Orthopaedic Association National Joint Replacement Research Articles

THE INFLUENCE OF BEARING SURFACE ON PERIPROSTHETIC JOINT INFECTION IN TOTAL HIP ARTHROPLASTY

BackgroundIncreasing evidence suggests a link between the bearing surface used in total hip arthroplasty (THA) and the occurrence of infection. It is postulated that polyethylene has immunomodulatory effects and may influence bacterial function and survival, thereby impacting the development of periprosthetic joint infection (PJI). This study aimed to investigate the association between polyethylene type and revision surgery for PJI in THA using data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). We hypothesized that the use of XLPE would demonstrate a statistically significant reduction in revision rates due to PJI compared to N-XLPE.MethodsData from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) spanning September 1, 1999, to December 31, 2021, were used to compare the infection revision rates between THA using N-XLPE and XLPE. We calculated the Cumulative Percentage Revision rate (CPR) and Hazard Ratio (HR) while controlling for factors like age, sex, body mass index (BMI), American Society of Anesthesiologists’ (ASA) grade, and head size.ResultsFrom the total 361,083 primary THAs, 26,827 used N-XLPE and 334,256 used XLPE. Excluding data from the first 6 months post-surgery, 220 revisions occurred in the N-XLPE group and 1,055 in the XLPE group for PJI. The HR for infection revision was significantly higher in N-XLPE compared to XLPE, at 1.64 (95% CI, 1.41–1.90, p<0.001).ConclusionsThis analysis provides evidence of an association between N-XLPE and revision for infection in THA. We suspect that polyethylene wear particles contribute to the susceptibility of THA to PJI, resulting in a significantly higher risk of revision for infection in N-XLPE hips compared to those with XLPE.Level of EvidenceTherapeutic Level III.

Risk of early revision in total hip arthroplasty: the relative contribution of the surgeon versus the hospital.

Early revision for total hip arthroplasty is a serious adverse outcome. There are multiple contributing risk factors for early revision. Risk factors can exist at the level of the surgeon and the level of the institution. The primary research question of this study was to determine the relative contribution of surgeon-level and hospital-level variance to rates of early revision (overall and for infection) after primary total hip arthroplasty. This is a registry-based study from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Data for the most commonly used stem (Exeter V40) were used to reduce prosthesis variation from the analysis. A mixed effects Cox Model (also known as a frailty model) with crossed random effects for surgeon and hospital was used. Outcomes were early revision (within 2 years) for all causes and for infection. This model allowed for the risk of early revision to be explained by the variability at the surgeon level or hospital level. There were 32 031 procedures performed by 735 surgeons across 250 hospitals between 1 January 2015 and 31 December 2019. Surgeon variability significantly contributed to overall variation in revision for any cause and revision for infection (P < 0.0001). There was no significant contribution of hospital-level variation to overall revision or for infection. Surgeon-level factors play a more important role than institution-level factors in early revision after primary total hip arthroplasty. If surgeons are identified as having a higher risk of revision, there is potential for surgeon-level practice change to reduce the risk of early revision.

Collared Cementless Femoral Components Reduce the Revision Rates in Primary Total Hip Arthroplasty Using the Direct Anterior Approach: An Australian Orthopaedic Association National Joint Replacement Registry Study

BackgroundAn increased risk of periprosthetic fracture and aseptic loosening is reported when the direct anterior approach (DAA) is used for total hip arthroplasty (THA), especially with cementless implants. We assessed the rate of revision comparing collared and collarless femoral stems when using the DAA for THA. MethodsWe used data from the Australian Orthopaedic Association National Joint Replacement Registry for primary THA for osteoarthritis inserted with the DAA between January 2015 and December 2022. There were 48,567 THAs that used the DAA (26,690 collarless cementless, 10,161 collared cementless, and 11,716 cemented). Cumulative percent revision was calculated for all-cause revision, revision for periprosthetic femoral fractures, and aseptic femoral stem loosening. Cox proportional hazard ratios [HRs] were used to compare the revision of collared and collarless cementless stems. We also compared collared cementless stems and cemented stems. ResultsA higher rate of all-cause revision within 3 months of surgery was observed with collarless compared to collared cementless implants (HR: 1.99 [95% confidence interval (CI), 1.56 to 2.54]; P < .001). Similarly, collarless cementless implants were associated with a greater rate of revision for fracture in the first 6 months (HR: 2.90 [95% CI, 1.89 to 4.45]; P < .001) and after 6 months (HR 10.04 [95% CI 1.38 to 73.21]; P = .02), as well as an increased rate of revision for aseptic loosening after 2 years (HR: 5.76 [95% CI, 1.81 to 18.28], P = .003). Collared cementless and cemented stems performed similarly. ConclusionCollared stems were associated with a reduced rate of all-cause revision for cementless THA performed via the DAA. The reduction in risk may be due to protection from periprosthetic femoral fracture and aseptic loosening.

Comparable low revision rates of stemmed and stemless total anatomic shoulder arthroplasties after exclusion of metal-backed glenoid components: a collaboration between the Australian and Danish national shoulder arthroplasty registries

BackgroundThe stemmed anatomical total shoulder arthroplasty is the gold standard in the treatment of glenohumeral osteoarthritis. However, the use of stemless total shoulder arthroplasties has increased in recent years. The number of revision procedures are relatively low and therefore it has been recommended that national joint replacement registries should collaborate when comparing revision rates. Therefore, we aimed to compare the revision rates of stemmed and stemless TSA used for the diagnosis of glenohumeral osteoarthritis using data from both the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and the Danish Shoulder Arthroplasty Registry (DSR). MethodsWe included all patients who were registered in the AOANJRR and the DSR from January 1 2012 to December 2021 with an anatomical total shoulder arthroplasty used for osteoarthritis. Revision for any reason was used as the primary outcome. We used the Kaplan-Meier method to illustrate the cumulative revision rates and a multivariate cox regression model to calculate the hazard ratios. All analyses were performed separately for data from AOANJRR and DSR, and the results were then reported using a qualitative approach. Results13066 arthroplasties from AOANJRR and 2882 arthroplasties from DSR were included. The hazard ratio for revision of stemmed TSA with stemless TSA as reference, adjusted for age and gender, was 1.67 (95% CI 1.34-2.09, p<0.001) in AOANJRR and 0.57 (95% CI 0.36-0.89, p=0.014) in DSR. When including glenoid type and fixation, surface bearing (only in AOANJRR) and hospital volume in the cox regression model the hazard ratio for revision of stemmed TSA compared to stemless TSA was 1.22 (95% CI 0.85-1.75, p=0.286) in AOANJRR and 1.50 (95% CI 0.91-2.45, p=0.109) in DSR. The adjusted hazard ratio for revision of total shoulder arthroplasties with metal backed glenoid components compared to all-polyethylene glenoid components was 2.54 (95% CI 1.70-3.79, p < 0.001) in AOANJRR and 4.1 (95% CI 1.92-8.58, p<0.001) in DSR. ConclusionBased on data from two national shoulder arthroplasty registries, we found no significant difference in risk of revision between stemmed and stemless total shoulder arthroplasties after adjusting for the type of glenoid component. We advocate that metal-backed glenoid components should be used with caution and not on a routine basis.

Hip-specific and generic patient-reported outcome measure scores after primary hip replacement are associated with early revision surgery: a national registry study

BackgroundThe ability to efficiently identify patients at higher risk of poor outcomes after joint replacement would enable limited resources for post-operative follow-up to be directed to those with the greatest clinical need. This is particularly important as joint replacement rates continue to grow internationally, stretching health system capabilities. Patient-reported outcome measures (PROMs) are routinely administered in many settings and offer an opportunity to detect suboptimal patient outcomes early. This study aimed to determine whether hip-specific and generic PROM scores are associated with early revision hip replacement within six to 24 months after the primary procedure.MethodsPre-operative and six-month post-operative PROM scores for patients undergoing primary total hip replacement (THR) were obtained from the Australian Orthopaedic Association National Joint Replacement Registry and Arthroplasty Clinical Outcomes Registry National and linked to revision surgery data. Clinically important improvement was defined using anchor-based thresholds. Associations between PROM scores (hip pain, Oxford Hip Score, HOOS-12, EQ-5D-5L, EQ VAS, patient-perceived change, satisfaction) and revision surgery were evaluated using t-tests, chi-square tests and regression models.ResultsData were analysed for 21,236 primary THR procedures between 2013 and 2022. Eighty-eight revision procedures were performed at six to 24 months. Patients who were revised had more back pain and worse HOOS-12 scores pre-operatively but between-group differences were small. Worse post-operative PROM scores (hip pain, Oxford, HOOS-12, EQ-5D-5L, EQ VAS) were associated with early revision, after adjusting for age and sex (p < 0.001 for all analyses). Patient dissatisfaction (relative risk (RR) 10.18, 95%CI 6.01–17.25) and patient-perceived worsening (RR 19.62, 95%CI 11.33–33.98) were also associated with a higher likelihood of revision. Patients who did not achieve clinically important improvement in hip pain, function, or quality of life had a higher revision risk (RRs 2.54–5.64), compared with those who did (reference).ConclusionSix-month hip-specific and generic PROM scores can identify patients at higher risk of early revision surgery. Our data highlight the utility of routine post-operative PROM assessment for signaling suboptimal surgical outcomes.

Trends in the use of ankle arthrodesis and total ankle replacements in Australia over the past 20years.

End stage ankle osteoarthritis (OA) is debilitating. Surgical management consists of either ankle arthrodesis (AA) or a total ankle replacement (TAR). The purpose of this study is to assess the trends in operative intervention for end stage ankle OA in an Australian population. This is a retrospective epidemiological study of 15,046 surgeries. Data were collected from publicly available national registries including the Australian Medicare Database and Australian Orthopaedic Association National Joint Replacement Registrar from 2001 to 2020. There was a significant increase in all ankle surgeries performed across the period of interest. AA remained the more commonly performed procedure throughout the course of the study (11,946 cases, 79.4%) and was never surpassed by TAR (3100, 20.6%). The overall proportions demonstrated no significant changes from 2001 to 2020. The incidence of ankle surgeries continues to increase with the ageing and increasingly comorbid population of Australia. Despite demonstrating no significant overall change in the ratio of TAR and AA in our study population and period, there are noticeable trends within the timeframe, with a recent surge favouring TAR in the last 5years.

Characteristics associated with rerevision of primary inlay and onlay reverse shoulder arthroplasty. Analysis from the Australian Orthopaedic Association National Joint Replacement Registry

BackgroundTwo designs of primary reverse total shoulder arthroplasty (rTSA), inlay reverse total shoulder arthroplasty (in-rTSA) and onlay reverse total shoulder arthroplasty (on-rTSA) that had undergone an aseptic revision were compared to determine differences in the rate of rerevision. MethodsIn this comparative observational national registry study between January 1, 2012, and December 31, 2021, all rTSA utilizing either a modular inlay or onlay metaphyseal humeral component that had been revised for aseptic reasons formed 2 cohort groups. The cumulative percentage rerevision (2nd CPR) was determined using Kaplan-Meier estimates of survivorship and hazard ratios (HRs) from Cox proportional hazard models adjusted for age and sex. A minor category revision involved exchange of parts not fixed to bone whilst major revisions did. The primary and revision diagnoses, surgeon primary volume experience, and revision category were compared. Shoulder Modular Replacement (SMR)/SMR L1 or L2 combination (Lima Corporate, San Daniele del Friuli, Italy) was excluded at subanalysis. ResultsThe 2nd CPR at 3 years was 20.4% (95% confidence interval 17.1, 24.1) for in-rTSA (n = 571) and 16.1%(11.6, 22.2) for on-rTSA (n = 249). The risk of rerevision was not different between the 2 cohort groups. Primary diagnosis fracture was associated with an increased risk of rerevision for on-rTSA (entire period on-rTSA HR = 3.16(1.50, 6.68), P = .002), and in-rTSA at subanalysis (entire period on-rTSA HR = 2.91(1.33, 6.33), P = .007). 59.9% of in-rTSA and 24.1% of on-rTSA aseptic revisions were minor. The revision diagnosis, the surgical experience of rTSA and if the revision was major or minor did not change the rate of rerevision. The most common reason for both in-rTSA (50%) and (43.2%) on-rTSA rerevision was instability/dislocation. DiscussionRerevision rates of in-rTSA and on-rTSA after aseptic revision are high. The primary rather the revision diagnosis changed rerevision rates in contemporary rTSA surgery. Minor revisions did not reduce rerevision rates for in-rTSA or on-rTSA compared to humeral/glenoid revision. Increased surgical experience of primary rTSA did not change the rate of rerevision of in-rTSA or on-rTSA.

Registry-based study of survivorship of cemented femoral components versus collared cementless femoral components in total hip arthroplasty in older patients with osteoarthritis.

In recent years, the use of a collared cementless femoral prosthesis has risen in popularity. The design intention of collared components is to transfer some load to the resected femoral calcar and prevent implant subsidence within the cancellous bone of the metaphysis. Conversely, the load transfer for a cemented femoral prosthesis depends on the cement-component and cement-bone interface interaction. The aim of our study was to compare the three most commonly used collared cementless components and the three most commonly used tapered polished cemented components in patients aged ≥ 75 years who have undergone a primary total hip arthroplasty (THA) for osteoarthritis (OA). Data from the Australian Orthopaedic Association National Joint Replacement Registry from 1 September 1999 to 31 December 2022 were analyzed. Collared cementless femoral components and cemented components were identified, and the three most commonly used components in each group were analyzed. We identified a total of 11,278 collared cementless components and 47,835 cemented components. Hazard ratios (HRs) from Cox proportional hazards models, adjusting for age and sex, were obtained to compare the revision rates between the groups. From six months postoperatively onwards, patients aged ≥ 75 years undergoing primary THA with primary diagnosis of OA have a lower risk of all-cause revision with collared cementless components than with a polished tapered cemented component (HR 0.78 (95% confidence interval 0.64 to 0.96); p = 0.018). There is no difference in revision rate prior to six months. Patients aged ≥ 75 years with a primary diagnosis of OA have a significantly lower rate of revision with the most common collared cementless femoral component, compared with the most common polished tapered cemented components from six months postoperatively onwards. The lower revision rate is largely due to a reduction in revisions for fracture and infection.

Measurement Properties of the Oxford Shoulder Score and Minimal Clinically Important Changes After Primary Total Shoulder Replacement Surgery.

We evaluated the measurement properties of the Oxford Shoulder Score (OSS) and estimated the minimal clinically important change (MCIC) in patients undergoing primary total shoulder replacement in Australia. Deidentified data from the Australian Orthopaedic Association National Joint Replacement Registry were used for this analysis. Pre- and 6-month postoperative OSS scores were used, with the 5-level EuroQoL quality of life instrument and shoulder pain scores used as comparators. Floor and ceiling effects, internal consistency reliability, construct validity, and responsiveness to change were evaluated using standard psychometric methods. Mean change and predictive modeling approaches (with and without adjustment for the proportion of improved patients) were used to calculate MCIC thresholds, with patient-perceived improvement after surgery as the anchor. Preoperative OSS data were available for 1,117 patients (59% female; 90% aged ≥60 years) undergoing primary total shoulder replacement. No floor or ceiling effects were observed pre- or postoperatively. The OSS showed high internal consistency reliability (Cronbach alpha >0.89), good construct validity, and high responsiveness to change (effect size 1.88). The MCIC derived from the mean change method was 6.50 points (95% confidence interval [95% CI] 4.41-8.61). The predictive modeling approach produced an MCIC estimate of 8.42 points (95% CI 5.68-12.23) after adjustment. The OSS has good measurement properties to capture pain and function outcomes after shoulder replacement procedures and is highly responsive to change. Based on robust methods, an increase in OSS scores of at least eight points can be considered as meaningful improvement after surgery from the patient's perspective.

Increasing Use of Total Wrist Arthroplasty-An Australian National Joint Registry Report.

Background and Purpose There is limited literature reporting the long-term results and outcomes of total wrist arthroplasty (TWA). The aim of this study was to describe the incidence, usage, and survival of wrist arthroplasty using data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Methods Data included all primary TWA procedures from 2006 to 2021. The primary outcome assessed was revision surgery. Utilization of TWA, etiology leading to TWA, patient demographics, and surgical factors were also assessed. Results There were 439 primary TWA procedures performed across the 16-year reporting period. Four prostheses (Motec, Universal 2, Freedom, and ReMotion) have been used, with a recent increased usage toward the Motec, which accounted for 97.4% of prostheses implanted in 2021. There has also been an increase in the number of surgeons performing TWA over time. The most common underlying etiology was osteoarthritis (72.7%), followed by rheumatoid arthritis (15.9%). Implantation for inflammatory arthropathy remained relatively constant across time; however, TWA has been utilized with increasing frequency for the treatment of osteoarthritis and other indications more recently. The cumulative percent revision at 10 years was 18.3%. Loosening accounted for 25.6% of all revisions, followed by osteolysis (12.8%), pain (12.8%), and instability (7.7%). Attempted conversion to an arthrodesis occurred in 10.3% of all revisions. Conclusion There has been an increase in both the volume of TWA performed and the number of surgeons undertaking this procedure in Australia over the past 16 years. The Motec system has become the prosthesis of choice. Medium-term revision rates are inferior when compared with Australian data for hip, knee, and shoulder arthroplasty.

Utilizing Stems in Primary Total Knee Arthroplasty: Analysis of the Australian Orthopaedic Association National Joint Replacement Registry Data

BackgroundWe compared revision rates and reasons for revision for primary total knee arthroplasty (TKA) performed for osteoarthritis with and without tibial stem extensions. MethodsData from the Australian Orthopaedic Association National Joint Replacement Registry were used to compare all-cause revision, reason, and type of revision between primary TKA using stemmed tibial prostheses and non-stemmed prostheses. ResultsAll-cause revision for TKA with stem extension was higher for the first 6 months (hazard ratio [HR] 1.47; 95% confidence interval [CI]1.19 to 1.82; P < .001); while after 1.5 years TKA with stem extension had a lower rate of revision (HR 0.84; 95% CI 0.73 to 0.97; P = .01). Stemmed components were more likely to be revised for infection between 3 months and 1.5 years after surgery (HR 1.39; 95% CI 1.05 to 1.83; P = .02). The revision rate for aseptic loosening was lower in the stemmed group beyond 2 years (HR = 0.45; 95% CI 0.31 to 0.63; P < .001). Insert-only revision was higher in the stemmed group at all times (HR = 1.42; 95% CI 1.21 to 1.66, P < .001). Isolated tibial component revision was lower in the stemmed group at all times (HR 0.47; 95% CI 0.29 to 0.74; P = .001). Aseptic loosening for tibial component-only revision was significantly lower in the stemmed group at all times (HR 0.23; 95% CI 0.11 to 0.50; P < .001). ConclusionsPatients undergoing primary stemmed TKA have lower rates of all-cause revision beyond 1.5 years and tibial component-only revision at all times. Further investigation is required to preoperatively select patients that benefit from augmentation with stems.

What is the most appropriate comparator group to use in assessing the performance of primary total hip prostheses within the community?

There are variations in the performance of individual prostheses used in hip replacements. Some of which have unexpectedly higher revision rates - outliers. The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) has established a standardised multi-stage approach for identifying these devices. This is done by comparing the revision rates of individual prostheses to all other prostheses in class, with the exception of large head metal-on-metal (LHMoM) prostheses. However, improvements in device design and performance over time have required a need to reconsider the comparator group. This study aimed to identify a more specific comparator to better reflect contemporary surgical practice. The time to first revision was estimated on the data of 413,417 primary total conventional hip replacements undertaken for osteoarthritis (OA) from 01 January 2003 to 31 December 2019. Survivorship analyses with stepwise exclusions were undertaken. The first exclusion was LHMoM, followed by other non-modern bearing surfaces (defined as all the bearing couples except metal or ceramic heads on cross-linked polyethylene and mixed ceramic-on-ceramic), and then devices with modular neck-stem design or used for specific purposes (incl. constrained, dual-mobility, and head size <28 mm). Lastly, all remaining prostheses previously identified as having a higher than anticipated rate of revision (HTARR) were also excluded. These exclusions progressively reduced the cumulative percent revision (CPR) rate. The final comparator, which only includes satisfactory-performed prostheses of contemporary design and use, has a 10-year CPR of 4.30% (95% CI, 4.2-4.41) which is lower than 4.93% (95% CI, 4.84-5.02) for the current comparator used by the AOANJRR (all prostheses excluding LHMOM). Over the study period, 13 additional components were identified utilising the modified comparator. The calculation of the comparator revision rate should be re-evaluated to include only modern prosthesis constructs to ensure that poorly performing prostheses are identified early.

National Registry Data Analysis on a Unique Highly-Crosslinked Polyethylene for Total Hip Arthroplasty

BackgroundSeveral types of highly-crosslinked polyethylene with different manufacturing processes and mechanical properties are commercially available, including HIGHCROSS (Medacta). The aim of this registry study is to ascertain the long-term safety of the HIGHCROSS liners in total hip arthroplasty and compare the revision rates with its contemporaries using real-world data to establish their safety and generalizability when used by multiple surgeons. MethodsThe Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and the Swiss National Joint Registry (SIRIS) were selected for the large number of users of Medacta implants and the availability of long-term results. Three reports from SIRIS and 4 reports from AOANJRR were examined to establish the overall and Kaplan-Meier (KM) cumulative revision rate. ResultsAccording to SIRIS, the HIGHCROSS liner was the most commonly used bearing surface with Medacta stems with overall revision rates for wear/osteolysis at 9.7 years of 0.04% and 0.03%, respectively, for AMIStem and Quadra. Based on AOANJRR, the KM cumulative revision rate for any reason of Medacta stems with HIGHCROSS liners was lower than that with ceramic liners at 3 years for MasterLoc and at 10 years for Quadra. The KM cumulative revision rate for any reasons of Medacta cementless cups with HIGHCROSS liners at 12 years was lower than the comparator made of all other implants and tribological couplings (1.6% vs 2.1%). ConclusionsThis real-world data proves that long-term HIGHCROSS survival rates are comparable to other modern bearing surfaces.

A Polished Cobalt-Chrome Baseplate is not Associated With a Lower Revision Rate Than Matt Titanium in a Single Total Knee Arthroplasty Implant System With Identical Baseplate Design

BackgroundPolished baseplates were introduced into total knee arthroplasty (TKA) systems to reduce the incidence of backside wear. In 2004, a fixed-bearing knee arthroplasty system underwent a change in baseplate material from matt titanium to polished cobalt-chrome (CoCr) with the intention to reduce backside wear. Other design aspects were left unchanged. The aim of this study was to compare these implants with each baseplate using data from the Australian Orthopaedic Association National Joint Replacement Registry. MethodsPrimary TKA procedures performed between January 2010 and December 2021 for osteoarthritis, using a single design with cross-linked polyethylene inserts and matt titanium or polished CoCr baseplates, were analyzed. The primary outcome was all-cause revision, summarized using Kaplan-Meier estimates, with age- and sex-adjusted hazard ratios estimated from Cox proportional hazards models. In total, there were 2,091 procedures with matt titanium and 2,519 procedures with polished CoCr baseplates. ResultsThe 9-year cumulative percent revision was 2.5% (95% confidence interval [CI] 1.8 to 3.5%) and 4.2% (95% CI 3.1 to 5.6%) for the matt titanium and CoCr groups, respectively. Compared to matt titanium, the revision rate of CoCr baseplates was not significantly higher (hazard ratio 1.44; 95% CI 0.96 to 2.15; P = .076). ConclusionsPolished CoCr baseplates in a single TKA system were not associated with reduced all-cause revision rates compared to matt titanium up to 11 years post-TKA. Our results suggest that the predicted reduction in wear particle debris production from polished CoCr baseplates may not correlate with reduced revision rates in vivo, but further evaluation is required.

Survivorship of shoulder arthroplasty in young patients with osteoarthritis: an analysis of the Australian Orthopaedic Association National Joint Replacement Registry.

The treatment of shoulder osteoarthritis in the young patient remains challenging. The higher functional demands and higher expectations of the young patient cohort are often coupled with increased failure and revision rates. Consequently, shoulder surgeons are faced with a unique challenge with implant selection. The aim of this study was to compare the survivorship and reasons for revision of 5 classes of shoulder arthroplasty in patients aged <55 years with a primary diagnosis of osteoarthritis by use of data from a large national arthroplasty registry. The study population included all primary shoulder arthroplasty procedures undertaken for osteoarthritis in patients aged <55 years and reported to the registry between September 1999 and December 2021. Procedures were grouped into the following classes: total shoulder arthroplasty (TSA), hemiarthroplasty resurfacing (HRA), hemiarthroplasty stemmed metallic head (HSMH), hemiarthroplasty stemmed pyrocarbon head (HSPH), and reverse total shoulder arthroplasty (RTSA). The outcome measure was the cumulative percent revision, which was defined using Kaplan-Meier estimates of survivorship to describe the time to the first revision. Hazard ratios (HRs) were calculated from Cox proportional hazards models, adjusting for age and sex, to compare revision rates among groups. There were 1564 shoulder arthroplasty procedures in patients aged <55 years, of which 361 (23.1%) were HRA, 70 (4.5%) were HSMH, 159 (10.2%) were HSPH, 714 (45.7%) were TSA, and 260 (16.6%) were RTSA. HRA had a higher rate of revision than RTSA after 1 year (HRA = 2.51 (95% CI 1.30, 4.83), P=.005), with no difference prior to that time. In addition, HSMH had a higher rate of revision than RTSA for the entire period (HR,2.69 [95% confidence interval, 1.28-5.63], P=.008). There was no significant difference in the rate of revision for HSPH and TSA when they were compared with RTSA. Glenoid erosion was the most common cause of revision for HRA (28.6% of revisions) and HSMH (50%). Instability/dislocation was the leading cause of revision for RTSA (41.7%) and HSPH (28.6%), and for TSA, the majority of revisions were for either instability/dislocation (20.6%) or loosening (18.6%). These results should be interpreted within the context of the lack of availability of long-term data on RTSA and HSPH stems. RTSA outperforms all implants regarding revision rates at mid-term follow-up. The high early dislocation rate associated with RTSA, as well as the lack of revision options available to address this, indicates that careful selection of patients and a greater appreciation of anatomic risk factors are needed in the future.

Fixed Bearing in Primary Total Ankle Replacement Is Associated with Reduced Revision Rates

Category: Ankle Arthritis; Ankle Introduction/Purpose: The revision rate for total ankle replacement (TAR) in Australia has decreased over the past 6-years, coinciding with an increased use in fixed bearing prostheses. This study aimed to determine if the use of fixed bearing prostheses or surface coating are associated with lower revision rates. Methods: Data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) included primary cementless TAR procedures performed for any diagnosis from January 2015-December 2021. Procedures were grouped by insert mobility (fixed &amp; mobile) and surface coating (HA &amp; non HA). The time to first revision was summarised using Kaplan-Meier estimates of survivorship, with hazard ratios (HR) obtained from Cox proportional hazards models including age, gender, insert mobility and surface coating. Results: There were 1,865 primary cementless TAR procedures of which 1,467 (78.7%) were fixed bearing and 398 (21.3%) mobile bearing. HA coating was used in 422 (28.8%) of fixed bearing procedures and 336 (84.4%) of mobile bearings. The cumulative percent revision (CPR) at 6 years was 4.1% for fixed bearing and 9.8% for mobile bearing TAR procedures. When the effects of insert mobility and bearing surface were considered separately, fixed bearings had a significantly lower revision rate compared to mobile bearings (HR=0.48), but there was no significant difference between HA and non HA coatings (HR = 1.18). When analysed by insert mobility and surface coating, mobile bearing HA prostheses had a significantly higher revision rate than fixed bearing prostheses with either coating. Conclusion: Analysis of 1,865 primary cementless TAR procedures shows that fixed bearing prostheses have significantly lower rates of revision than mobile bearing prostheses even when adjusting for surface coating.

Forecasting the future burden of primary total shoulder replacement in Australia

To forecast the number of primary total shoulder replacements (TSR) in Australia to the year 2035, and associated costs. De-identified TSR data for 2009-2019 were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. Population data, including population projections to 2035, were obtained from the Australian Bureau of Statistics. Three forecasting scenarios were used: constant TSR rates from 2019 onwards (Scenario 1, conservative); continued growth in TSR rates using negative binomial regression (Scenario 2, exponential); and continued growth using negative binomial regression with monotone B-splines (Scenario 3, moderate). Healthcare costs were estimated using TSR projections and average procedure costs, inflated to 2035 Australian dollars. The use of TSR increased by 242% in Australia from 2009 to 2019 (from 1983 to 6789 procedures for people ≥40 years). Under Scenario 1, the incidence of TSR is conservatively projected to rise to 9676 procedures by 2035 (43% increase from 2019), at a cost of $AUD 312.6 million to the health system. Under Scenario 2, TSR incidence would increase to 45,295 procedures by 2035 (567% increase), costing $AUD 1.46 billion. Under Scenario 3, 28,257 TSR procedures are forecast in 2035 (316% increase) at a cost of $913 million. Recent growth in TSR likely relates to prosthesis improvements, greater surgeon proficiency, and expanded clinical indications. Under moderate and exponential scenarios that consider rising TSR rates and population projections, Australia would face three- to five-fold growth in procedures by 2035. This would have profound implications for the healthcare budget, clinical workforce, and infrastructure.

Distal humeral hemiarthroplasty compared to total elbow replacement for distal humeral fractures: a registry analysis of 906 procedures

Total elbow replacement (TER) is an accepted treatment for complex intra-articular distal humerus fractures in elderly patients. Distal humeral hemiarthroplasty (HA) is also a potential surgical option for unreconstructable fractures and avoids the concerns regarding mechanical wear and functional restrictions associated with TER. In the current literature, there are limited data available to compare the revision rates of HA and TER for the treatment of fracture. We used data from a large national arthroplasty registry to compare the outcome of HA and TER undertaken for fracture/dislocation and to assess the impact of demographics and implant choice on revision rates. Data obtained from the Australian Orthopaedic Association National Joint Replacement Registry from May 2, 2005, to December 31, 2021, included all procedures for primary elbow replacement with primary diagnosis of fracture/dislocation. The analyses were performed using Kaplan-Meier estimates of survivorship and hazard ratios from Cox proportional hazards models. There were 293 primary HA and 631 primary TER procedures included. The cumulative percent revision (CPR) rate at 9 years was 9.7% for HA (95% confidence interval [CI] 6.0, 15.7), and 11.9% (95% CI 8.5, 16.6) for TER. When adjusted for age and gender, there was a significantly higher risk of revision after 3 months for TER compared to HA (HR=2.47 [95% CI 1.22, 5.03], p=0.012). There was no difference in the rate of revision for patients aged <55 years or ≥75 years when HA and TER procedures were compared. In primary TER procedures, loosening was the most common cause of revision (3.6% of primary TER procedures) and the most common type of revision in primary TER involved revision of the humeral component only (2.6% of TER procedures). TER has a higher rate of 1st revision for loosening compared to HA (HR=4.21(1.29, 13.73); p=0.017). In HA procedures instability (1.7%) was the most common cause for revision. The addition of an ulna component was the most common type of revision (2.4% of all HA procedures). For the treatment of distal humerus fractures, HA had a lower revision rate than TER after 3 months when adjusted for age and gender. Age <55 or ≥75 years was not a risk factor for revision when HA is compared to TER. Loosening leading to revision is more prevalent in TER and increases with time. In HA, the most common type of revision involved addition of an ulna component with preservation of the humeral component.

Does hospital setting influence shoulder replacement revision rate? A national comparison of outcomes between private and public settings.

Australian healthcare relies on both private and public sectors to meet the demand for surgical care. Rapid growth of shoulder replacement surgery highlights a disparity in service provision, with two-thirds occurring privately. This study aimed to assess the influence of hospital setting on shoulder replacement revision rate at a national level. All primary shoulder replacements recorded by the Australian Orthopaedic Association National Joint Replacement Registry from April 2004 to December 2020 were included. Private and public settings were compared for stemmed total shoulder replacement (sTSR) for osteoarthritis (OA), reverse total shoulder replacement (rTSR) for OA/cuff arthropathy (CA), and rTSR for fracture. The primary outcome was cumulative percent revision (CPR), with Kaplan-Meier estimates of survivorship to determine differences between private and public hospitals, recorded as hazard ratios (HR). Secondary analyses investigated differences between hospital settings, targeting hospital outliers for revision and prosthesis selection. Primary sTSR (OA) demonstrated a higher revision rate in private hospitals compared to public hospitals (HR = 1.27; P = 0.001), as did rTSR (OA/CA) after 3 months (HR = 1.33; P = 0.003). However, no significant difference was observed for primary rTSR (fracture) (HR = 1.10; P = 0.484). Restricting rTSR (OA/CA) to the best performing prosthesis combinations eliminated the difference between private and public outcomes (HR 1.10; P = 0.415). No other secondary analysis altered the primary result. Differences exist between private and public hospitals for revision rate following primary shoulder replacement. Prosthesis selection accounts for some of the variation. Further analysis into patient specific characteristics is necessary to better understand these disparities.

Short-stem hip arthroplasty in Australia and the Netherlands: a comparison of 12,680 cases between the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and the Dutch Arthroplasty Register (LROI).

We compared the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and the Dutch Arthroplasty Register (LROI) regarding patient, prosthesis, and procedure characteristics as well as revision rates for uncemented short-stem total hip arthroplasties (THAs). All THAs with an uncemented short-stemmed femoral component performed between 2009 and 2021 were included from the AOANJRR (n = 9,328) and the LROI (n = 3,352). Kaplan-Meier survival analyses and multivariable Schemper's weighted Cox regression analyses with data from 2009-2021 and 2015-2021 were performed with overall revision as endpoint. In Australia, the proportion of male patients (51% vs. 40%), patients with ASA III-IV score (30% vs. 3.7%), BMI ≥ 30.0 (39% vs. 19%), and femoral heads of 36 mm (58% vs. 20%) were higher than in the Netherlands. Short-stem THAs in Australia and the Netherlands had comparable 10-year revision rates (3.4%, 95% confidence interval [CI] 2.9-4.0 vs. 4.8%, CI 3.7-6.3). Multivariable Cox regression analyses with data from 2009-2021 showed a higher risk for revision of short-stem THAs performed in the Netherlands (HR 1.8, CI 1.1-2.8), whereas the risk for revision was comparable (HR 0.9, CI 0.5-1.7) when adjusted for more potential confounders using data from 2015-2021. Short-stem THAs in Australia and the Netherlands have similar crude and adjusted revision rates, which are acceptable at 10 years of follow-up.