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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: Obesity is associated with the development of knee osteoarthritis (OA). The aim of this study was to examine the incidence of obesity in patients undergoing knee replacement (KR) for OA in Australia compared to the incidence of obesity in the general population. Methods: A cohort study was conducted, comparing data from the Australian Bureau of Statistics (ABS) 2017–2018 National Health Survey with data from the National Joint Replacement Registry. The distribution of patients who underwent KR from July 2017 to June 2018 by BMI category was compared to the distribution of the general population, in age and gender sub‐groups. Results: During the study period, 35.6% of Australian adults were overweight and 31.3% were obese. Of the 56 217 patients who underwent primary KR for OA, 31.9% were overweight and 57.7% were obese. The relative risk of undergoing KR for OA increased with increasing BMI category. Class 1, 2 and 3 obese females aged 55–64 years were 4.7, 8.4 and 17.3 times more likely to undergo KR than their normal weight counterparts, respectively. Males in the same age and BMI categories were 3.4, 4.5 and 5.8 times more likely to undergo KR, respectively. Class 3 obese patients underwent KR 7 years younger, on average, than normal weight individuals. Conclusion: Obesity is associated with an increased risk of undergoing KR, and at a younger age, particularly for females. There is an urgent need for a societal level approach to address the prevalence of obesity, to reduce the burden of obesity related KR. [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: Computer navigation for total knee arthroplasty has improved alignment compared with that resulting from non-navigated total knee arthroplasty. This study analyzed data from the Australian Orthopaedic Association National Joint Replacement Registry to examine the effect of computer navigation on the rate of revision of primary total knee arthroplasty. Methods: The cumulative percent revision following all non-navigated and navigated primary total knee arthroplasties performed in Australia from January 1, 2003, to December 31, 2012, was assessed. In addition, the type of and reason for revision as well as the effect of age, surgeon volume, and use of cement for the prosthesis were examined. Kaplan- Meier estimates of survivorship were used to describe the time to first revision. Hazard ratios (HRs) from Cox proportional hazards models, with adjustment for age and sex, were used to compare revision rates. Results: Computer navigation was used in 44,573 (14.1% of all) primary total knee arthroplasties, and the rate of its use increased from 2.4% in 2003 to 22.8% in 2012. Overall, the cumulative percent revision following non-navigated total knee arthroplasty at nine years was 5.2% (95% confidence interval [CI] = 5.1 to 5.4) compared with 4.6% (95% CI = 4.2 to 5.1) for computer-navigated total knee arthroplasty (HR = 1.05 [95% CI = 0.98 to 1.12], p = 0.15). There was a significant difference in the rate of revision following non-navigated total knee arthroplasty compared with that following navigated total knee arthroplasty for younger patients (HR = 1.13 [95% CI = 1.03 to 1.25], p = 0.011). Patients less than sixty-five years of age who had undergone non-navigated total knee arthroplasty had a cumulative percent revision of 7.8% (95% CI = 7.5 to 8.2) at nine years compared with 6.3% (95% CI = 5.5 to 7.3) for those who had undergone navigated total knee arthroplasty. Computer navigation led to a significant reduction in the rate of revision due to loosening/lysis (HR = 1.38 [95% CI = 1.13 to 1.67], p = 0.001), which is the most common reason for revision of total knee arthroplasty. Conclusions: Computer navigation reduced the overall rate of revision and the rate revision for loosening/lysis following total knee arthroplasty in patients less than sixty-five years of age. [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]

Background and purpose Recent years have seen a rapid increase in the use of resurfacing hip arthroplasty despite the lack of literature on the long-term outcome. In particular, there is little evidence regarding the outcome of revisions of primary resurfacing. The purpose of this analysis was to examine the survivorship of primary resurfacing hip arthroplasties that have been revised. Patients and methods Over 12,000 primary resurfacing hip arthroplasties were recorded by the Australian Orthopaedic Association National Joint Replacement Registry between September 1, 1999 and December 31, 2008. During this time, 397 revisions for reasons other than infection were reported for these primary resurfacings and classified as acetabular, femoral, or both acetabular and femoral revisions. The survivorship of the different types of revisions was estimated using the Kaplan-Meier method and compared using proportional hazard models. Additionally, the outcome of a femoral-only revision was compared to that of primary conventional total hip arthroplasty. Results Acetabular-only revision had a high risk of re-revision compared to femoral-only and both acetabular and femoral revision (5-year cumulative per cent revision of 20%, 7%, and 5% respectively). Femoral-only revision had a risk of re-revision similar to that of revision of both the acetabular and femoral components. Femoral-only revision had over twice the risk of revision of primary conventional total hip arthroplasty. Interpretation Revision of a primary resurfacing arthroplasty is associated with a major risk of re-revision. The best outcome is achieved when either the femoral-only or both the acetabular and femoral components are revised. Technically straightforward femoral-only revisions generally have a worse outcome than a primary conventional total hip arthroplasty. [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. [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]

Background: Obesity is a known risk factor for the development of hip osteoarthritis. The aim of this study was to investigate whether obesity is associated with the risk of undergoing total hip replacement (THR) in Australia. Methods: A cohort study was conducted comparing data from the Australian Bureau of Statistics and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 2017 to 2018. Body mass index (BMI) data for patients undergoing primary total hip replacement and resurfacing for osteoarthritis were obtained from the AOANJRR. The distribution of THR patients by BMI category was compared to the general population, in age and sex sub‐groups. Results: During the study period, 32 495 primary THR were performed for osteoarthritis in Australia. Compared to the general population, there was a higher prevalence of Class I, II and III obesity in patients undergoing THR in both sexes aged 35–74 years. Class III obese females and males aged 55–64 years were 2.9 and 1.7 times more likely to undergo THR, respectively (P < 0.001). Class III obese females and males underwent THR on average 5.7 and 7.0 years younger than their normal weight counterparts, respectively. Conclusion: Obese Australians are at increased risk of undergoing THR, and at a younger age. [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 aim of this study was to investigate the relationship of obesity with all-cause revision and revision for infection, loosening, instability, and pain after total knee arthroplasty (TKA) performed in Australia.Methods: Data for patients undergoing primary TKA for osteoarthritis from January 1, 2015, to December 31, 2020, were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). The rates of all-cause revision and revision for infection, loosening, instability, and pain were compared for non-obese patients (body mass index [BMI], 18.50 to 29.99 kg/m 2 ), class-I and II obese patients (BMI, 30.00 to 39.99 kg/m 2 ), and class-III obese patients (BMI, ≥40.00 kg/m 2 ). The results were adjusted for age, sex, tibial fixation, prosthesis stability, patellar component usage, and computer navigation usage.Results: During the study period, 141,673 patients underwent primary TKA for osteoarthritis in Australia; of these patients, 48.0% were class-I or II obese, and 10.6% were class-III obese. The mean age was 68.2 years, and 54.7% of patients were female. The mean follow-up period was 2.8 years. Of the 2,655 revision procedures identified, the reasons for the procedures included infection in 39.7%, loosening in 14.8%, instability in 12.0%, and pain in 6.1%. Class-I and II obese patients had a higher risk of all-cause revision (hazard ratio [HR], 1.12 [95% confidence interval (CI), 1.03 to 1.22]; p = 0.007) and revision for infection (HR, 1.25 [95% CI, 1.10 to 1.43]; p = 0.001) than non-obese patients. Class-III obese patients had a higher risk of all-cause revision after 1 year (HR, 1.30 [95% CI, 1.14 to 1.52]; p < 0.001), revision for infection after 3 months (HR, 1.72 [95% CI, 1.33 to 2.17]; p < 0.001), and revision for loosening (HR, 1.39 [95% CI, 1.00 to 1.89]; p = 0.047) than non-obese patients. The risks of revision for instability and pain were similar among groups.Conclusions: Obese patients with knee osteoarthritis should be counseled with regard to the increased risks associated with TKA, so they can make informed decisions about their health care. Health services and policymakers need to address the issue of obesity at a population level.Level Of Evidence: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: New joint replacement prostheses are being continually introduced into the market. The underlying purpose of the introduction of new devices is to improve patient outcomes. This study was undertaken to determine how many new prostheses were associated with improved patient outcomes. Background: Data were obtained from a comprehensive national database. Outcome analysis was performed on all new hip and knee prostheses introduced into the market between January 1, 2003, and December 31, 2007, and used on at least 100 occasions. The findings were compared with the combined results of the three best performing established hip and knee prostheses with a minimum duration of follow-up of five years. The principal outcome measures were the rate of revision per observed component years and the time to first revision, with use of Kaplan-Meier estimates of implant survivorship. Results: Most prostheses introduced into the market during the study period were used on fewer than 100 occasions. Analysis of those that had been used in a sufficient number of procedures showed that 27% (nine of thirty-three) of the hip replacements and 29% (eight of twenty-eight) of the knee replacements had a significantly higher rate of revision than the established prostheses. None of the newer prostheses had a lower rate of revision than the established prostheses. Conclusion: This study indicates that there was no benefit to the introduction of new prostheses into this national market during the five-year study period. Importantly, 30% of the new prostheses were associated with a significantly worse outcome compared with the prostheses with a minimal duration of follow-up of five years. [ABSTRACT FROM AUTHOR]

Background: New joint replacement prostheses are being continually introduced into the market. The underlying purpose of the introduction of new devices is to improve patient outcomes. This study was undertaken to determine how many new prostheses were associated with improved patient outcomes.Background: Data were obtained from a comprehensive national database. Outcome analysis was performed on all new hip and knee prostheses introduced into the market between January 1, 2003, and December 31, 2007, and used on at least 100 occasions. The findings were compared with the combined results of the three best performing established hip and knee prostheses with a minimum duration of follow-up of five years. The principal outcome measures were the rate of revision per observed component years and the time to first revision, with use of Kaplan-Meier estimates of implant survivorship.Results: Most prostheses introduced into the market during the study period were used on fewer than 100 occasions. Analysis of those that had been used in a sufficient number of procedures showed that 27% (nine of thirty-three) of the hip replacements and 29% (eight of twenty-eight) of the knee replacements had a significantly higher rate of revision than the established prostheses. None of the newer prostheses had a lower rate of revision than the established prostheses.Conclusion: This study indicates that there was no benefit to the introduction of new prostheses into this national market during the five-year study period. Importantly, 30% of the new prostheses were associated with a significantly worse outcome compared with the prostheses with a minimal duration of follow-up of five years. [ABSTRACT FROM AUTHOR]

Background: When analyzing the outcomes of joint arthroplasty, an important factor to consider is patient comorbidities. The presence of multiple comorbidities has been associated with longer hospital stays, more postoperative complications, and increased mortality. The American Society of Anesthesiologists (ASA) physical status classification system score is a measure of a patient's overall health and has been shown to be associated with complications and mortality after joint arthroplasty. The Rx-Risk score is another measure for determining the number of different health conditions for which an individual is treated, with a possible score ranging from 0 to 47.Questions/purposes: For patients undergoing THA or TKA, we asked: (1) Which metric, the Rx-Risk score or the ASA score, correlates more closely with 30- and 90-day mortality after TKA or THA? (2) Is the Rx-Risk score correlated with the ASA score?Methods: This was a retrospective analysis of the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) database linked to two other national databases, the National Death Index (NDI) database and the Pharmaceutical Benefits Scheme (PBS), a dispensing database. Linkage to the NDI provided outcome information on patient death, including the fact of and date of death. Linkage to the PBS was performed to obtain records of all medicines dispensed to patients undergoing a joint replacement procedure. Patients were included if they had undergone either a THA (119,076 patients, 131,336 procedures) or TKA (182,445 patients, 215,712 procedures) with a primary diagnosis of osteoarthritis, performed between 2013 and 2017. We excluded patients with missing ASA information (THA: 3% [3055 of 119,076]; TKA: 2% [4095 of 182,445]). This left 127,761 primary THA procedures performed in 116,021 patients (53% [68,037 of 127,761] were women, mean age 68 ± 11 years) and 210,501 TKA procedures performed in 178,350 patients (56% [117,337 of 210,501] were women, mean age 68 ± 9 years) included in this study. Logistic regression models were used to determine the concordance of the ASA and Rx-Risk scores and 30-day and 90-day postoperative mortality. The Spearman correlation coefficient (r) was used to estimate the correlation between the ASA score and Rx-Risk score. All analyses were performed separately for THAs and TKAs.Results: We found both the ASA and Rx-Risk scores had high concordance with 30-day mortality after THA (ASA: c-statistic 0.83 [95% CI 0.79 to 0.86]; Rx-Risk: c-statistic 0.82 [95% CI 0.79 to 0.86]) and TKA (ASA: c-statistic 0.73 [95% CI 0.69 to 0.78]; Rx-Risk: c-statistic 0.74 [95% CI 0.70 to 0.79]). Although both scores were strongly associated with death, their correlation was moderate for patients undergoing THA (r = 0.45) and weak for TKA (r = 0.38). However, the median Rx-Risk score did increase with increasing ASA score. For example, for THAs, the median Rx-Risk score was 1, 3, 5, and 7 for ASA scores 1, 2, 3, and 4, respectively. For TKAs, the median Rx-Risk score was 2, 4, 5, and 7 for ASA scores 1, 2, 3, and 4, respectively.Conclusion: The ASA physical status and RxRisk were associated with 30-day and 90-day mortality; however, the scores were only weakly to moderately correlated with each other. This suggests that although both scores capture a similar level of patient illness, each score may be capturing different aspects of health. The Rx-Risk may be used as a complementary measure to the ASA score.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: THA is a reasonable surgical option for some patients with fragility fractures of the femoral neck, but it has the risk of prosthesis dislocation. The prosthesis combination that reduces the risk of dislocation and the rate of revision surgery is not known.Questions/purposes: In patients receiving primary THA for a femoral neck fracture, does (1) the rate of all-cause revision or (2) the reason for revision and rate of revision for dislocation differ among THA with a standard head size, large head size, dual mobility (DM), or constrained liner? (3) Is there a difference in the revision risk when patients are stratified by age at the time of surgery?Methods: Data were analyzed for 16,692 THAs performed to treat fractures of the femoral neck reported in the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from January 2008 to December 2018, as this included the first use of DM prostheses. The AOANJRR includes information on more than 98% of arthroplasty procedures performed in Australia. Most patients were female (72%) and the mean age was 74 years ± 11. There were 8582 standard-head prostheses, 5820 large-head prostheses, 1778 DM prostheses, and 512 constrained prostheses identified. The cumulative percent revision (CPR) was determined for all causes as well as CPR for dislocation. The time to the first revision was described using Kaplan-Meier estimates of survivorship, with right censoring for death or closure of the database at the time of analysis. The unadjusted CPR was estimated each year of the first 10 years for standard heads, 10 years for large heads, 8 years for constrained liners, and 7 years for DM prostheses, with 95% confidence intervals using unadjusted pointwise Greenwood estimates. The results were adjusted for age, sex, femoral fixation, and head size where appropriate and were considered by age groups < 70 and ≥ 70 years.Results: When adjusted for age, sex, femoral fixation and head size, there was no difference in the rate of all-cause revision at 7 years for any of the four groups. There was no difference in the rate of all-cause revision when patients were stratified by < 70 or ≥ 70 years of age. Dislocation was the most common reason for revision (32%). When analyzing revision for dislocation alone, large-head THA had a lower rate of revision for dislocation compared with standard head (HR 0.6 [95% CI 0.4 to 0.8]; p < 0.001) and DM prostheses had a lower rate of revision for dislocation than standard head for the first 3 months (HR 0.3 [95% CI 0.1 to 0.7]; p < 0.004) but not after this time point.Conclusion: The Australian registry shows that there is no difference in the rate of all-cause revision for standard-head, large-head, DM prostheses or constrained liner THA after femoral neck fractures for all patients or for patients stratified into younger than 70 years and at least 70 years of age groups. Dislocation is the most common cause of revision. Large-head prostheses are associated with a lower revision risk for dislocation and DM prostheses have a lower rate of revision for dislocation than standard heads for the first 3 months only. Surgeons treating a femoral neck fracture with THA might consider a large head size if the diameter of the acetabulum will allow it and a DM prosthesis if a large head size is not possible. The age, life expectancy and level of function of patients with femoral neck fractures minimizes the potential long-term consequences of these prostheses. The lack of significant differences in survival between most prosthesis combinations means surgeons should continue to look for factors beyond head size and prosthesis to minimize dislocation and revision surgery.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Dislocation remains a leading cause of revision following primary and revision total hip arthroplasty (THA). The aim of the present study was to compare the rate of second revision THA following a major first revision for the treatment of dislocation using an implant with a standard, large head, dual-mobility, or constrained acetabular liner.Methods: Data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry from September 1999 through December 2018. All primary THAs that had been performed for the treatment of osteoarthritis and subsequently revised for dislocation were included. All revision THA prostheses with a standard head (≤32 mm), large head (≥36 mm), dual-mobility, or constrained acetabular liner that were used for the first revision procedure were identified. The primary outcome measures were the cumulative rates of second revisions for all causes and for a subsequent diagnosis of dislocation for the 4 different constructs used in the first revision.Results: A total of 1,275 hips underwent a major first revision because of prosthesis dislocation, with 203 of these hips going on to have a second revision. The rate of all-cause second revision was significantly higher in the standard-head group compared with the constrained-acetabular-liner group (hazard ratio [HR], 1.53 [95% confidence interval (CI), 1.01 to 2.30]; p = 0.044). There was no difference in the rates of revision between other articulations. The most common cause of second revision for all implants was dislocation. There were a total of 91 second revisions for a diagnosis of dislocation. Standard heads had a higher rate of second revision compared with constrained acetabular liners (HR, 2.44 [95% CI, 1.30 to 4.60]; p = 0.005), dual-mobility implants (HR, 2.04 [95% CI, 1.03 to 4.01]; p = 0.039), and large heads (HR, 1.80 [95% CI, 1.09, 2.99]; p = 0.022). There was no difference in the rates of second revision between other articulations.Conclusions: Surgeons have a number of options for prostheses when performing a first revision for the treatment of dislocation following a primary THA. The most common cause of a second revision is recurrent dislocation. The use of constrained acetabular liners, dual-mobility liners, and large heads (≥36 mm) are options for reducing subsequent dislocation. Standard head sizes have a higher rate of second revision for further dislocation.Level Of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: A number of surgical approaches are available for total hip arthroplasty (THA), but there are limited large-volume, multi-surgeon data comparing the rates of early revisions following these approaches. The aim of this study was to compare the rate of revision of primary conventional THA related to surgical approach.Methods: Data from the Australian Orthopaedic Association National Joint Replacement Registry were analyzed for all patients who had undergone a primary THA for osteoarthritis from January 2015 to December 2018. The primary outcome measure was the cumulative percent revision (CPR) for all causes. Secondary outcome measures were major revision (a revision procedure requiring change of the acetabular and/or femoral component) and revision for specific diagnoses: fracture, component loosening, infection, and dislocation. Age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) score, femoral head size, and femoral fixation were assessed as potential confounders.Results: There was a total of 122,345 primary conventional THAs for which the surgical approach was recorded in the registry; 65,791 were posterior, 24,468 were lateral, and 32,086 were anterior. There was no difference in the overall CPR among approaches, but the anterior approach was associated with a higher rate of major revisions. There were differences among the approaches with regard to the types of revision. When adjusted for age, sex, ASA score, BMI, femoral head size, and femoral fixation, the anterior approach was associated with a higher rate of femoral complications-i.e., revision for periprosthetic fracture and femoral loosening. There was a lower rate of revision for infection after the anterior approach compared with the posterior approach in the entire period, and compared with the lateral approach in the first 3 months. The posterior approach was associated with a higher rate of revision for dislocation compared with both the anterior and the lateral approach in all time periods. The anterior approach was associated with a lower rate of revision compared with the lateral approach in the first 6 months only.Conclusions: There was no difference in the overall early CPR among the surgical approaches, but the anterior approach was associated with a higher rate of early major revisions and femoral complications (revisions for periprosthetic fracture and femoral loosening) compared with the posterior and lateral approaches and with a lower rate of dislocation and infection.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: 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]

Objectives. To examine the relationships between weight at early and middle adulthood and adult weight gain and the risk of total knee and hip replacement for OA.Methods. At baseline interview during 1990–94, 38 149 participants [mean age 54.9 (s.d. 8.6) years] of the Melbourne Collaborative Cohort Study were asked to recall their weight at age 18–21 years and had their middle age height and weight measured. Total knee and hip replacement for OA between 2001 and 2009 was determined by linking the cohort records to the Australian Orthopaedic Association National Joint Replacement Registry.Results. Greater weight and BMI at age 18–21 years and middle age, weight gain and persistent overweight during this time were associated with an increased risk of total knee and hip replacement. Middle age weight [hazard ratio (HR) per 5 kg 1.25 (95% CI 1.23, 1.27) for knee vs 1.11 (1.09, 1.14) for hip] and BMI [HR per 5 kg/m2 1.80 (1.72, 1.89) vs 1.29 (1.21, 1.37)] and adult weight gain [HR per 5 kg 1.25 (1.23, 1.28) vs 1.10 (1.07, 1.13)] were more strongly associated with the risk of total knee replacement than total hip replacement (P for heterogeneity of HRs <0.0001).Conclusion. Greater body weight and BMI at early and middle adulthood, weight gain and persistent overweight from early to middle adulthood are risk factors for knee and hip OA. Adult weight gain confers stronger risk on knee OA than hip OA. Weight control from early adulthood and avoiding weight gain are important for the prevention of OA. [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% CI, 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. [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]

Background and purpose Despite concerns regarding a higher risk of revision, unicompartmental knee arthroplasty (UKA) continues to be used as an alternative to total knee arthroplasty (TKA). There are, however, limited data on the subsequent outcome when a UKA is revised. We examined the survivorship for primary UKA procedures that have been revised. Methods We used data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) to analyze the survivorship of 1,948 revisions of primary UKA reported to the Registry between September 1999 and December 2008. This was compared to the results of revisions of primary TKA reported during the same period where both the femoral and tibial components were revised. The Kaplan-Meier method for modeling survivorship was used. Results When a primary UKA was revised to another UKA (both major and minor revisions), it had a cumulative per cent revision (CPR) of 28 and 30 at 3 years, respectively. The CPR at 3 years when a UKA was converted to a TKA was 10. This is similar to the 3-year CPR (12) found earlier for primary TKA where both the femoral and tibial components were revised. Interpretation When a UKA requires revision, the best outcome is achieved when it is converted to a TKA. This procedure does, however, have a major risk of re-revision, which is similar to the risk of re-revision of a primary TKA that has had both the femoral and tibial components revised. [ABSTRACT FROM AUTHOR]

Background and purpose The outcome of modern resurfacing remains to be determined. The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) started collection of data on hip resurfacing at a time when modern resurfacing was started in Australia. The rate of resurfacing has been higher in Australia than in many other countries. As a result, the AOANJRR has one of the largest series of resurfacing procedures. This study was undertaken to determine the results of this series and the risk factors associated with revision. Patients and methods Data from the AOANJRR were used to analyze the survivorship of 12,093 primary resurfacing hip replacements reported to the Joint Replacement Registry between September 1999 and December 2008. This was compared to the results of primary conventional total hip replacement reported during the same period. The Kaplan-Meier method and proportional hazards models were used to determine risk factors such as age, sex, femoral component size, primary diagnosis, and implant design. Results Female patients had a higher revision rate than males; however, after adjusting for head size, the revision rates were similar. Prostheses with head sizes of less than 50 mm had a higher revision rate than those with head sizes of 50 mm or more. At 8 years, the cumulative per cent revision of hip resurfacing was 5.3 (4.6–6.2), as compared to 4.0 (3.8–4.2) for total hip replacement. However, in osteoarthritis patients aged less than 55 years with head sizes of 50 mm or more, the 7-year cumulative per cent revision for hip resurfacing was 3.0 (2.2–4.2). Also, hips with dysplasia and some implant designs had an increased risk of revision. Interpretation Risk factors for revision of resurfacing were older patients, smaller femoral head size, patients with developmental dysplasia, and certain implant designs. These results highlight the importance of patient and prosthesis selection in optimizing the outcome of hip resurfacing. [ABSTRACT FROM AUTHOR]

Background: Acute compartment syndrome is a serious and not uncommon complication of limb trauma. The condition is a surgical emergency and is associated with significant morbidity if not diagnosed promptly and treated effectively. Despite the urgency of effective management to minimize the risk of adverse outcomes, there is currently little consensus in the published reports as to what constitutes best practice in the management of acute limb compartment syndrome. Methods: A structured survey was sent to all currently practising orthopaedic surgeons and accredited orthopaedic registrars in Australia to assess their current practice in the management of acute, traumatic compartment syndrome of the leg. Questions were related to key decision nodes in the management process, as identified in a literature review. These included identification of patients at high risk, diagnosis of the condition in alert and unconscious patients, optimal timeframe and technique for carrying out a fasciotomy and management of fasciotomy wounds. Results: A total of 264 valid responses were received, a response rate of 29% of all eligible respondents. The results indicated considerable variation in management of acute compartment syndrome of the leg, in particular in the utilization of compartment pressure measurement and the appropriate pressure threshold for fasciotomy. Of the 78% of respondents who regularly measured compartment pressure, 33% used an absolute pressure threshold, 28% used a differential pressure threshold and 39% took both into consideration. Conclusions: There is variation in the management of acute, traumatic compartment syndrome of the leg in Australia. The development of evidence-based clinical practice guidelines may be beneficial. [ABSTRACT FROM AUTHOR]