightly older (mean age 76 ± 11 years) and patients undergoing revision for dislocation were more likely to be women (61% [2213 of 3620]). The registry has endeavored to standardize the sequence of revisions and uses a numerical approach to describe revision procedures. The first revision is the revision of a primary procedure, the second revision is the revision of the first revision, and so on. We therefore described the outcome of the first revision as the cumulative percent second revision. The outcome measure was the cumulative percent revision, which was defined using Kaplan-Meier estimates of survivorship to describe the time to the second revision. Hazard ratios from Cox proportional hazards models, adjusting for age and gender, were performed to compare the revision rates among groups. When possible, the cumulative percent second revision at the longest follow-up timepoint was determined with the available data, and when there were insufficient numbers, we used appropriate earlier time periods.Results: The cumulative percent second revision at 18 years was 26% (95% confidence interval [CI] 24% to 28%). When comparing the outcome of the first revision by reason, prosthesis dislocation or instability had the highest rate of second revision compared with the other reasons for first revision. Dual-mobility prostheses had a lower rate of second revision for dislocation or instability than head sizes 32 mm or smaller and when compared to constrained prostheses after 3 months. There was no difference between dual-mobility prostheses and head sizes larger than 32 mm. There were no differences in the rate of second revision when first revisions for loosening, periprosthetic fracture, and osteolysis were compared. If cemented femoral fixation was performed at the time of the first revision, there was a higher cumulative percent second revision for loosening than cementless fixation from 6 months to 6 years, and after this time, there was no difference. The overall mortality after a first revision of primary conventional THA was 1% at 30 days, 2% at 90 days, 5% at 1 year, and 40% at 10 years. A first revision for periprosthetic fracture had the highest mortality at all timepoints compared with other reasons for the first revision.Conclusion: Larger head sizes and dual-mobility cups may help reduce further revisions for dislocation, and the use of cementless stems for a first revision for loosening seems advantageous. Surgeons may counsel patients about the higher risk of death after first revision procedures, particularly if the first revision is performed for periprosthetic fracture.Level of Evidence Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Loss of glenoid fixation is a key factor affecting the survivorship of primary total shoulder arthroplasty (TSA). It is not known whether the lower revision rates associated with crosslinked polyethylene (XLPE) compared with those of non-XLPE identified in hip and knee arthroplasty apply to shoulder arthroplasty.Questions/purposes: We used data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) to compare the revision rates of primary stemmed anatomic TSA using XLPE to procedures using non-XLPE. In patients receiving a primary stemmed anatomic TSA for osteoarthritis, we asked: (1) Does the rate of revision or reason for revision vary between XLPE and non-XLPE all-polyethylene glenoid components? (2) Is there any difference in the revision rate when XLPE is compared with non-XLPE across varying head sizes? (3) Is there any difference in survival among prosthesis combinations with all-polyethylene glenoid components when they are used with XLPE compared with non-XLPE?Methods: Data were extracted from the AOANJRR from April 16, 2004, to December 31, 2020. The AOANJRR collects data on more than 97% of joint replacements performed in Australia. The study population included all primary, stemmed, anatomic TSA procedures performed for osteoarthritis using all-polyethylene glenoid components. Procedures were grouped into XLPE and non-XLPE bearing surfaces for comparison. Of the 10,102 primary stemmed anatomic TSAs in the analysis, 39% (3942 of 10,102) used XLPE and 61% (6160 of 10,102) used non-XLPE. There were no differences in age, gender, or follow-up between groups. 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. Revision was defined as removal, replacement, or addition of any component of a joint replacement. The unadjusted cumulative percent revision after the primary arthroplasty (with 95% confidence intervals [CIs]) was calculated and compared using Cox proportional hazard models adjusted for age, gender, fixation, and surgeon volume. Further analyses were performed stratifying according to humeral head size, and a prosthesis-specific analysis adjusted for age and gender was also performed. This analysis was restricted to prosthesis combinations that were used at least 150 times, accounted for at least four revisions, had XLPE and non-XLPE options available, and had a minimum of 3 years of follow-up.Results: Non - XLPE had a higher risk of revision than XLPE after 1.5 years (HR 2.3 [95% CI 1.6 to 3.1]; p < 0.001). The cumulative percent revision at 12 years was 5% (95% CI 4% to 6%) for XLPE and 9% (95% CI 8% to 10%) for non-XLPE. There was no difference in the rate of revision for head sizes smaller than 44 mm. Non-XLPE had a higher rate of revision than XLPE for head sizes 44 to 50 mm after 2 years (HR 2.3 [95% CI 1.5 to 3.6]; p < 0.001) and for heads larger than 50 mm for the entire period (HR 2.2 [95% CI 1.4 to 3.6]; p < 0.001). Two prosthesis combinations fulfilled the inclusion criteria for the prosthesis-specific analysis. One had a higher risk of revision when used with non-XLPE compared with XLPE after 1.5 years (HR 3.7 [95% CI 2.2 to 6.3]; p < 0.001). For the second prosthesis combination, no difference was found in the rate of revision between the two groups.Conclusion: These AOANJRR data demonstrate that noncrosslinked, all-polyethylene glenoid components have a higher revision rate compared with crosslinked, all-polyethylene glenoid components when used in stemmed anatomic TSA for osteoarthritis. As polyethylene type is likely an important determinant of revision risk, crosslinked polyethylene should be used when available, particularly for head sizes larger than 44 mm. Further studies will need to be undertaken after larger numbers of shoulder arthroplasties have been performed to determine whether this reduction in revision risk associated with XLPE bears true for all TSA designs.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: The ability to identify which patients are at a greater risk of early revision knee arthroplasty has important practical and resource implications. Many international arthroplasty registries administer patient-reported outcome measures (PROMs) to provide a holistic assessment of pain, function, and quality of life. However, few PROM scores have been evaluated as potential indicators of early revision knee arthroplasty, and earlier studies have largely focused on knee-specific measures.Questions/purposes: This national registry-based study asked: (1) Which 6-month postoperative knee-specific and generic PROM scores are associated with early revision knee arthroplasty (defined as revision surgery performed 6 to 24 months after the primary procedure)? (2) Is a clinically important improvement in PROM scores (based on thresholds for the minimal important change) after primary knee arthroplasty associated with a lower risk of early revision?Methods: Preoperative and 6-month postoperative PROM scores for patients undergoing primary knee arthroplasty were sourced from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and Arthroplasty Clinical Outcomes Registry National. Between January 2013 and December 2020, PROM data were available for 19,402 primary total knee arthroplasties; these data were linked to AOANJRR data on revision knee arthroplasty. Of these, 3448 procedures were excluded because they did not have 6-month PROM data, they had not reached the 6-month postoperative point, they had died before 24 months, or they had received revision knee arthroplasty before the 6-month PROMs assessment. After these exclusions, data were analyzed for 15,954 primary knee arthroplasties. Associations between knee-specific (knee pain, Oxford Knee Score, and 12-item Knee injury and Osteoarthritis Outcome Score [KOOS-12]) or generic PROM scores (5-level EuroQol quality of life instrument [EQ-5D], EQ VAS, perceived change, and satisfaction) and revision surgery were explored using t-tests, chi-square tests, and regression models. Ninety-four revision procedures were performed at 6 to 24 months, most commonly for infection (39% [37 procedures]). The early revision group was younger than the unrevised group (mean age 64 years versus 68 years) and a between-group difference in American Society of Anesthesiologists (ASA) grade was noted. Apart from a small difference in preoperative low back pain for the early revision group (mean low back pain VAS 4.2 points for the early revision group versus 3.3 points for the unrevised group), there were no between-group differences in preoperative knee-specific or generic PROM scores on univariate analysis. As the inclusion of ASA grade or low back pain score did not alter the model results, the final multivariable model included only the most clinically plausible confounders (age and gender) as covariates. Multivariable models (adjusting for age and gender) were also used to examine the association between a clinically important improvement in PROM scores (based on published thresholds for minimal important change) and the likelihood of early revision.Results: After adjusting for age and gender, poor postoperative knee pain, Oxford, KOOS-12, EQ-5D, and EQ VAS scores were all associated with early revision. A one-unit increase (worsening) in knee pain at 6 months was associated with a 31% increase in the likelihood of revision (RR 1.31 [95% confidence interval (CI) 1.19 to 1.43]; p < 0.001). Reflecting the reversed scoring direction, a one-unit increase (improvement) in Oxford or KOOS-12 score was associated with a 9% and 5% reduction in revision risk, respectively (RR for Oxford: 0.91 [95% CI 0.90 to 0.93]; p < 0.001; RR for KOOS-12 summary: 0.95 [95% CI 0.94 to 0.97]; p < 0.001). Patient dissatisfaction (RR 6.8 [95% CI 3.7 to 12.3]) and patient-perceived worsening (RR 11.7 [95% CI 7.4 to 18.5]) at 6 months were also associated with an increased likelihood of early revision. After adjusting for age and gender, patients who did not achieve a clinically important improvement in PROM scores had a higher risk of early revision (RR 2.9 for the knee pain VAS, RR 4.2 for the Oxford Knee Score, RR 6.3 to 8.6 for KOOS-12, and RR 2.3 for EQ-5D) compared with those who did (reference group).Conclusion: Knee-specific and generic PROM scores offer an efficient approach to identifying patients at greater risk of early revision surgery, using either the 6-month score or the magnitude of improvement. These data indicate that surgeons can use single- and multi-item measures to detect a patient-perceived unsuccessful surgical outcome at 6 months after primary knee arthroplasty. Surgeons should be alert to poor PROM scores at 6 months or small improvements in scores (for example, less than 2 points for knee pain VAS or less than 10.5 points for Oxford Knee Score), which signal a need for direct patient follow-up or expedited clinical review.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: When arthroplasty is indicated for a femoral neck fracture (FNF), it is unclear whether total hip arthroplasty (THA) or hemiarthroplasty (HA) is best. This study compares data from the Australian Orthopaedic Association National Joint Replacement Registry using contemporary surgical options.Methods: Patients from 60 to 85 years old who were treated with arthroplasty for FNF, between September 1999 and December 2019, were included if the femoral stems were cemented. Only THAs with femoral heads of ≥36 mm or dual-mobility articulations were included. Patients who had monoblock HA were excluded. Rates of revision for all aseptic failures and dislocation were compared. Competing risks of revision and death were considered using the cumulative incidence function. Subdistribution hazard ratios (HRs) for revision or death from a Fine-Gray regression model were used to compare THA and HA. Interactions of procedure with age group and sex were considered. Secondary analysis adjusting for body mass index (BMI) and American Society of Anesthesiologists (ASA) classification was also considered.Results: There were 4,551 THA and 29,714 HA procedures included. The rate of revision for THA was lower for women from 60 to 69 years old (HR = 0.58 [95% confidence interval (CI), 0.39 to 0.85]) and from 70 to 74 years old (HR = 0.65 [95% CI, 0.43 to 0.98]) compared with HA. However, women from 80 to 85 years old (HR = 1.56 [95% CI, 1.03 to 2.35]) and men from 75 to 79 years old (HR = 1.61 [95% CI, 1.05 to 2.46]) and 80 to 85 years old (HR = 2.73 [95% CI, 1.89 to 3.95]) had an increased rate of revision when THA was undertaken compared with HA. There was no difference in the rate of revision for dislocation between THA and HA for either sex or age categories.Conclusions: When contemporary surgical options for FNF are used, there is a benefit with respect to revision outcomes for THA in women who are <75 years old and a benefit for HA in women who are ≥80 years old and men who are ≥75 years old. There is no difference in dislocation rates.Level Of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Dislocation is one of the most common causes of a re-revision after a revision THA. Dual-mobility constructs and large femoral head bearings (≥ 36 mm) are known options for mitigating this risk. However, it is unknown which of these choices is better for reducing the risk of dislocation and all-cause re-revision surgery. It is also unknown whether there is a difference between dual-mobility constructs and large femoral head bearings according to the size of the acetabular component.Questions/purposes: We used data from a large national registry to ask: In patients undergoing revision THA for aseptic causes after a primary THA performed for osteoarthritis, (1) Does the proportion of re-revision surgery for prosthesis dislocation differ between revision THAs performed with dual-mobility constructs and those performed with large femoral head bearings? (2) Does the proportion of re-revision surgery for all aseptic causes differ between revision THAs performed with dual-mobility constructs and those performed with large femoral head bearings? (3) Is there a difference when the results are stratified by acetabular component size?Methods: Data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) were analyzed for 1295 first-revision THAs for aseptic causes after a primary THA performed for osteoarthritis. The study period was from January 2008-when the first dual-mobility prosthesis was recorded-to December 2019. There were 502 dual-mobility constructs and 793 large femoral head bearings. There was a larger percentage of women in the dual-mobility construct group (67% [334 of 502]) compared with the large femoral head bearing group (51% [402 of 793]), but this was adjusted for in the statistical analysis. Patient ages were similar for the dual-mobility construct group (67 ± 11 years) and the large femoral head group (65 ± 12 years). American Society of Anesthesiologists (ASA) class and BMI distributions were similar. The mean follow-up was shorter for dual-mobility constructs at 2 ± 1.8 years compared with 4 ± 2.9 years for large femoral head bearings. The cumulative percent revision (CPR) was determined for a diagnosis of prosthesis dislocation as well as for all aseptic causes (excluding infection). Procedures using metal-on-metal bearings were excluded. The time to the re-revision was described using Kaplan-Meier estimates of survivorship, with right censoring for death or database closure at the time of analysis. The unadjusted CPR was estimated each year of the first 5 years for dual-mobility constructs and for each of the first 9 years for large femoral head bearings, with 95% confidence intervals using unadjusted pointwise Greenwood estimates. The apparent shorter follow-up of the dual-mobility construct group relates to the more recent increase in dual-mobility numbers recorded in the registry. The results were adjusted for age, gender, and femoral fixation. Results were subanalyzed for acetabular component sizes < 58 mm and ≥ 58 mm, set a priori on the basis of biomechanical and other registry data.Results: There was no difference in the proportion of re-revision for prosthesis dislocation between dual-mobility constructs and large femoral head bearings (hazard ratio 1.22 [95% CI 0.70 to 2.12]; p = 0.49). At 5 years, the CPR of the re-revision for prosthesis dislocation was 4.0% for dual mobility constructs (95% CI 2.3% to 6.8%) and 4.1% for large femoral head bearings (95% CI 2.7% to 6.1%). There was no difference in the proportion of all aseptic-cause second revisions between dual-mobility constructs and large femoral head bearings (HR 1.02 [95% CI 0.76 to 1.37]; p = 0.89). At 5 years, the CPR of dual-mobility constructs was 17.6% for all aseptic-cause second revision (95% CI 12.6% to 24.3%) and 17.8% for large femoral head bearings (95% CI 14.9% to 21.2%). When stratified by acetabular component sizes less than 58 mm and at least 58 mm, there was no difference in the re-revision CPR for dislocation or for all aseptic causes between dual-mobility constructs and large femoral head bearings.Conclusion: Either dual-mobility constructs or large femoral head bearings can be used in revision THA, regardless of acetabular component size, as they did not differ in terms of re-revision rates for dislocation and all aseptic causes in this registry study. Longer term follow-up is required to assess whether complications develop with either implant or whether a difference in revision rates becomes apparent. Ongoing follow-up and comparison in a registry format would seem the best way to compare long-term complications and revision rates. Future studies should also compare surgeon factors and whether they influence decision-making between prosthesis options and second revision rates. Nested randomized controlled trials in national registries would seem a viable option for future research.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Long-term implant survivorship in THA and TKA involves a combination of factors related to the patient, the implants used, and the decision-making and technical performance of the surgeon. It is unclear which of these factors is the most important in reducing the proportion of revision surgery.Questions/purposes: We used data from a large national registry to ask: In patients receiving primary THA and TKA for a diagnosis of osteoarthritis, do (1) the reasons for revision and (2) patient factors, the implants used, and the surgeon or surgical factors differ between surgeons performing THA and TKA who have a lower revision rate compared with all other surgeons?Methods: Data were analyzed for all THA and TKA procedures performed for a diagnosis of osteoarthritis from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from September 1, 1999, when collection began, to December 31, 2018. The AOANJRR obtains data on more than 98% of joint arthroplasties performed in Australia. The 5-year cumulative percent revision (CPR) was identified for all THAs and TKAs performed for a diagnosis of osteoarthritis with 95% confidence intervals (overall CPR); the 5-year CPR with 95% CIs for each surgeon was calculated for THA and TKA separately. For surgeons to be included in the analysis, they had to have performed at least 50 procedures and have a 5-year CPR. The 5-year CPR with 95% CIs for each THA and TKA surgeon was compared with the overall CPR. Two groups were defined: low revision rate surgeons (the upper confidence level for a given surgeon at 5 years is less than 3.84% for THA and 4.32% for TKA), and all other surgeons (any surgeon whose CPR was higher than those thresholds). The thresholds were determined by setting a cutoff at 20% above the upper confidence level for that class. The approach we used to define a low revision rate surgeon was similar to that used by the AOANJRR for determining the better-performing prostheses and is recommended by the International Prosthesis Benchmarking Working Group. By defining the groups in this way, a significant difference between these two groups is created. Determining a reason for this difference is the purpose of presenting the proportions of different factors within each group. The study group for THA included 116 low revision rate surgeons, who performed 88,392 procedures (1619 revised, 10-year CPR 2.7% [95% CI 2.6% to 2.9%]) and 433 other surgeons, who performed 170,094 procedures (6911 revised, 10-year CPR 5.9% [95% CI 5.7% to 6.0%]). The study group for TKA consisted of 144 low revision rate surgeons, who performed 159,961 procedures (2722 revised, 10-year CPR 2.6% [95% CI 2.5% to 2.8%]) and 534 other surgeons, who performed 287,232 procedures (12,617 revised, 10-year CPR 6.4% [95% CI 6.3% to 6.6%]). These groups were defined a priori by their rate of revision, and the purpose of this study was to explore potential reasons for this observed difference.Results: For THA, the difference in overall revision rate between low revision rate surgeons and other surgeons was driven mainly by fewer revisions for dislocation, followed by component loosening and fracture in patients treated by low revision rate surgeons. For TKA, the difference in overall revision rate between low revision rate surgeons and other surgeons was driven mainly by fewer revisions for aseptic loosening, followed by instability and patellofemoral complications in patients treated by low revision rate surgeons. Patient-related factors were generally similar between low revision rate surgeons and other surgeons for both THA and TKA. Regarding THA, there were differences in implant factors, with low revision rate surgeons using fewer types of implants that have been identified as having a higher-than-anticipated rate of revision within the AOANJRR. Low revision rate surgeons used a higher proportion of hybrid fixation, although cementless fixation remained the most common choice. For surgeon factors, low revision rate surgeons were more likely to perform more than 100 THA procedures per year, while other surgeons were more likely to perform fewer than 50 THA procedures per year. In general, the groups of surgeons (low revision rate surgeons and other surgeons) differed less in terms of years of surgical experience than they did in terms of the number of cases they performed each year, although low revision rate surgeons, on average, had more years of experience and performed more cases per year. Regarding TKA, there were more differences in implant factors than with THA, with low revision rate surgeons more frequently performing patellar resurfacing, using an AOANJRR-identified best-performing prosthesis combination (with the lowest rates of revision), using fewer implants that have been identified as having a higher-than-anticipated rate of revision within the AOANJRR, using highly crosslinked polyethylene, and using a higher proportion of cemented fixation compared with other surgeons. For surgeon factors, low revision rate surgeons were more likely to perform more than 100 TKA procedures per year, whereas all other surgeons were more likely to perform fewer than 50 procedures per year. Again, generally, the groups of surgeons (low revision rate surgeons and other surgeons) differed less in terms of years of surgical experience than they did in terms of the number of cases they performed annually, although low revision rate surgeons, on average, had more years of experience and performed more cases per year.Conclusion: THAs and TKAs performed by surgeons with the lowest revision rates in Australia show reductions in all of the leading causes of revision for both THA and TKA, in particular, causes of revision related to the technical performance of these procedures. Patient factors were similar between low revision rate surgeons and all other surgeons for both THA and TKA. Low revision rate THA surgeons were more likely to use cement fixation selectively. Low revision rate TKA surgeons were more likely to use patella resurfacing, crosslinked polyethylene, and cemented fixation. Low revision rate THA and TKA surgeons were more likely to use an AOANJRR-identified best-performing prosthesis combination and to use fewer implants identified by the AOANJRR as having a higher-than-anticipated revision rate. To reduce the rate of revision THA and TKA, surgeons should consider addressing modifiable factors related to implant selection. Future research should identify surgeon factors beyond annual case volume that are important to improving implant survivorship.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: 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: Despite wide adoption of hydroxyapatite (HA)-coated femoral stems in THA, no studies have found differences in the risk of revision surgery with its use or investigated the interaction of different prosthesis designs with stem coating.Questions/purposes: The purpose of this study was to evaluate the risk of revision in THAs with HA-coated stems compared with non-HA-coated. To achieve this purpose, we asked: (1) What is the difference in risk of revision of THAs with HA-coated femoral stems compared with non-HA-coated using an aggregate analysis? (2) What is the difference in risk of revision of THAs with HA-coated femoral stems compared with non-HA-coated for five prosthesis types that used the same femoral and acetabular component combination but where the femoral stem had both a HA and non-HA coating option?Methods: The Australian Orthopaedic Association National Joint Replacement Registry analyzed cementless primary THA registered between September 1, 1999, and December 31, 2014. Of the 147,645 cases that fit our selection criteria, 81.1% (N = 119,673) had HA-coated stems. Overall (that is, all procedures with any prostheses in the registry) and five prosthesis designs where both an HA-coated stem and non-HA-coated stem exist (Zimmer's VerSys®/Trilogy® [N = 3924], Biomet's Mallory-Head®/Mallory-Head [N = 2538], Smith & Nephew's SL-Plus/EP Fit-Plus [N = 2028], Biomet's Taperloc®/Exceed [N = 1668], and Biomet's Taperloc/Mallory-Head [N = 1240]) were evaluated. Revision surgery was the outcome of interest. Survival analyses were conducted and hazard ratios (HRs) were adjusted for age, sex, bearing surface, femoral head size, and acetabular component HA coating.Results: In the overall cohort, HA stems had a lower any-cause revision risk after 6 months (HR, 0.83; 95% confidence interval [CI], 0.72-0.95; p = 0.007). However, the risk of revision varied when we evaluated the effect of HA on revision for specific prothesis combinations that had both HA and non-HA options for the femoral stem. VerSys/Trilogy, Mallory-Head/Mallory-Head, Taperloc/Exceed, and Taperloc/Mallory-Head did not have a lower risk of any-cause revision with HA-coated stems compared with non-HA-coated. Only the SL-Plus/EP Fit-Plus subgroup showed a lower risk of revision for loosening (HR, 0.17; 95% CI, 0.06-0.44 between 0 and 7 years; p < 0.001) with HA- compared with non-HA-coated stems, but this was observed after an early (< 6 months) higher risk of revision for any reason (HR, 2.88; 95% CI, 1.15-7.21; p = 0.024).Conclusions: Overall, HA coating of femoral stems was found to be associated with a 17% lower risk of revision for any reason. However, the lower risk of revision associated with HA was not consistent for all prosthesis designs where both HA- and non-HA-coated femoral stem versions were available. Some HA-coated stems have higher revision rates compared with their non-HA-coated versions. Our findings suggest that the effect of HA coating on revision risk varies depending on prosthesis design.Level Of Evidence: Level II, 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: 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]