Australian Orthopaedic Association National Joint Research Articles

Lifetime Risk of Primary Shoulder Arthroplasty From 2008 to 2017: A Population-Level Analysis Using National Registry Data.

To estimate the lifetime risk of primary shoulder arthroplasty in Australia and to examine changes over time. For this retrospective population-level analysis, de-identified individual-level data on all primary partial shoulder arthroplasty (PSA) and total shoulder arthroplasty (TSA) procedures performed in Australia from 2008 to 2017 (n = 38,868) were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. Population data and life tables were obtained from the Australian Bureau of Statistics. Lifetime risk of primary shoulder arthroplasty was calculated for each year using a standardized formula. Separate calculations were undertaken by sex and for PSA and TSA. The lifetime risk of shoulder arthroplasty increased significantly over time. For men, this risk more than doubled from 0.78% (95% confidence interval [95% CI] 0.73-0.84) in 2008 to 1.78% (95% CI 1.70-1.86) in 2017. Lifetime risk for women rose from 1.54% (95% CI 1.46-1.62) to 2.88% (95% CI 2.78-2.99) over the study period. This increase was predominantly driven by growth in lifetime risk of TSA. In contrast, lifetime risk of PSA decreased over time, from 0.25% (95% CI 0.22-0.28) in 2008 to 0.11% (95% CI 0.09-0.13) in 2017 for men, and from 0.55% (95% CI 0.51-0.60) to 0.11% (95% CI 0.09-0.13) for women. By the end of 2017, the lifetime risk of primary shoulder arthroplasty in Australia increased to 1 in 57 for men and 1 in 35 for women. Compared to declining PSA trends, there was substantial growth in TSA use over a decade. These data improve our understanding of the rising national burden of primary shoulder arthroplasty and can assist in planning to meet future surgical demand.

CRISTAL (a cluster-randomised, crossover, non-inferiority trial of aspirin compared to low molecular weight heparin for venous thromboembolism prophylaxis in hip or knee arthroplasty, a registry nested study): statistical analysis plan

BackgroundThis a priori statistical analysis plan describes the analysis for CRISTAL.MethodsCRISTAL (cluster-randomised, crossover, non-inferiority trial of aspirin compared to low molecular weight heparin for venous thromboembolism prophylaxis in hip or knee arthroplasty, a registry nested study) aims to determine whether aspirin is non-inferior to low molecular weight heparin (LMWH) in preventing symptomatic venous thromboembolism (VTE) following hip arthroplasty (HA) or knee arthroplasty (KA). The study is nested within the Australian Orthopaedic Association National Joint Replacement Registry. The trial was commenced in April 2019 and after an unplanned interim analysis, recruitment was stopped (December 2020), as the stopping rule was met for the primary outcome.The clusters comprised hospitals performing > 250 HA and/or KA procedures per annum, whereby all adults (> 18 years) undergoing HA or KA were recruited. Each hospital was randomised to commence with aspirin, orally, 85–150 mg daily or LMWH (enoxaparin), 40 mg, subcutaneously, daily within 24 h postoperatively, for 35 days after HA and 14 days after KA. Crossover was planned once the registration target was met for the first arm.The primary end point is symptomatic VTE within 90 days. Secondary outcomes include readmission, reoperation, major bleeding and death within 90 days, and reoperation and patient-reported pain, function and health status at 6 months.The main analyses will focus on the primary and secondary outcomes for patients undergoing elective primary total HA and KA for osteoarthritis. The analysis will use an intention-to-treat approach with cluster summary methods to compare treatment arms. As the trial stopped early, analyses will account for incomplete cluster crossover and unequal cluster sizes.ConclusionsThis paper provides a detailed statistical analysis plan for CRISTAL.Trial registrationAustralian and New Zealand Clinical Trials Registry ACTRN12618001879257. Registered on 19/11/2018.

CORR Insights®: Collection and Reporting of Patient-reported Outcome Measures in Arthroplasty Registries: Multinational Survey and Recommendations.

CORR Insights®: Collection and Reporting of Patient-reported Outcome Measures in Arthroplasty Registries: Multinational Survey and Recommendations.

CORR Insights®: A Comparison of Revision Rates for Osteoarthritis of Primary Reverse Total Shoulder Arthroplasty to Primary Anatomic Shoulder Arthroplasty with a Cemented All- polyethylene Glenoid: Analysis from the Australian Orthopaedic Association National Joint Replacement Registry.

CORR Insights®: A Comparison of Revision Rates for Osteoarthritis of Primary Reverse Total Shoulder Arthroplasty to Primary Anatomic Shoulder Arthroplasty with a Cemented All- polyethylene Glenoid: Analysis from the Australian Orthopaedic Association National Joint Replacement Registry.

Does a Prescription-based Comorbidity Index Correlate with the American Society of Anesthesiologists Physical Status Score and Mortality After Joint Arthroplasty? A Registry Study.

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. 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? 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. 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. 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 III, therapeutic study.

Are responders to patient health surveys representative of those invited to participate? An analysis of the Patient-Reported Outcome Measures Pilot from the Australian Orthopaedic Association National Joint Replacement Registry.

Patient-reported outcome measures (PROMs) are commonly used to evaluate surgical outcome in patients undergoing joint replacement surgery, however routine collection from the target population is often incomplete. Representative samples are required to allow inference from the sample to the population. Although higher capture rates are desired, the extent to which this improves the representativeness of the sample is not known. We aimed to measure the representativeness of data collected using an electronic PROMs capture system with or without telephone call follow up, and any differences in PROMS reporting between electronic and telephone call follow up. Data from a pilot PROMs program within a large national joint replacement registry were examined. Telephone call follow up was used for people that failed to respond electronically. Data were collected pre-operatively and at 6 months post-operatively. Responding groups (either electronic only or electronic plus telephone call follow up) were compared to non-responders based on patient characteristics (joint replaced, bilaterality, age, sex, American Society of Anesthesiologist (ASA) score and Body Mass Index (BMI)) using chi squared test or ANOVA, and PROMs for the two responder groups were compared using generalised linear models adjusted for age and sex. The analysis was restricted to those undergoing primary elective hip, knee or shoulder replacement for osteoarthritis. Pre-operatively, 73.2% of patients responded electronically and telephone follow-up of non-responders increased this to 91.4%. Pre-operatively, patients responding electronically, compared to all others, were on average younger, more likely to be female, and healthier (lower ASA score). Similar differences were found when telephone follow up was included in the responding group. There were little (if any) differences in the post-operative comparisons, where electronic responders were on average one year younger and were more likely to have a lower ASA score compared to those not responding electronically, but there was no significant difference in sex or BMI. PROMs were similar between those reporting electronically and those reporting by telephone. Patients undergoing total joint replacement who provide direct electronic PROMs data are younger, healthier and more likely to be female than non-responders, but these differences are small, particularly for post-operative data collection. The addition of telephone call follow up to electronic contact does not provide a more representative sample. Electronic-only follow up of patients undergoing joint replacement provides a satisfactory representation of the population invited to participate.

The Use of Computer Navigation in Total Hip Arthroplasty Is Associated with a Reduced Rate of Revision for Dislocation: A Study of 6,912 Navigated THA Procedures from the Australian Orthopaedic Association National Joint Replacement Registry.

The use of computer navigation has been shown to produce more accurate cup positioning when compared with non-navigated total hip arthroplasty (THA), but so far there is only limited evidence to show its effect on clinical outcomes. The present study analyzed data from the Australian Orthopaedic Association National Joint Replacement Registry to assess the impact of computer navigation on the rates of all-cause revision and revision for dislocation following THA. Data for all non-navigated and navigated primary THAs performed for osteoarthritis in Australia from January 1, 2009, to December 31, 2019, were examined to assess the rate of revision. We analyzed the effects of navigation on rate, reason, and type of revision. Hazard ratios (HRs) from Cox proportional hazard models, adjusted for age, sex, and head size, were utilized. Because of known prosthesis-specific differences in outcomes, we performed a further analysis of the 5 acetabular and femoral component combinations most commonly used with navigation. Computer navigation was utilized in 6,912 primary THAs for osteoarthritis, with the use of navigation increasing from 1.9% in 2009 to 4.4% of all primary THAs performed in 2019. There was no difference in the rate of all-cause revision between navigated and non-navigated THAs looking at the entire group. There was a lower rate of revision for dislocation in the navigation THA cohort. The cumulative percent revision for dislocation at 10 years was 0.4% (95% confidence interval [CI], 0.2% to 0.6%) for navigated compared with 0.8% (95% CI, 0.8% to 0.9%) for non-navigated THAs (HR adjusted for age, sex, and head size, 0.46; 95% CI, 0.29 to 0.74; p = 0.002). In the 5 component combinations most commonly used with navigation, the rate of all-cause revision was significantly lower when these components were navigated compared with non-navigated. The cumulative percent revision at 10 years for these 5 prostheses combined was 2.4% (95% CI, 1.6% to 3.4%) for navigated compared with 4.2% (95% CI, 4.0% to 4.5%) for non-navigated THAs (HR, 0.64; 95% CI, 0.48 to 0.86; p = 0.003). This study showed that the use of computer navigation was associated with a reduced rate of revision for dislocation following THA. Furthermore, in the component combinations most commonly used with navigation there was also a reduction in the rate of all-cause revision. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Shoulder Joint Arthroplasty in Young Patients: Analysis of 8742 Patients from the Australian Orthopaedic Association National Joint Replacement Registry

Shoulder Joint Arthroplasty in Young Patients: Analysis of 8742 Patients from the Australian Orthopaedic Association National Joint Replacement Registry

Five-Year Outcomes of Pyrocarbon Humeral Resurfacing Arthroplasty in Young Patients: Analysis from the Australian Orthopaedic Association National Joint Replacement Registry

Five-Year Outcomes of Pyrocarbon Humeral Resurfacing Arthroplasty in Young Patients: Analysis from the Australian Orthopaedic Association National Joint Replacement Registry

Short-Term Follow-Up of the PROSTALAC Implant for Primary Total Hip Arthroplasty in Patients with an Infected Native/Total Hip

AbstractInfection after a total hip replacement (THR) is a significant complication for patients and is costly for health services. The two-stage Prosthesis with Antibiotic Loaded Acrylic (PROSTALAC) procedure has been the gold standard treatment for managing THR infections. The aim of this study is to evaluate using a one-stage PROSTALAC procedure as an alternative for patients who would otherwise not be able to undergo THR surgery due to a previous hip infection.We evaluated nine cases where the PROSTALAC implant was used in the native hip. The reasons for surgery, clinical results, and complications were reviewed. An Australian Orthopaedic Association National Joint Replacement Registry data report verified that no patients were revised outside of our local center.All patients reported symptomatic relief and satisfactory function, one patient had a peri-prosthetic fracture after experiencing a fall, and one patient underwent surgery for loosening of the joint. No cases were revised to another implant or had further infection. Minimum follow-up was 2 years.Our results suggest that this implant is useful in patients with osteoarthritis of the hip with a history of previous infection or chronic infection of the native hip.

CORR Insights®: Do Fixed or Mobile Bearing Implants Have Better Survivorship in Medial Unicompartmental Knee Arthroplasty? A Study From the Australian Orthopaedic Association National Joint Replacement Registry.

CORR Insights®: Do Fixed or Mobile Bearing Implants Have Better Survivorship in Medial Unicompartmental Knee Arthroplasty? A Study From the Australian Orthopaedic Association National Joint Replacement Registry.

A Comparison of Revision Rates for Dislocation and Aseptic Causes Between Dual Mobility and Large Femoral Head Bearings in Primary Total Hip Arthroplasty With Subanalysis by Acetabular Component Size: An Analysis of 106,163 Primary Total Hip Arthroplasties

BackgroundDual mobility (DM) and large femoral head bearings (≥36 mm) both decrease the risk of dislocation in total hip arthroplasty (THA). There is limited comparable data in primary THA. This study compared the revision rates for dislocation and aseptic causes between DM and large femoral heads and subanalyzed by acetabular component size. MethodsData from the Australian Orthopedic Association National Joint Replacement Registry were analyzed for patients undergoing primary THA for osteoarthritis from January 2008 (the year of first recorded DM use) to December 2019. All DM and large femoral head bearings were identified. The primary outcome measure was the cumulative percent revision (CPR) for dislocation and for all aseptic causes. The results were adjusted by age, sex, and femoral fixation. A subanalysis was performed stratifying acetabular component diameter <58 m and ≥58 mm. ResultsThere were 4942 DM and 101,221 large femoral head bearings recorded. There was no difference in the CPR for dislocation (HR = 0.69 (95% CI 0.42, 1.13), P = .138) or aseptic causes (HR = 0.91 (95% CI 0.70, 1.18), P = .457). When stratified by acetabular component size, DM reduced the CPR for dislocation in acetabular component diameter <58 mm (HR = 0.55 (95% CI 0.30, 1.00), P = .049). There was no difference for diameter ≥58 mm. There was no difference in aseptic revision when stratified by acetabular component diameter. ConclusionThere is no difference in revision rates for dislocation or aseptic causes between DM and large femoral heads in primary THA. When stratified by acetabular component size, DM reduces dislocation for acetabular component diameter <58 mm. Level of EvidenceLevel III.

Performance of the HOOS-12 and KOOS-12 instruments for evaluating outcomes from joint replacement surgery

To evaluate the psychometric properties of the 12-item Hip disability and Osteoarthritis Outcome Score (HOOS-12) and Knee injury and Osteoarthritis Outcome Score (KOOS-12) for use in evaluating outcomes after joint replacement for osteoarthritis. Patient-reported outcomes data collected by the Australian Orthopaedic Association National Joint Replacement Registry were used for this analysis. HOOS-12 and KOOS-12 domain (pain, function, quality of life) and summary impact data were available. The Oxford Hip Score (OHS), Oxford Knee Score (OKS) and EQ-5D-5L were used as comparators. Instruments were administered pre-operatively and at 6months post-operatively. Internal consistency reliability, floor and ceiling effects, convergent validity, known groups validity, and responsiveness were evaluated using standard psychometric techniques. Baseline HOOS-12 and KOOS-12 data were available for 3,023 patients undergoing primary total hip replacement and 4,010 patients undergoing primary total knee replacement. At baseline, high internal consistency was demonstrated for all domains and summary scores (Cronbach's alpha: HOOS-12=0.81-0.93; KOOS-12=0.82-0.92). Post-operative ceiling effects (>15% of patients scoring the best possible score) were identified for the HOOS-12 pain (46%), function (39%) and quality of life domains (26%) and summary score (17%), and for the KOOS-12 pain (21%) and function domains (18%). The HOOS-12 and KOOS-12 could differentiate between two known groups (lowest/highest OHS or OKS quartiles post-operatively; p<0.001) and were highly responsive to change (effect sizes for HOOS-12: 2.20-2.83; KOOS-12: 1.82-2.35). The HOOS-12 and KOOS-12 have good psychometric properties for capturing joint replacement outcomes including excellent responsiveness, although ceiling effects may limit monitoring of post-operative improvement.

Implications for research and clinical use from a Rasch analysis of the HOOS-12 and KOOS-12 instruments

To evaluate the structural validity of the 12-item Hip disability and Osteoarthritis Outcome Score (HOOS-12) and 12-item Knee injury and Osteoarthritis Outcome Score (KOOS-12) using Rasch analysis and consider psychometric implications for research and clinical use. Individual-level HOOS-12 and KOOS-12 data from the Australian Orthopaedic Association National Joint Replacement Registry, collected before and after primary total hip and knee replacement, were used for this analysis. Using the Rasch analytic approach, overall model fit and item fit were examined, together with potential reasons for misfit including response threshold ordering, differential item functioning, internal consistency, unidimensionality and item targeting. Overall misfit to the Rasch model was evident for both instruments. A degree of item misfit was also observed, although most items demonstrated logical sequencing of response options. Only two items (hip/knee pain frequency and awareness of hip/knee problems) displayed disordered response thresholds. The pain, function, and quality of life domains of the HOOS-12 and KOOS-12 demonstrated excellent internal consistency reliability (person separation index: 0.80-0.93) and unidimensionality. A mismatch between item difficulty and person ability scores at the highest end of the HOOS-12 and KOOS-12 scales contributed to post-operative ceiling effects (mean logit for HOOS-12: 3.57; KOOS-12: 2.58; ≈0 indicates well-targeted scale). We found evidence to support the structural validity of the three HOOS-12 and KOOS-12 domains for evaluating joint replacement outcomes. However, there may be missing content in both instruments particularly for high-functioning patients. Minor refinement of some response options may be warranted to improve item performance.

Acetabular screws do not improve early revision rates in primary total hip arthroplasty. An instrumented registry analysis.

Initial stability of uncemented acetabular components in total hip arthroplasty (THA) is important for osseointegration and potentially enhanced by screw fixation. We used Australian Orthopaedic Association National Joint Replacement Registry data to determine whether screw usage influences uncemented acetabular component survival. Primary THA with uncemented acetabular components performed for osteoarthritis from 1999 to 2018 was included. Survivorship was calculated using Kaplan-Meier estimates of cumulative percent revision (CPR). Comparisons used Cox proportional hazards method. An instrumental variable analysis adjusted for surgeon preference for screws as a confounding factor was used. Three hundred thirty thousand one hundred ninety-two THAs were included (31.8% with screws, 68.2% without). Two hundred twenty thousand six hundred seven were included in the instrumental variable analysis. Revision rate of acetabular components (all causes) was higher with screws during the first six years (hazard ratio (HR) = 1.45 (95% CI 1.34, 1.57), p < 0.001) and lower thereafter (HR = 0.81 (95% CI 0.67, 0.98), p = 0.027). Revision rate of acetabular components for loosening was higher with screws over the entire study period (HR = 1.73 (95% CI 1.51, 1.98), p < 0.001). Overall THA revision rate was higher with screws during the first six years (HR = 1.20 (95% CI 1.15, 1.26), p < 0.001) but lower thereafter (HR = 0.89 (95% CI 0.81, 0.98), p = 0.020). Revision rate for dislocation was higher with screws over the entire period (HR = 1.16 (95% CI 1.06, 1.26), p < 0.001). Instrumental variable analysis revealed higher revision rates with acetabular screws in the first six years. (HR = 1.18 (95% CI 1.09-1.29), p < 0.001). Screws did not confer a protective effect against acetabular loosening and were not associated with long-term negative consequences.

Lifetime Risk of Revision Hip Replacement Surgery in Australia Remains Low: A Population-Level Analysis Using National Registry Data.

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

The rate of 2nd revision for shoulder arthroplasty as analyzed by the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR)

Background and purpose — The increase in shoulder arthroplasty may lead to a burden of revision surgery. This study compared the rate of (2nd) revision following aseptic 1st revision shoulder arthroplasty, considering the type of primary, and the class and type of the revision. Patients and methods — All aseptic 1st revisions of primary total reverse shoulder arthroplasty (rTSA group) and of primary total stemmed and stemless total shoulder arthroplasty (non-rTSA group) procedures reported to our national registry between April 2004 to December 2018 were included. The rate of 2nd revision was determined using Kaplan–Meier estimates and comparisons were made using Cox proportional hazards models. Results — There was an increased risk of 2nd revision in the 1st month only for the rTSA group (n = 700) compared with the non-rTSA group (n = 991); hazard ratio (HR) = 4.8 (95% CI 2.2–9). The cumulative percentage of 2nd revisions (CPR) was 24% in the rTSA group and 20% in the non-rTSA group at 8 years. There was an increased risk of 2nd revision for the type (cup vs. head) HR = 2.2 (CI 1.2–4.2), but not class of revision for the rTSA group. Minor (> 3 months) vs. major class revision, and humeral revision vs. all other revision types were second revision risk factors for the non-rTSA group. Interpretation — The CPR of revision shoulder arthroplasty was > 20% at 8 years and was influenced by the type of primary, the class, and the type of revision. The most common reasons for 2nd revision were instability/dislocation, loosening, and infection.

Antibiotic Dispensing Before and After Primary and Revision Total Hip Replacement: An Australian Orthopaedic Association National Joint Replacement Registry Linkage Study

IntroductionInfection is a major complication following joint replacement (JR) surgery. However, little data exist on baseline use of antibiotics following primary JR and how use changes with subsequent revision surgery.&#x0D; Objectives &amp; ApproachOur study objectives were to describe community use of antibiotics before and after primary total hip replacement (THR) and change in use pre and post revision procedure.&#x0D; Registry data were linked with national medication dispensing data using probabilistic record linkage. Patients with THR for osteoarthritis in a private hospital between 1999 and 2017 were included. Three groups were analysed: patients with primary procedures revised for infection, revised for non-infection reasons and those not revised. Rate of antibiotic dispensing/month was calculated as number of patients dispensed at least one antibiotic in a given month divided by number of patients at-risk.&#x0D; ResultsThere were 102,577 patients included in the non-revised group, 3,156 revised for non-infection and 520 revised for infection. Prior to primary THR, baseline antibiotic dispensing rate was 9-11%/month in all groups. Post-primary rates were similar (10-11%) for non-revised and revised non-infection patients but higher (16-17%) for revised-infection patients. In 1, 6 and 12 months preceding revision for infection, antibiotic use was 55%, 27% and 22%, respectively. For patients revised for non-infection, antibiotic use was 21%, 14%, 13%, respectively. One-month following revision for infection, 82% of patients were dispensed antibiotics, remaining high (38%) at 6-months and 28% at 12-months. In the revision non-infection group, antibiotic use was 48% first month post-surgery, reducing rapidly to 15% at 6-months.&#x0D; Conclusion / ImplicationsNon-revision and revision non-infection patients had similar antibiotic dispensing before and after surgery. Revision infection patients however, maintained higher antibiotic dispensing post-primary, pre and post revision. This may reflect either ongoing infection, need for long-term suppressive therapy or reluctance of treating physicians to terminate treatment.

Validating Australian Government Medicare Benefits Schedule Data Against the National Joint Replacement Registry Data

IntroductionTo enhance the value of the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) we recently linked these data with administrative datasets including, Medicare Benefits Schedule (MBS) and Pharmaceutical Benefits Scheme (PBS). Understanding the validity of administrative data is important in establishing the reliability of these data for informing clinical practice and policy.&#x0D; Objectives &amp; ApproachThe study objective was to determine the validity of MBS data for capturing the occurrence of a joint replacement procedure. Using the AOANJRR procedures as the gold standard, we determined the sensitivity of the MBS data in correctly identifying hip joint replacement procedures.&#x0D; ResultsOf the 178,047 patients with a single primary total hip replacement occurring in a private hospital setting and recorded in the AOANJRR, 76% had a same-day MBS service claim indicative of that procedure, 2% had MBS procedures within +/- 7 days of the procedure while 18% had no MBS procedure codes indicative of a total hip joint replacement procedure. Of the procedures with no total hip MBS codes, 2% had MBS procedures codes indicating a total knee procedure, 1.7% had MBS procedure codes indicating a revision hip on that day and 13% of procedures had an in-hospital MBS hip anaesthetic administration code claimed on that day.&#x0D; Conclusion / ImplicationsGiven the increasing application of MBS data to describe health service use it is important to understand the validity of these data for identifying procedures undertaken in the private hospital setting. Using validated, gold standard data captured by the AOANJRR we identified that MBS data likely underestimate the occurrence of total hip replacement procedures. In addition, some MBS procedure codes are misattributed to other procedure types such as knee procedures and revision procedures.

Enhancing Joint Replacement Outcomes Through Registry Linkage with National Health Administrative Data in Australia

IntroductionMonitoring of joint replacement (JR) data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) has reduced revision rates and improved surgical practice. Outcome assessment post-arthroplasty is limited however, to revision (reoperation) surgery and mortality outcomes. The AOANJRR National Data Linkage project seeks to broaden the scope of outcomes investigation in Australia by linking registry and health administrative datasets.&#x0D; Objectives and ApproachUsing linked registry and administrative data, the project seeks to describe and quantify national/regional trends and variation in major complications (infection, dislocation, arthrofibrosis, chronic pain, venous thromboembolism, cardiac events), malignancy and health service utilisation (readmissions, emergency encounters and inpatient rehabilitation) following hip, knee and shoulder joint replacement surgery. Evidence will be generated on how these outcomes are associated with and vary according to patient, surgical, implant, hospital and pharmacological factors.&#x0D; As Australia lacks a national identifier, seven linkage agencies are probabilistically linking AOANJRR hip, knee and shoulder replacement data (1999-2017) with 20 datasets. Datasets include government-subsidised health services, procedural and prescription data. Hospital separations and emergency attendance data from Australia’s eight jurisdictions together with national cancer registry and rehabilitation service data are also planned for linkage. Linked data are maintained in a secure remote access computing environment.&#x0D; ResultsTo date, national Medicare Benefits Schedule, Pharmaceutical Benefits Scheme and the Australian Cancer Database data have been linked with &gt;900,000 AOANJRR patients, representing 607.6 million health service records (1999-2018), 467.7 million prescriptions (2002-2018) and 184,000 cancer records, respectively. Remaining linked data will be available in mid-2020. Some initial summary results across a selected range of studies will be presented.&#x0D; Conclusion / ImplicationsThis national data-linkage program will identify areas for improvement in joint replacement surgery and modifiable risk factors contributing to poor patient outcomes.