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Background: Total hip arthroplasty (THA) is an effective procedure for relieving pain and restoring function in osteoarthritis. A significant proportion of patients have severe disease bilaterally. Consensus regarding safety and selection of patients for simultaneous bilateral THA or the optimal timing for staged THA has not been reached. The aim of this study is to compare rates, causes of revision, and 30-day mortality between simultaneous and staged bilateral THA using data from the Australian Orthopedic National Joint Replacement Registry., Methods: Data for 12,359 bilateral THA procedures were collected from September, 1999 to December, 2017. Rates and causes of revision and 30-day mortality were obtained for simultaneous bilateral and staged procedures with intervals of 1 day-6 weeks, 6 weeks-3 months, and 3 months-6 months. Yearly cumulative percent revision or cumulative percent survival with 95% confidence intervals calculated by the Kaplan-Meier method, and adjusted hazard ratios were used for comparisons., Results: Thirty-day mortality is lower in patients who have bilateral procedures within 6 months, regardless of timing, than those who have unilateral procedures (0.06% vs 0.18%). Staged bilateral THA had a significantly lower mortality than simultaneous bilateral THA (odds ratio 0.175, 95% confidence interval = 0.04-0.78, P = .022). When separate time intervals were compared, no significant differences were seen. Bilateral 6 week-3 months has a higher rate of revision from 1.5 years-2years compared with same day bilaterals (hazard ratio = 2.39, 95% confidence interval = 1.12, 5.09, P = .024). There were no other significant differences in the rate of revision between groups. The most common reasons for revision were fracture, loosening, and infection. Simultaneous bilateral procedures have a significantly higher rate of revision for fracture compared with staging 3-6 months (hazard ratio = 1.96 [1.27, 3.03], P = .002)., Conclusion: This study demonstrates that bilateral THA has a low mortality rate regardless of time interval between procedures. Simultaneous and staged bilateral THA have similar rates of revision., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Hip arthroplasty is increasing in Australia. The number of procedures for fractured neck of femur was 7500 in 2017. Best practices for fixation method and procedure type require scrutiny. This paper is about the costs and health outcomes of cemented and uncemented hemiarthroplasty and total hip arthroplasty at a national level., Methods: We created a Markov model for patients <75, aged 75-85, and over 85. Expected costs and health outcomes over 5 years from a decision to change from existing practice to a best practice policy in which all patients with fractured neck of femur received the same fixation method based on age and type of arthroplasty are estimated. The model was populated using prevalence and incidence data from the Australian Orthopedic Association National Joint Replacement Registry, costs from Metro North Hospital and Health Service in Queensland, and probabilities and utilities from the literature. We simulated the uncertainties in outcomes with probabilistic sensitivity analysis., Results: We found that uncemented stem procedures were more costly and provided worse health outcomes compared to cemented stem fixation for hemiarthroplasty and total hip arthroplasty for all age groups. Moving from existing practice to cemented stem arthroplasty could save the Australian health system $2.0 million over 5 years with a gain of 203 quality-adjusted life years., Conclusion: We suggest that consideration be given to cemented fixation of the femoral stem for patients receiving both hemiarthroplasty and total hip arthroplasty for fractured neck of femur. Best practice guidelines focused on cost-effectiveness should recommend cemented stem fixation to both save costs and improve patient quality of life., (Copyright © 2020 Elsevier Inc. All rights reserved.)

We aimed to describe the epidemiology, multi-drug resistance and seasonal distribution of bacteria cultured within 12 months following lower limb orthopaedic surgery in tropical and subtropical Australian hospitals between 2010 and 2017. We collected data from four tropical and two subtropical hospitals. Categorical variables were examined using the Pearson Chi-squared test or Fisher's Exact test, and continuous variables with the Student t-test or Mann-Whitney U test. A Poisson regression model was used to examine the relationship between season, weather and the incidence of Staphylococcus and nonfermentative species. We found that at tropical sites, nonfermenters ( Pseudomonas aeruginosa and Acinetobacter baumannii ) were more common (28.7% vs. 21.6%, p = 0.018), and patients were more likely to culture multi-drug-resistant (MDR) nonfermenters (11.4% vs. 1.3%, p = 0.009) and MDR Staphylococcus aureus (35.9% vs. 24.6%, p = 0.006). At tropical sites, patients were more likely to be younger (65.9 years vs. 72.0, p = < 0.001), male (57.7% vs. 47.8%, p = 0.005), having knee surgery (45.3% vs. 34.5%, p = 0.002) and undergoing primary procedures (85.0% vs. 73.0%, p = < 0.001). Species were similar between seasons in both tropical and subtropical hospitals. Overall, we found that following lower limb orthopaedic surgery in tropical compared with subtropical Australia, patients were more likely to culture nonfermenters and some MDR species.

Background: Patellar resurfacing in total knee arthroplasty (TKA) remains a controversial issue after more than 4 decades of TKA. Despite a growing body of evidence from registry data, resurfacing is still based largely on a surgeon's preference and training. The purpose of this study is to provide long-term outcomes for patellar resurfaced compared to when the patella is not resurfaced., Methods: Data from the Australian Orthopaedic Association National Joint Replacement Registry (1999-2017) were used for this study. The analysis included 570,735 primary TKAs undertaken for osteoarthritis. Hazard ratios (HRs) and 17-year cumulative percent revision rates were used to compare revision rates between 4 subgroups: minimally stabilized (MS) patellar resurfacing, posterior stabilized (PS) patellar resurfacing, MS unresurfaced, and PS unresurfaced patella. Additional analyses of the patellar implant type and a comparison of inlay and onlay patellar resurfacing were also performed., Results: For all primary TKA, procedures where the patella was not resurfaced have a higher rate of revision compared to procedures where the patella was resurfaced (HR, 1.31; confidence interval, 1.28-1.35; P < .001). Unresurfaced PS knees have the highest cumulative percent revision at 17 years (11.1%), followed by MS unresurfaced (8.8%), PS resurfaced (7.9%), and MS resurfaced (7.1%). Inlay patellar resurfacing has a higher rate of revision compared to onlay patellar resurfacing (HR, 1.27; confidence interval, 1.17-1.37; P < .001)., Conclusion: Resurfacing the patella reduces the rate of revision for both MS and PS knees. MS knees with patellar resurfacing have the lowest rate of revision. Onlay patella designs are associated with a lower revision rate compared to inlay patella designs., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: The declining popularity of cemented acetabular components is incongruous, given the published results of prostheses implanted using contemporary techniques. The outcome of arthroplasty has previously been demonstrated to correlate with surgeon experience and volume of practice. We aim to explore if surgeon volume alters outcomes of cemented acetabular components based on survivorship data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR)., Methods: An observational study was undertaken using a cohort of 22,956 patients with a primary diagnosis of osteoarthritis in the period 2003-2016 in whom cemented acetabular components were implanted. The cohort was stratified by age (greater than or less than 65 years) and annualized surgical volume of ≤10, >10-≤25, and >25 cases., Results: Stratified by age and volume, there was a protective benefit against revision conveyed at volume thresholds of 10 cases per annum and 25 cases per annum for patients ≥65 years of age and <65 years of age, respectively., Conclusion: Cemented total hip arthroplasty has excellent survivorship out to 15 years based on AOANJRR data. This survivorship is further improved if surgeons perform a higher volume of cases, with >25 cases conferring the greatest benefit. The AOANJRR data set is used to define best practice; surgeons who choose to utilize cemented acetabular fixation should be encouraged to perform this technique in adequate volumes to minimize revision risk and ensure the preservation of this important surgical skill set., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Computer navigation and image-derived instrumentation (IDI) are technology-based methods developed to improve outcomes and potentially reduce revision total knee arthroplasty (TKA). IDI refers to the use of manufactured, patient-specific surgical jigs. Conflicting reports exist on IDI-associated improvements in outcomes. The primary aim of the current study was to compare the rates of revision among TKA cases in which components were initially implanted with use of IDI, computer navigation, or neither of these methods ("other" TKA). The secondary aim was to determine whether the outcomes of IDI differed for specific subgroups., Methods: Data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) for the 3 TKA groups: IDI, computer-navigated, and other TKA. The study period was from the first IDI procedure recorded by the AOANJRR (April 2010) to December 31, 2016. The analysis was restricted to primary TKA cases undertaken for osteoarthritis and involving patellar resurfacing and the use of a cross-linked polyethylene insert. Subanalyses were performed to evaluate the effects of age, sex, implantation method, IDI manufacturer, prosthetic design, and prosthesis type on the rates of revision. Kaplan-Meier estimates of survivorship described the time to first revision. Hazard ratios (HRs, Cox proportional hazards models) with adjustment for age and sex were used to compare revision rates., Results: IDI was used in 5,486 primary TKA procedures. There was no significant difference among the groups in the cumulative percent revision (CPR) at 5 years: 3.3% (95% confidence interval [CI], 2.4% to 4.6%) for IDI, 2.4% (95% CI, 2.2% to 2.7%) for the computer-navigated group, and 2.5% (95% CI, 2.3% to 2.7%) for other TKA. Posterior-stabilized TKA with use of the IDI method had a significantly higher rate of revision at >3 months (HR, 1.45 [95% CI, 1.02 to 2.04]; p = 0.036), as did IDI TKA in the ≤65-year-old patient cohort (HR, 1.52 [95% CI, 1.10 to 2.09]; p = 0.010), compared with computer-navigated TKA. Patellar revision was significantly more likely in the IDI group., Conclusions: IDI TKA demonstrated no overall difference in early to mid-term revision rates compared with standard implantation methods. However, elevated rates of revision were seen with posterior-stabilized TKA, in patients ≤65 years of age, and for patellar revision, meaning that this method should be used with some caution and requires further study., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: The influence of obesity measured in terms of body mass index (BMI) on the complication rates following total hip arthroplasty (THA) is a matter of debate., Methods: This retrospective study conducted at a tertiary referral centre at Brisbane, Australia, examines the association between BMI and in-hospital postoperative complications, length of operating time and duration of hospital stay in 964 patients, who underwent THA from 2006 to 2010., Results: Amongst patients undergoing primary THA, when compared to the normal weight patients, those with BMI between 25 kg/m 2 and 29.9 kg/m 2 (overweight) and those with BMI between 35 kg/m 2 and 39.9 kg/m 2 (obese class II) had lower odds of perioperative complications (odds ratio [OR]: 0.62 (95% confidence intervals [CI], 0.43-0.92, p = 0.016) and OR: 0.60 (95% CI, 0.36- 0.99, p = 0.047 respectively). Patients with BMI less than or equal to 40 kg/m 2 were also associated with significantly lower odds of cardiac complications ( p = 0.02). With unadjusted regression analysis, it was noted that those with BMI ≥40 kg/m 2 had the highest odds of developing infectious complications (OR 2.68, 95% CI, 1.08-6.65, p < 0.05). As the BMI increased, there was a statistically significant increase in length of operating time ( p < 0.001)., Conclusion: There is a significant impact of BMI on the occurrence of perioperative complications following THA. Compared to normal weight category, the overweight and obese class II patients had a lower likelihood of developing overall, especially cardiac complications. Length of operating time increases along with an increase in BMI.

Background: Total knee arthroplasty (TKA) is an effective procedure for relieving pain and restoring function in osteoarthritis, with a significant proportion of patients having severe disease bilaterally. However, although there are differences in patient selection criteria for bilateral procedures, there is no consensus regarding the optimal timing for bilateral TKA. The aim of this study was to compare rates and causes of revision and 30-day mortality between simultaneous and staged bilateral TKA using data from the Australian Orthopaedic Association National Joint Replacement Registry., Methods: Data for over 36,000 bilateral TKAs were collected from September 1999 to December 2015. Rates and causes of revision and 30-day mortality rates were obtained for simultaneous bilateral and staged procedures with intervals of 1 day-6 weeks, 6 weeks-3 months, and 3-6 months. Yearly cumulative percent revision or cumulative percent survival with 95% confidence intervals calculated using the Kaplan-Meier method and adjusted hazard ratios were used for comparisons., Results: There was no significant difference between revision rates or reasons for revision between staged bilateral and simultaneous TKA (hazard ratio 1.09 [95% confidence interval {CI} 0.85-1.40; P = .511] for 1 day-6 weeks, 0.93 [95% CI 0.77-1.14; P = .494] for 6 weeks-3 months, and 1.10 [95% CI 0.98-1.23; P = .115] for 3-6 months). The most common reasons for revision were loosening/lysis and infection. The 30-day mortality rates were lower in the 6 weeks-3 months group than simultaneous bilaterals (P = .007)., Conclusion: This study demonstrates that simultaneous and staged bilateral TKA have similar rates of revision over the medium term but that 30-day mortality is reduced in the 6 weeks-3 months group., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Surgical site infection (SSI) is associated with substantial costs for health services, reduced quality of life, and functional outcomes. The aim of this study was to evaluate the cost-effectiveness of strategies claiming to reduce the risk of SSI in hip arthroplasty in Australia., Methods: Baseline use of antibiotic prophylaxis (AP) was compared with no antibiotic prophylaxis (no AP), antibiotic-impregnated cement (AP + ABC), and laminar air operating rooms (AP + LOR). A Markov model was used to simulate long-term health and cost outcomes of a hypothetical cohort of 30,000 total hip arthroplasty patients from a health services perspective. Model parameters were informed by the best available evidence. Uncertainty was explored in probabilistic sensitivity and scenario analyses., Results: Stopping the routine use of AP resulted in over Australian dollars (AUD) $1.5 million extra costs and a loss of 163 quality-adjusted life years (QALYs). Using antibiotic cement in addition to AP (AP + ABC) generated an extra 32 QALYs while saving over AUD $123,000. The use of laminar air operating rooms combined with routine AP (AP + LOR) resulted in an AUD $4.59 million cost increase and 127 QALYs lost compared with the baseline comparator., Conclusion: Preventing deep SSI with antibiotic prophylaxis and antibiotic-impregnated cement has shown to improve health outcomes among hospitalized patients, save lives, and enhance resource allocation. Based on this evidence, the use of laminar air operating rooms is not recommended., (Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.)

Background: The treatment for deep surgical site infection (SSI) following primary total hip arthroplasty (THA) varies internationally and it is at present unclear which treatment approaches are used in Australia. The aim of this study is to identify current treatment approaches in Queensland, Australia, show success rates and quantify the costs of different treatments., Methods: Data for patients undergoing primary THA and treatment for infection between January 2006 and December 2009 in Queensland hospitals were extracted from routinely used hospital databases. Records were linked with pathology information to confirm positive organisms. Diagnosis and treatment of infection was determined using ICD-10-AM and ACHI codes, respectively. Treatment costs were estimated based on AR-DRG cost accounting codes assigned to each patient hospital episode., Results: A total of n=114 patients with deep surgical site infection were identified. The majority of patients (74%) were first treated with debridement, antibiotics and implant retention (DAIR), which was successful in eradicating the infection in 60.3% of patients with an average cost of $13,187. The remaining first treatments were 1-stage revision, successful in 89.7% with average costs of $27,006, and 2-stage revisions, successful in 92.9% of cases with average costs of $42,772. Multiple treatments following 'failed DAIR' cost on average $29,560, for failed 1-stage revision were $24,357, for failed 2-stage revision were $70,381 and were $23,805 for excision arthroplasty., Conclusions: As treatment costs in Australia are high primary prevention is important and the economics of competing treatment choices should be carefully considered. These currently vary greatly across international settings.

Background and Purpose: The appropriate fixation method for hemiarthroplasty of the hip as it relates to implant survivorship and patient mortality is a matter of ongoing debate. We examined the influence of fixation method on revision rate and mortality., Methods: We analyzed approximately 25,000 hemiarthroplasty cases from the AOA National Joint Replacement Registry. Deaths at 1 day, 1 week, 1 month, and 1 year were compared for all patients and among subgroups based on implant type., Results: Patients treated with cemented monoblock hemiarthroplasty had a 1.7-times higher day-1 mortality compared to uncemented monoblock components (p < 0.001). This finding was reversed by 1 week, 1 month, and 1 year after surgery (p < 0.001). Modular hemiarthroplasties did not reveal a difference in mortality between fixation methods at any time point., Interpretation: This study shows lower (or similar) overall mortality with cemented hemiarthroplasty of the hip.

Background: Patella resurfacing in total knee arthroplasty is a contentious issue. The literature suggests that resurfacing of the patella is based on surgeon preference, and little is known about the role and timing of resurfacing and how this affects outcomes., Methods: We analyzed 134,799 total knee arthroplasties using data from the Australian Orthopaedic Association National Joint Replacement Registry. Hazards ratios (HRs) were used to compare rates of early revision between patella resurfacing at the primary procedure (the resurfacing group, R) and primary arthroplasty without resurfacing (no-resurfacing group, NR). We also analyzed the outcomes of NR that were revised for isolated patella addition., Results: At 5 years, the R group showed a lower revision rate than the NR group: cumulative per cent revision (CPR) 3.1% and 4.0%, respectively (HR = 0.75, p < 0.001). Revisions for patellofemoral pain were more common in the NR group (17%) than in the R group (1%), and "patella only" revisions were more common in the NR group (29%) than in the R group (6%). Non-resurfaced knees revised for isolated patella addition had a higher revision rate than patella resurfacing at the primary procedure, with a 4-year CPR of 15% and 2.8%, respectively (HR = 4.1, p < 0.001)., Interpretation: Rates of early revision of primary total knees were higher when the patella was not resurfaced, and suggest that surgeons may be inclined to resurface later if there is patellofemoral pain. However, 15% of non-resurfaced knees revised for patella addition are re-revised by 4 years. Our results suggest an early beneficial outcome for patella resurfacing at primary arthroplasty based on revision rates up to 5 years.

Routine postsurgery assessment of primary total hip arthroplasty (THA) is recommended in many countries. Whether the benefits of this activity are justified by the costs is not known. We used a decision-analytic Markov model to compare the costs and health outcomes of 3 different follow-up strategies after primary THA. If there is no routine follow-up of patients for 7 years after primary THA, there would be cost savings between AU$6.5 and $11.9 million and gains of between 1.8 and 8.8 quality-adjusted life years. Policy makers should investigate less resource-intensive alternatives to common routine postsurgical assessment., (2010 Elsevier Inc. All rights reserved.)