A comparison of cemented femoral fixation via anterior versus posterior approach total hip arthroplasty: an analysis of 60,739 total hip arthroplasties.

BACKGROUND: Anterior approach total hip arthroplasty (THA) decreases the rate of dislocation but increases femoral-sided complications in the way of periprosthetic fractures and component loosening. A cemented prosthesis may reduce femoral-sided complications and improve the risk:benefit profile of anterior approach THA. METHODS: Data from the Australian National Joint Replacement Registry were analysed for patients undergoing primary THA via the anterior or posterior approach using a cemented polished femoral stem from January 2015 to December 2021. The primary outcome measure was the cumulative percent revision (CPR) for all causes and CPR for femoral component loosening and fracture. The CPR for the primary outcome measures were compared between the anterior and posterior approach and adjusted for age, sex, ASA score, BMI and femoral head size. RESULTS: The study included 60,739 THAs with cemented stems (10,742 anterior, 49,997 posterior). The rate of revision of the anterior versus the posterior approach did not significantly differ (HR 0.87 (95% CI, 0.74-1.03), p = 0.100). Anterior approach THA had a significantly higher rate of revision for femoral component loosening (HR 5.06 [95% CI, 3.08-8.30], p < 0.001); and a decreased rate of revision for infection (HR 0.59 [95% CI, 0.43-0.81], p = 0.001) and dislocation/instability (HR 0-3 months 0.48 [95% CI, 0.27-0.83], p = 0.008; HR >3 months 0.30 [95% CI, 0.15-0.61], p < 0.001). There was no difference in the rate of revision surgery for fracture between the 2 approaches (HR 1.01 [95% CI, 0.71-1.43]), p = 0.975). CONCLUSIONS: There is no significant difference in overall revision rates with cemented femoral fixation performed with an anterior or posterior approach. Cemented fixation performed with the anterior approach partly mitigates femoral complications with no difference in the revision rate for fracture but an increased rate of femoral component loosening.

Effect of Aspirin vs Enoxaparin on 90-Day Mortality in Patients Undergoing Hip or Knee Arthroplasty: A Secondary Analysis of the CRISTAL Cluster Randomized Trial.

Importance: Ischemic heart disease remains the leading cause of mortality following hip and knee arthroplasty. Due to its antiplatelet and cardioprotective properties, aspirin has been proposed as an agent that could reduce mortality when used as venous thromboembolism (VTE) prophylaxis following these procedures. Objective: To compare aspirin with enoxaparin in reducing 90-day mortality for patients undergoing hip or knee arthroplasty procedures. Design, Setting, and Participants: This study was a planned secondary analysis of the CRISTAL cluster randomized, crossover, registry-nested trial performed across 31 participating hospitals in Australia between April 20, 2019, and December 18, 2020. The aim of the CRISTAL trial was to determine whether aspirin was noninferior to enoxaparin in preventing symptomatic VTE following hip or knee arthroplasty. The primary study restricted the analysis to patients undergoing total hip or knee arthroplasty for a diagnosis of osteoarthritis only. This study includes all adult patients (aged ≥18 years) undergoing any hip or knee arthroplasty procedure at participating sites during the course of the trial. Data were analyzed from June 1 to September 6, 2021. Interventions: Hospitals were randomized to administer all patients oral aspirin (100 mg daily) or subcutaneous enoxaparin (40 mg daily) for 35 days after hip arthroplasty and 14 days after knee arthroplasty procedures. Main Outcomes and Measures: The primary outcome was mortality within 90 days. The between-group difference in mortality was estimated using cluster summary methods. Results: A total of 23 458 patients from 31 hospitals were included, with 14 156 patients allocated to aspirin (median [IQR] age, 69 [62-77] years; 7984 [56.4%] female) and 9302 patients allocated to enoxaparin (median [IQR] age, 70 [62-77] years; 5277 [56.7%] female). The mortality rate within 90 days of surgery was 1.67% in the aspirin group and 1.53% in the enoxaparin group (estimated difference, 0.04%; 95% CI, -0.05%-0.42%). For the subgroup of 21 148 patients with a nonfracture diagnosis, the mortality rate was 0.49% in the aspirin group and 0.41% in the enoxaparin group (estimated difference, 0.05%; 95% CI, -0.67% to 0.76%). Conclusions and Relevance: In this secondary analysis of a cluster randomized trial comparing aspirin with enoxaparin following hip or knee arthroplasty, there was no significant between-group difference in mortality within 90 days when either drug was used for VTE prophylaxis. Trial Registration: http://anzctr.org.au Identifier: ACTRN12618001879257.

Obesity is associated with an increased risk of undergoing hip replacement in Australia.

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.

Obesity is associated with an increased risk of undergoing shoulder arthroplasty in Australia.

BACKGROUND: The aim of this study was to examine the incidence of overweight and obesity in patients undergoing primary total shoulder arthroplasty (TSA) for osteoarthritis (OA) in Australia compared to the incidence of obesity in the general population. MATERIALS AND METHODS: A 2017/18 cohort consisting of 2997 patients from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) who underwent TSA were compared with matched controls from the Australian Bureau of Statistics (ABS) National Health Survey from the same time period. The 2 groups were analyzed according to body mass index (BMI) category, sex, and age. RESULTS: According to the 2017/18 National Health Survey, 35.6% of Australian adults were overweight and 31.3% were obese. Of the primary TSA cases performed, 34.9% were overweight and 50.1% were obese. The relative risk of requiring TSA for OA increased with increasing BMI category. Class III obese females, aged 55-64, were 8.6 times more likely to receive a TSA compared to their normal weight counterparts. Males in the same age and BMI category were 2.5 times more likely. Class III obese patients underwent TSA 4 years (female) and 6 years (male) younger than their normal weight counterparts. CONCLUSION: Obesity significantly increases the risk of requiring TSA. The association appears to be particularly strong for younger females.

The association between body mass index and patient-reported outcome measures before and after primary total hip or knee arthroplasty: a registry.

BACKGROUND: The objective is to determine whether body mass index is associated with patient-reported expectations and well-being before primary total hip or total knee arthroplasty, and patient-reported outcomes 6 months after surgery. METHODS: Data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. Outcome measures included pre-operative expectations for post-operative mobility, joint pain and health, pre- and post-operative EQ-5D-5L, EQ-VAS, Oxford Hip/Knee Scores and joint pain scales, and post-operative perceived change and perceived satisfaction. Associations with BMI were assessed using chi-square tests, analysis of variance and Linear Mixed Models equations. RESULTS: Data were available for 12 816 primary THA patients and 20 253 primary TKA patients. Pre-operatively, patients in higher BMI categories were significantly more likely to expect ongoing problems with mobility, more joint pain and poorer health following surgery (P<0.01 for all analyses). For arthroplasty patients, higher BMI was associated with poorer pre-operative and post-operative scores for all measures. BMI was positively associated with improvements in EQ-5D, OHS/KS and joint pain. While between-group differences were statistically significant, many were small in magnitude. There was no association between BMI and patient-perceived change or satisfaction after arthroplasty. CONCLUSION: Patients undergoing THA/TKA, higher BMI was associated with lower pre-operative expectations, poorer well-being before surgery, and worse scores after surgery. Patients who were obese demonstrated comparable satisfaction with their operated joint, compared with non-obese patients. BMI was associated with greater pre- to post-operative improvements in outcome scores for EQ-5D, VAS knee, OHS/OKS and joint pain but these differences may not be clinically important.

Hip Arthroplasty Outcomes in the Presence of Kidney Failure: A National Data Linkage Study.

BACKGROUND: Patients who have kidney failure are at higher risk of requiring total hip arthroplasty (THA) and are at higher risk of complications. This study compared the rate of revision surgery and mortality following THA between patients who have kidney failure receiving long term dialysis or who had a kidney transplant and those who did not have kidney failure. METHODS: A data linkage study was performed using data from 2 national registries: a registry of dialysis and kidney transplant patients and a registry of THA procedures. Both registries had coverage of almost all procedures or treatments in Australia. Data from September 1999 to December 2016 were used. Mortality and revision surgery were compared between patients receiving dialysis, those who had a functioning kidney transplant, and patients who did not have kidney failure using Cox and Fine-Gray (competing risk) regression models. A total of 383,478 primary THA procedures were identified as people receiving dialysis (n = 490), who had a functioning kidney transplant (n = 459), or who did not have kidney failure (n = 382,529). RESULTS: There was no significant difference in the overall rate of revision surgery between the groups (dialysis versus no kidney failure HR = 1.20; 95% CI 0.76, 1.88, transplant versus no kidney failure (hazard ratio) HR = 1.01; 95% (confidence interval) CI 0.66, 1.53). The risk for death after surgery was significantly higher in the dialysis group compared to both the functioning transplant group (HR = 3.44; 95%CI 1.58, 7.5), and in those without kidney failure (HR = 4.13; 95%CI 3.25, 5.25). CONCLUSION: The rate of mortality after THA in patients on dialysis is higher than in patients who have a functioning transplant or those who do not have kidney failure, but there is no early excess mortality to suggest a difference in this metric due to the surgery.

Antibiotic utilisation in primary and revision total hip replacement patients: A registry linkage cohort study of 106 253 patients using the Australian Orthopaedic Association National Joint Replacement Registry.

PURPOSE: Infection is a major complication following joint replacement (JR) surgery. However, little data exist regarding antibiotic utilisation following primary JR and how use changes with subsequent revision surgery. This study aimed to examine variation in antibiotic utilisation rates before and after hip replacement surgery in those revised for infection, revised for other reasons and those without revision. METHODS: This retrospective cohort analysis used linked data from the Australian Orthopaedic Association National Joint Replacement Registry and Australian Government Pharmaceutical Benefits Scheme. Patients were included if undergoing total hip replacement (THR) for osteoarthritis in private hospitals between 2002 and 2017. Three groups were examined: primary THR with no subsequent revision (n = 102 577), primary THR with a subsequent revision for reasons other than periprosthetic joint infection (PJI) (n = 3156) and primary THR with a subsequent revision for PJI (n = 520). Monthly antibiotic utilisation rates and prevalence rate ratios (PRRs) with 95% confidence intervals (CIs) were calculated in the 2 years pre- and post-THR. RESULTS: Prior to primary THR antibiotic utilisation was 9%-10%. After primary THR, antibiotic utilisation rates were higher among patients revised for PJI (PRR 1.69, 95% CI 1.60-1.79) compared to non-revised patients, while the utilisation rate was lower in patients revised for reasons other than infection (PRR 0.96, 95% CI 0.93-0.98). For those revised for infection, antibiotic utilisation post-revision surgery was two times higher than those revised for other reasons (PRR 2.16, 95% CI 2.08-2.23). Utilisation of injectable antibiotics including, vancomycin, flucloxacillin and cephazolin was higher in those revised for PJI patients 0-2 weeks following surgery but not in those revised for other reasons compared to the non-revised group. CONCLUSIONS: Ongoing antibiotic utilisation after primary surgery may be an early signal of problems with the THR and should be a prompt for primary care physicians to refer patients to specialists for further appropriate investigations and management.

No increased risk of cancer associated with metal-on-metal or ceramic-on-ceramic procedures compared to other bearing surfaces in patients with total hip arthroplasty: A nationwide linked registry cohort analysis of 167,837 patients.

OBJECTIVES: Studies have identified increased cancer risk among patients undergoing total hip arthroplasty (THA) compared to the general population. However, evidence of all-cause and site-specific cancer risk associated with different bearing surfaces has varied, with previous studies having short latency periods with respect to use of modern Metal-on-Metal (MoM) bearings. Using the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) linked to Australasian Association of Cancer Registries data, our aim was to evaluate risk of all-cause and site-specific cancer according to bearing surfaces in patients undergoing THA for osteoarthritis and whether risk increased with MoM bearings. METHODS: Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated by comparing number of observed cancer cases to expected number based on incidence rate in the Australian population. All-cause and site-specific cancer rates were calculated for all conventional stemmed THA (csTHA) and resurfacing THA (rsTHA) procedures performed for osteoarthritis. Cox proportional hazards models were used to compare cancer rates for MoM, ceramic-on-ceramic (CoC) and resurfacing procedures with a comparison group comprising metal-on-polyethylene (MoP) or ceramic-on-polyethylene (CoP) procedures. RESULTS: There were 156,516 patients with csTHA procedures and 11,321 with rsTHA procedures for osteoarthritis performed between 1999 and 2012. Incidence of all-cause cancer was significantly higher for csTHA (SIR 1.24, 95% CI 1.22-1.26) and rsTHA (SIR 1.74, 95% CI 1.39-2.04) compared to the Australian population. For csTHA, there was no significant difference in all-site cancer rates for MoM (Hazard Ratio (HR) 1.01, 95%CI 0.96-1.07) or CoC (HR 0.98, 95%CI 0.94-1.02) compared to MoP and CoP bearings. Significantly increased risk of melanoma, non-Hodgkins lymphoma, myeloma, leukaemia, prostate, colon, bladder and kidney cancer was found for csTHA and, prostate cancer, melanoma for rsTHA procedures when compared to the Australian population, although risk was not significantly different across bearing surfaces. CONCLUSIONS: csTHA and rsTHA procedures were associated with increased cancer incidence compared to the Australian population. However, no excess risk was observed for MoM or CoC procedures compared to other bearing surfaces.

Estimating incidence rates of periprosthetic joint infection after hip and knee arthroplasty for osteoarthritis using linked registry and administrative health data.

AIMS: The aim of this study was to estimate the 90-day periprosthetic joint infection (PJI) rates following total knee arthroplasty (TKA) and total hip arthroplasty (THA) for osteoarthritis (OA). METHODS: This was a data linkage study using the New South Wales (NSW) Admitted Patient Data Collection (APDC) and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), which collect data from all public and private hospitals in NSW, Australia. Patients who underwent a TKA or THA for OA between 1 January 2002 and 31 December 2017 were included. The main outcome measures were 90-day incidence rates of hospital readmission for: revision arthroplasty for PJI as recorded in the AOANJRR; conservative definition of PJI, defined by T84.5, the PJI diagnosis code in the APDC; and extended definition of PJI, defined by the presence of either T84.5, or combinations of diagnosis and procedure code groups derived from recursive binary partitioning in the APDC. RESULTS: The mean 90-day revision rate for infection was 0.1% (0.1% to 0.2%) for TKA and 0.3% (0.1% to 0.5%) for THA. The mean 90-day PJI rates defined by T84.5 were 1.3% (1.1% to 1.7%) for TKA and 1.1% (0.8% to 1.3%) for THA. The mean 90-day PJI rates using the extended definition were 1.9% (1.5% to 2.2%) and 1.5% (1.3% to 1.7%) following TKA and THA, respectively. CONCLUSION: When reporting the revision arthroplasty for infection, the AOANJRR substantially underestimates the rate of PJI at 90 days. Using combinations of infection codes and PJI-related surgical procedure codes in linked hospital administrative databases could be an alternative way to monitor PJI rates.Cite this article: Bone Joint J 2022;104-B(9):1060-1066.

What Is the Outcome of the First Revision Procedure of Primary THA for Osteoarthritis? A Study From the Australian Orthopaedic Association National Joint Replacement Registry.

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.

Is the Revision Rate for Femoral Neck Fracture Lower for Total Hip Arthroplasty Than for Hemiarthroplasty?: A Comparison of Registry Data for Contemporary Surgical Options.

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.

Effect of Aspirin vs Enoxaparin on Symptomatic Venous Thromboembolism in Patients Undergoing Hip or Knee Arthroplasty: The CRISTAL Randomized Trial.

Importance: There remains a lack of randomized trials investigating aspirin monotherapy for symptomatic venous thromboembolism (VTE) prophylaxis following total hip arthroplasty (THA) or total knee arthroplasty (TKA). Objective: To determine whether aspirin was noninferior to enoxaparin in preventing symptomatic VTE after THA or TKA. Design, Setting, and Participants: Cluster-randomized, crossover, registry-nested trial across 31 hospitals in Australia. Clusters were hospitals performing greater than 250 THA or TKA procedures annually. Patients (aged ≥18 years) undergoing hip or knee arthroplasty procedures were enrolled at each hospital. Patients receiving preoperative anticoagulation or who had a medical contraindication to either study drug were excluded. A total of 9711 eligible patients were enrolled (5675 in the aspirin group and 4036 in the enoxaparin group) between April 20, 2019, and December 18, 2020. Final follow-up occurred on August 14, 2021. Interventions: Hospitals were randomized to administer aspirin (100 mg/d) or enoxaparin (40 mg/d) for 35 days after THA and for 14 days after TKA. Crossover occurred after the patient enrollment target had been met for the first group. All 31 hospitals were initially randomized and 16 crossed over prior to trial cessation. Main Outcomes and Measures: The primary outcome was symptomatic VTE within 90 days, including pulmonary embolism and deep venous thrombosis (DVT) (above or below the knee). The noninferiority margin was 1%. Six secondary outcomes are reported, including death and major bleeding within 90 days. Analyses were performed by randomization group. Results: Enrollment was stopped after an interim analysis determined the stopping rule was met, with 9711 patients (median age, 68 years; 56.8% female) of the prespecified 15 562 enrolled (62%). Of these, 9203 (95%) completed the trial. Within 90 days of surgery, symptomatic VTE occurred in 256 patients, including pulmonary embolism (79 cases), above-knee DVT (18 cases), and below-knee DVT (174 cases). The symptomatic VTE rate in the aspirin group was 3.45% and in the enoxaparin group was 1.82% (estimated difference, 1.97%; 95% CI, 0.54%-3.41%). This failed to meet the criterion for noninferiority for aspirin and was significantly superior for enoxaparin (P = .007). Of 6 secondary outcomes, none were significantly better in the enoxaparin group compared with the aspirin group. Conclusions and Relevance: Among patients undergoing hip or knee arthroplasty for osteoarthritis, aspirin compared with enoxaparin resulted in a significantly higher rate of symptomatic VTE within 90 days, defined as below- or above-knee DVT or pulmonary embolism. These findings may be informed by a cost-effectiveness analysis. Trial Registration: ANZCTR Identifier: ACTRN12618001879257.

Impact of patient and prosthesis characteristics on common reasons for total knee replacement revision: a registry study of 36,626 revision cases from Australia, Sweden, and USA.

BACKGROUND AND PURPOSE: Total knee replacement (TKR) studies usually analyze all-cause revision when considering relationships with patient and prosthesis factors. We studied how these factors impact different revision diagnoses. PATIENTS AND METHODS: We used data from 2003 to 2019 of TKR for osteoarthritis from the arthroplasty registries of Sweden, Australia, and Kaiser Permanente, USA to study patient and prosthesis characteristics for specific revision diagnoses. There were 1,072,924 primary TKR included and 36,626 were revised. Factors studied included age, sex, prosthesis constraint, fixation method, bearing mobility, polyethylene type, and patellar component use. Revision diagnoses were arthrofibrosis, fracture, infection, instability, loosening, pain, patellar reasons, and wear. Odds ratios (ORs) for revision were estimated and summary effects were calculated using a meta-analytic approach. RESULTS: We found between-registry consistency in 15 factor/reason analyses. Risk factors for revision for arthrofibrosis were age < 65 years (OR 2.0; 95% CI 1.4-2.7) and mobile bearing designs (MB) (OR 1.7; CI 1.1-2.5), for fracture were female sex (OR 3.2; CI 2.2-4.8), age ≥ 65 years (OR 2.8; CI 1.9-4) and posterior stabilized prostheses (PS) (OR 2.1; CI 1.3-3.5), for infection were male sex (OR 1.9; CI 1.7-2.0) and PS (OR 1.5; CI 1.2-1.8), for instability were age < 65 years (OR 1.5; CI 1.3-1.8) and MB (OR 1.5; CI 1.1-2.2), for loosening were PS (OR 1.5; CI 1.4-1.6), MB (OR 2.2; CI 1.6-3.0) and use of ultra-high molecular weight polyethylene (OR 2.3; CI 1.8-2.9), for patellar reasons were not resurfacing the patella (OR 13.6; CI 2.1-87.2) and MB (OR 2.0; CI 1.2-3.3) and for wear was cementless fixation (OR 4.9; CI 4.3-5.5). INTERPRETATION: Patients could be counselled regarding specific age and sex risks. Use of minimally stabilized, fixed bearing, cemented prostheses, and patellar components is encouraged to minimize revision risk.

Poor Knee-specific and Generic Patient-reported Outcome Measure Scores at 6 Months Are Associated With Early Revision Knee Arthroplasty: A Study From the Australian Orthopaedic Association National Joint Replacement Registry.

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.

Reduced Revision Rates in Total Shoulder Arthroplasty With Crosslinked Polyethylene: Results From the Australian Orthopaedic Association National Joint Replacement Registry.

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.

The Association Between Preoperative Patient-Reported Health Status and Postoperative Survey Completion Following Arthroplasty: Registry-Based Cohort Study.

BACKGROUND: Patient-reported outcome measures (PROMs) are commonly used to report outcomes after hip and knee arthroplasty, but response rates are rarely complete. Given that preoperative health status (as measured by PROMs) is a strong predictor of outcomes (using the same measures) and that these outcomes may influence the response rate, it is possible that postoperative response rates (the proportion of patients providing preoperative PROMs who also provide postoperative PROMs) may be influenced by preoperative health status. OBJECTIVE: This study aims to test the association between preoperative PROMs and postoperative response status following hip and knee arthroplasty. METHODS: Data from the PROMs program of the Australian national joint registry were used. The preoperative PROMs were the Oxford Hip Score or Oxford Knee Score, The EQ-5D Utility Index, and the EQ visual analog scale (VAS) for overall health. Logistic regression, adjusting for age, sex, BMI, and the American Society of Anesthesiologists (ASA) Physical Status Classification System, was used to test the association between each preoperative PROM and response status for the 6-month postsurgery survey. RESULTS: Data from 9499 and 16,539 patients undergoing elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) for osteoarthritis, respectively, were included in the analysis. Adjusting for age, sex, BMI, and ASA, there was no significant difference in response status at the postoperative follow-up based on the preoperative Oxford Hip or Knee Scores (odds ratio [OR] 1.00, 95% CI 0.99-1.01 for both; P=.70 for THA and P=.85 for TKA). Healthier patients (based on the EQ VAS scores) preoperatively were more likely to respond postoperatively, but this difference was negligible (OR 1.00, 95% CI 1.00-1.01 for THA and TKA; P=.004 for THA and P<.001 for TKA). The preoperative EQ Utility Index was not associated with the postoperative response rate for THA (OR 1.14, 95% CI 0.96-1.36; P=.13) or TKA patients (OR 1.05, 95% CI 0.91-1.22; P=.49). CONCLUSIONS: The likelihood of responding to a postoperative PROMs survey for patients undergoing hip or knee arthroplasty was not associated with clinically important differences in preoperative patient-reported joint pain, function, or health-related quality of life. This suggests that the assessment of postoperative outcomes in hip and knee arthroplasty is not biased by differences in preoperative health measures between responders and nonresponders.

Between-hospital and between-surgeon variation in thresholds for hip and knee replacement.

BACKGROUND: Total hip replacement (THR) and total knee replacement (TKR) are cost-effective interventions to reduce pain and disability associated with osteoarthritis, however there is no clear guidelines available to determine appropriate patient selection and the timing of surgery. This prospective cohort study aimed to evaluate the hospital- and surgeon-level variation in the severity of patient-reported symptoms prior to THR and TKR. METHODS: Patients undergoing primary THR (n = 4330) or TKR (n = 7054) for osteoarthritis who participated in a national registry-led Patient Reported Outcome Measures (PROMs) pilot program were included in the analysis. Pre-operative Oxford Hip Score (OHS) and Oxford Knee Score (OKS) (range 0-48; representing worst to best hip/knee pain and function) data were examined for variation between private and public hospitals and between surgeons using linear mixed models. RESULTS: Pre-operative mean OHS was significantly higher (better) in patients whose surgery was performed in a private hospital compared to public hospitals; 21.39 versus 18.11 (mean difference 3.27, 95% CI 1.75, 4.79). For OKS, the difference between private hospital and public hospital scores was dependent on BMI and gender. Most of the variation in pre-operative OHS and OKS was not at the individual hospital- or surgeon-level, which explained only a negligible proportion of the model variance (⟨5%) for THR and TKR. CONCLUSION: Apart from a difference between private and public hospitals, there was little between-hospital or between-surgeon symptom variation in joint-specific pain and function prior to THR or TKR. The findings suggest consistency in the surgical thresholds for patients being offered hip and knee joint replacement procedures.

Minimal Clinically Important Changes in HOOS-12 and KOOS-12 Scores Following Joint Replacement.

BACKGROUND: For patient-reported outcome measures (PROMs) to provide meaningful information to support clinical care, we need to understand the magnitude of change that matters to patients. The aim of this study was to estimate minimal clinically important changes (MCICs) for the 12-item Hip disability and Osteoarthritis Outcome Score (HOOS-12) and Knee injury and Osteoarthritis Outcome Score (KOOS-12) among people undergoing joint replacement for osteoarthritis. METHODS: Individual-level data from the Australian Orthopaedic Association National Joint Replacement Registry's pilot PROMs program were used for this analysis. Preoperative and 6-month postoperative HOOS-12 and KOOS-12 domain and summary impact scores plus a rating of patient-perceived change after surgery (on a 5-point scale ranging from "much worse" to "much better") were available. Three anchor-based approaches-mean change, receiver operating characteristics (ROC) based on Youden's J statistic, and predictive modeling using a binary logistic regression model-were used to calculate MCICs based on patient-perceived change. RESULTS: Data were available for 1,490 patients treated with total hip replacement (THR) (mean age, 66 years; 54% female) and 1,931 patients treated with total knee replacement (TKR) (mean age, 66 years; 55% female). Using the mean change method, the MCIC ranged from 24.0 to 27.5 points for the HOOS-12 and 17.5 to 21.8 points for the KOOS-12. The ROC analyses generated comparable MCIC values (28.1 for HOOS-12 and a range of 15.6 to 21.9 for KOOS-12) with high sensitivity and specificity. Lower estimates were derived from predictive modeling following adjustment for the proportion of improved patients (range, 15.7 to 19.2 for HOOS-12 and 14.2 to 16.5 for KOOS-12). CONCLUSIONS: We report MCIC values for the HOOS-12 and KOOS-12 instruments that we derived using 3 different methods. As estimates obtained using predictive modeling can be adjusted for the proportion of improved patients, these may be the most clinically applicable. These MCIC values can be used to interpret important changes in pain, function, and quality of life from the patient's perspective. LEVELS OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

A Comparison of Revision Rates and Dislocation After Primary Total Hip Arthroplasty with 28, 32, and 36-mm Femoral Heads and Different Cup Sizes: An Analysis of 188,591 Primary Total Hip Arthroplasties.

UPDATE: This article was updated on August 17, 2022, because of previous errors, which were discovered after the preliminary version of the article was posted online. On page 1462, in the first sentence of the Abstract section entitled "Results," the phrase that had read "and 36-mm heads had fewer dislocations than 28-mm (HR = 0.33 [95% CI, 0.16 to 0.68]; p = 0.003), but more dislocations than 32-mm heads (HR for >2 weeks = 2.25 [95% CI, 1.13 to 4.49]; p = 0.021)" now reads "and 36-mm heads had fewer dislocations than 28-mm (HR = 0.33 [95% CI, 0.16 to 0.68]; p = 0.003) and 32-mm heads (HR for ≥2 weeks = 0.44 [95% CI, 0.22 to 0.88]; p = 0.021)." On page 1468, in the last sentence of the section entitled "Acetabular Components with a Diameter of <51 mm," the phrase that had read "and HR for ≥2 weeks = 2.25 [95% CI, 1.13 to 4.49; p = 0.021]) ( Fig. 3 )" now reads "and HR for ≥2 weeks = 0.44 [95% CI, 0.22 to 0.88; p = 0.021]) ( Fig. 3 )." Finally, on page 1466, in the upper right corner of Figure 3 , under "32mm vs 36mm," the second line that had read "2Wks+: HR=2.25 (1.13, 4.49), p=0.021" now reads "2Wks+: HR=0.44 (0.22, 0.88), p= 0.021."

The acetabular component diameter can influence the choice of femoral head size in total hip arthroplasty (THA). We compared the rates of revision by femoral head size for different acetabular component sizes. Data from the Australian Orthopaedic Association National Joint Replacement Registry were analyzed for patients undergoing primary THA for a diagnosis of osteoarthritis from September 1999 to December 2019. Acetabular components were stratified into quartiles by size: <51 mm, 51 to 53 mm, 54 to 55 mm, and 56 to 66 mm. Femoral head sizes of 28 mm, 32 mm, and 36 mm were compared for each cup size. The primary outcome was the cumulative percent revision (CPR) for all aseptic causes and for dislocation. The results were adjusted for age, sex, femoral fixation, femoral head material, year of surgery, and surgical approach and were stratified by femoral head material. For acetabular components of <51 mm, 32-mm (hazard ratio [HR] = 0.75 [95% confidence interval (CI), 0.57 to 0.97]; p = 0.031) and 36-mm femoral heads (HR = 0.58 [95% CI, 0.38 to 0.87]; p = 0.008) had a lower CPR for aseptic causes than 28-mm heads; and 36-mm heads had fewer dislocations than 28-mm (HR = 0.33 [95% CI, 0.16 to 0.68]; p = 0.003), and 32-mm heads (HR for ≥2 weeks = 0.44 [95% CI, 0.22 to 0.88]; p = 0.021). For 51 to 53-mm, 54 to 55-mm, and 56 to 66-mm-diameter acetabular components, there was no difference in the CPR for aseptic causes among head sizes. A femoral head size of 36 mm had fewer dislocations in the first 2 weeks than a 32-mm head for the 51 to 53-mm acetabular components (HR for <2 weeks = 3.79 [95% CI, 1.23 to 11.67]; p = 0.020) and for the entire period for 56 to 66-mm acetabular components (HR = 1.53 [95% CI, 1.05 to 2.23]; p = 0.028). The reasons for revision differed for each femoral head size. There was no difference in the CPR between metal and ceramic heads. There is no clear advantage to any single head size except with acetabular components of <51 mm, in which 32-mm and 36-mm femoral heads had lower rates of aseptic revision. If stability is prioritized, 36-mm femoral heads may be indicated. Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.