The value of joint registries is to (1) provide large scale longitudinal follow-up of classes of implants and individual implants—thereby providing potential for improved performance—and (2) serve as a tripwire for unexpected problem implants which is well appreciated. The purpose of this talk is not to reiterate the value of joint arthroplasty registries, but rather to look at several key findings from joint registries around the world and discuss what these mean for orthopaedic surgery today. Observation #1: Registries can tell us where the biggest problems are so we can act on them: Example: Early failures—those occurring in the first two years—account for about half of all failures by ten years. Early failures consist of mainly technically related problems and infections. If we can reduce these problems, we can reduce the number of patients having a second surgery after joint replacement by almost half. For one type of early failure (infection), the registry data show rate of infection after THA and TKA has not declined substantially in the last 20 years. We need major innovation in this area to solve this problem. On the other hand, registry data show early failures in older patients after THA are often due to periprosthetic femur fracture: we can solve this problem now with choice of stem fixation or prophylactic wires in high risk patients. Observation #2: Innovation can and does work! It is not correct to suggest that no new implants have led to improved results. Example: Registry data demonstrate that cross-linked polyethylene bearings have reduced the risk of revision after THA dramatically, especially in younger patients. Observation #3: Gathering more detailed information, such as patient reported outcomes, at least on limited samples of patients, can provide further insights. Example: Registry data demonstrate much greater variability in clinical outcomes of TKA in younger patients compared to older patients. Observation #4: Having national registries from different countries provides synergistic information. Example: Combining data from several national registries provides information on performance of femoral heads of different diameter and material that are not available from just one source. Observation #5: Registries may provide unexpected information that opens unexpected avenues for study. Example: Several registries demonstrate men have a 1.5–2 times higher risk of infection after TKA. We did not know this before. Why is this? Can we reduce it?

Background: Fracture neck of the femur (NOF) is one of the indications for Total Hip Replacement (THR). However, the practice is not the same throughout the world. Aim: We compared the use of THR in the management of the fracture NOF using the annual reports of the National Joint Registries from various countries. Material and Methods: We used the latest available on line annual report of seven national arthroplasty registries to ascertain the rate of use of THR for fractures of the neck of the femur. The registries from Australia, Canada, Norway, Sweden, and the UK gave a detailed breakup of the indications for THR in their reports. Results: 11.9% of the all the THRs performed in Norway since 1987 were for NOFs. · 11.39% of all the THRs performed in Sweden since 1992 were for NOFs. 6.0% of the THRs performed in Canada in 2002–2003 were for NOFs. 2.9% of THRs performed in Australia since 1999 were for NOFs. 1.9% of the THRs performed in the UK in the period April – December 2003 were for NOFs. The registries from Finland and New Zealand had no detailed information on their websites regarding the indications for THA surgery. Discussion: In the Scandinavian countries, THR is performed for the management of a NOF 6 times more often than in the UK, and 4 times more often than in Australia. It is unlikely that the prevalence of patients with previous osteoarthritis of hip who sustain a NOF is higher in the Scandinavian countries than in the UK. Women in Sweden have a higher lifetime risk of hip fracture and live longer, so a procedure providing a good long term results would be beneficial. Provision of health care may also influence surgical management options. The long waiting lists for elective THR in the UK may explain the low number of THRs performed for NOFs

Abstract

The most recent Australian registry has a database of 547,407 knee arthroplasties, having added over 52,000 in 2016. Total knee arthroplasties (TKA) comprise 83.8%, revisions (RevTKA) 8.1% and “partials of all types” 8.1%. Since 2003, the percent of TKA has increased from 76.7%, RevTKA has stayed stable and partial replacements have declined from 14.5%. In the last year, however, TKA declined slightly.

There is a slightly higher percentage of women (56.1%) undergoing TKA and this has remained very stable since 2003. Revision rates are slightly higher for men. Percentages of the youngest (<55) and oldest (>85) are small and stable. The 75–84 year olds have declined as 55–74 year olds have increased. This represents a gradual shift to earlier TKA surgery. More patella are resurfaced and this is a gradual trend with a cross over in 2010 when half were resurfaced. Computer navigation is progressively more popular and now accounts for almost 30% of cases. Cement fixation is also increasing and accounts for about 65% of cases. Crosslinked polyethylene is gradually replacing non crosslinked and in 2014 was used in 50% of cases.

Revisions are performed most commonly for loosening and infection. Revision rates correlate directly with age. Loosening is the most common indication for revision in both genders, but males have a distinctly higher revision rate due to infection. Revision rates are slightly higher in all forms of mobile bearing than fixed bearing.

Minimally constrained (cruciate retaining) devices are used in the majority of TKAs. Posterior stabilised implants are in slight decline, having peaked in about 2008–2010. Minimally constrained implants are in slight decline as medial pivot/medial congruent devices have been used more frequently. Revision rates are similar amongst all three implant types: PS implants are revised at a slightly higher rate. When an early Medial Pivot (MP) implant is excluded the newer version has better results. The reasons for revision are similar amongst all 3 groups with slightly higher loosening rates for PS designs. (Could this represent backside wear with older locking mechanisms, surface finish and non crosslinked poly?) The MP designs had slightly higher revision rates for “pain”, which is not recognised as a reasonable indication for revision.

Revision rates are steadily higher for TKAs without patella resurfacing over 16 years, but the questions as to whether: i. the surgeries were secondary resurfacings or full revisions or ii. if secondary resurfacings eliminated pain are unknown. The combinations at greatest risk of revision were a posterior stabilised or medial pivot arthroplasty without patellar resurfacing. Cementless fixation leads to a higher revision rate.

If age and computer navigation are evaluated in terms of revision rates, young patients with and without computer navigated arthroplasties failed at the highest rates, distinct from patients >65. However, if failure rates due only to loosening are evaluated, then computer navigation leads to a lower revision rate in the <65 group. This has been interpreted as the protective effect of better component position that only shows up in patients who use the arthroplasty more aggressively.

Patient specific instrumentation (PSI) or Individual Designed Instrumentation (IDI) were revised at marginally higher rates than conventional instrumentation. Crosslinked polyethylene appears to be superior at 12 years (CRR= 4%) versus non crosslinked polyethylene (CRR>7%). This is the result of fewer failures due to loosening with crosslinked poly. The superiority of crosslinked poly was greater in the younger, more active patient.

Background

Since the development of modern total hip replacement (THR) more than 50 years ago, thousands of devices have been developed in attempt to improve patient outcomes and prolong implant survival. Modern THR devices are often broadly classified according to their method of fixation; cemented, uncemented or hybrid (typically an uncemented acetabular component with a cemented stem). Due to early failures of THR in young active patients, the concept of hip resurfacing was revisited in the 1990's and numerous prostheses were developed to serve this patient cohort, some with excellent clinical results. Experience with metal-on-metal (MoM) bearing related issues particularly involving the ASR (DePuy Synthes, Warsaw, Indiana) precipitated a fall in the use of hip resurfacing (HR) prostheses in Australia from a peak of 30.2% in 2004 to 4.3% in 2015. The effects of poorly performing prostheses and what is now recognised as suboptimal patient selection are reflected in the AOANJRR cumulative percent revision (CPR) data which demonstrates 13.2% revision at 15 years for all resurfacing hip replacements combined; with 11 different types of hip resurfacing prostheses recorded for patients less than 55 years of age and a primary diagnosis of OA. When this data is restricted to only those prostheses currently used in Australia (BHR; Smith and Nephew, Birmingham, UK & ADEPT; MatOrtho Ltd, Surrey, UK) there is a CPR of 9.5% at 15 years for all patients. Despite these CPR results, recognition is emerging of the important distinction between MoM THR and resurfacing.

Furthermore, in light of current consensus for patient selection and the surgical indications for resurfacing, a gender analysis demonstrates a CPR for females of 14.5% at 10 years compared to 3.7% for males. Similar difference for head size >50mm with 6% CPR at 10 years compared to 17.6% for head size <50mm (HR=2.15; 1.76, 2.63; p<0.001). Leading to renewed interest in resurfacing particularly in the young, active male. In addition to registry based CPR data, several studies have concluded that a true difference in mortality rates between HR and other forms of THR exists independent of age, sex or other confounding factors. We hypothesised that a difference in adjusted mortality rates between HR and other forms of THR may also be present in the Australian population.

We undertook an ad hoc data report request to the AOANJRR. The data set provided was deidentified for patient, surgeon and institution and included all HR and conventional THR procedures performed for the diagnosis of primary osteoarthritis recorded in the Registry since inception in 1999. We requested mortality and yearly cumulative percent survival (CPS) of patients for primary HR and THR with sub-group analysis by the mode of fixation.

There were 12,910 hip resurfacings (79% male) compared to 234,484 conventional THR (46.8% male) over the study period. When adjusted for age and gender over the 15 years of available data, there was a statistically significant difference in cumulative percent survival (CPS) between conventional THR and hip resurfacing (HR 1.66 (1.52, 1.82; p<0.001)) and between cemented THR and hip resurfacing (HR 1.96 (1.78, 2.43; p<0.001)); between uncemented THR and hip resurfacing (HR 1.58 (1.45, 1.73; p<0.001)); and between hybrid THR and hip resurfacing (HR 1.82 (1.66, 1.99; p<0.001)). When adjusted for age, gender and ASA over the 3 years data available, there was no statistically significant difference in CPS between hip resurfacing and any individual fixation type of THR.

Short-stem total hip arthroplasty (THA) may have bone sparing properties, which could be advantageous in a younger population with high risk of future revision surgery. We used data from the AOANJRR, LROI and SAR to compare survival rates of primary THA, stems used in the first-time revision procedures as well as the overall survival of first-time revisions between a cohort of short-stem and standard-stem THA.

Short-stem THAs (designed as a short stem with mainly metaphyseal fixation) between 2007 and 2021 were identified (n=16,258). A propensity score matched cohort (1:2) with standard THAs in each register was identified (n=32,515). The cohorts were merged into a research dataset. Overall survival at 12 years follow-up was calculated using Kaplan-Meier survival analyses. Stem revisions (short-stem THA n=239, standard-stem THA n=352) were identified. The type of revision stem was classified as standard (<160 mm) or long (>160 mm). The survival rate of all first-time revisions in the two groups was calculated using any type of revision as outcome.

The 12 year- overall survival rate (all revisions, all causes) for primary short-stem THAs was 95.3% (CI 94.5–95.9%), which was comparable to 95.2% (CI 94.7–95.7%) for standard-stem THAs. In the short-stem THA group, a standard stem (<160 mm) was more often (59%) used in the first-time revision than in the standard-stem group (47%, p=0.004). The overall survival of the first-time revisions did not differ between cases primarily operated with a short or a standard stem.

In our multi-national register study, the overall survival rate of short stems was similar to that of standard stems. In short stem revisions there was a higher likelihood of using a standard-length stem for the revision compared with first-time revisions of standard stems. This finding might indicate bone-sparing properties with short-stemmed THAs.

Introduction and Aims: Nine countries have established national joint replacement registries. The first population-based national registry, the Swedish Knee Registry, was established in 1975 with the most recent, the UK National Joint Registry (UK NJR), beginning in 2003. We identify commonalities and differences in the structure, function and methods of reporting among these national registries.

Method: Data was collected from the annual reports of the various registries, published literature and personal contact with registry coordinators and directors.

Results: Commonalities include registry ownership, source of funding, procedure types collected, method of data collection and validation of data. Most registries are owned by the national Orthopaedic Association or a government agency. The most common source of funding is government; membership fees and a mandated implant levy are also used. Most national registries collect total hip and knee replacements, primaries and revisions. Hemiarthroplasties are not commonly collected, though some registries collect additional joints (including shoulder, elbow, wrist, finger, ankle and toe). The most common method of data collection is paper-based, usually from theatre, with subsequent data entry at the registry. Electronic data collection is used to supplement the paper-based system in some countries, while the Swedish Hip Registry and the UK NJR utilise a web application for the submission of data. Most registries attempt to validate their data against hospital inpatient data held by government. Differences include reporting of rates, cost per registration and definitions. Failures of primary implants may be reported as cumulative proportions, true incidence rates or survival probabilities. This leads to difficulties in comparison of data among the national registries. The cost of registering a procedure varies up to five-fold across countries.

Conclusion: There are obvious opportunities for collaboration between national joint replacement registries, however some issues need to be addressed. These include definitions of what is collected, for example hemiarthroplasties, and methods of analysis and reporting, especially revision rates.

Introduction

The American Joint Replacement Registry (AJRR) was created to capture total hip (THA) and total knee arthroplasty (TKA) procedural data in order to conduct implant-specific survivorship analyses, produce risk-adjusted patient outcome data, and provide hospitals and surgeons with quality benchmarks. The purpose of this study is to compare early reports from the AJRR to other national registries to identify similarities and differences in surgeon practice and potential topics for future analysis.

Implant registries are set up to register implants. They therefore collect information about both primary and revision joint replacements. If a revision is linked to a primary it is then possible to determine the revision rate of the primary. This information is, however, of limited value as detailed information that affects the revision rate such as indications for the primary and the revision, and surgical technique used are not recorded. As a result comparisons of different implant designs and implant types are not reliable. For example implants that are commonly used in young or active patients are likely to have higher revision rates than those used in elderly sedate patients even though they may be better. Similarly, implants that are easy to revise will have higher revision rates than those more difficult to revise even if they provide better functional results. Finally, implants that are commonly used by more experienced surgeons will tend to have lower revision rates than those used by less experienced surgeons. Data from registries are therefore useful for identifying hypotheses that can formally be tested in other ways.

Over the past 40 years information from large institutional total joint registries have aided in patient clinical care and follow-up efforts, have helped drive improvements in clinical practice, and have been a powerful tool for generating research studies on large well documented populations of patients. Still, these efforts are limited in that they are expensive, usually reflect a single institutional experience, and results can be biased by the larger volumes or experience at the typically large academic centers which have such registries in place.

National registry efforts in other countries including Scandinavia, Australia, and the UK have resulted in improved outcomes and a decreased number of revision procedures by a combination of early identification and withdrawal of poorly performing implants, altered surgical techniques, implant choices and behaviors by surgeons, changes in practices by hospitals, and modification in requirements and incentives by payors and regulatory agencies.

The American Joint Replacement Registry (AJRR) is a collaborative multi-stakeholder, independent, not-for-profit 501 c3 organisation established in 2009 for data collection and quality improvement initiatives relating to total hip and knee arthroplasty. AJRR is a national registry effort with the goal of enrolling more than 90% of the over 5,000 hospitals performing nearly 1 million hip and knee arthroplasties each year in the US. AJRR is supported by contributions from the American Academy of Orthopedic Surgeons (AAOS), the American Association of Hip and Knee Surgeons (AAHKS), the Hip Society, the Knee Society, Health Insurers, Medical Device Manufacturers, and individual orthopaedic surgeons via designated contributions through the Orthopedic Research and Education Foundation (OREF).

The overarching goal of AJRR is to improve arthroplasty care for patients through the collection and sharing of data on all primary and revision total joint replacement procedures in the U.S. The mission of the registry is to enhance patient safety, and improve the value of arthroplasty care. This will be accomplished by providing national benchmarks for implant, surgeon and hospital performance which serves to modify behaviors thereby decreasing the revision burden, improving outcomes and reducing costs.

From the time of incorporation in 2009 up to October 2013 the AJRR has secured the participation of 218 hospitals in 47 different states in the formal enrollment process, and have level one data submission from more than 100 institutions on over 63,000 hip and knee procedures.

In addition to publicly available annual reports, confidential specific individual reports for hospitals, surgeons and manufacturers will be available by subscription with an option for future confidential online direct data queries by an individual or entity regarding their own individual performance compared to national benchmark values.

In summary, registry studies have provided a rich source of information for improving arthroplasty care over the past four decades, with the emergence and increasing interaction of national registries a major factor in current efforts to increase both the quality and value of the health care of entire populations. The development, support and continued expansion of a national registry in the US must remain a central focus if we wish to improve as much as possible the arthroplasty care provided to all patients in our country.

There is an ongoing revolution in the use of data within orthopaedics and medicine in general, with an imperative for surgeons to be involved from the bottom up and better define the data collection culture.

The use of registries plays a major role in the development of “big data” in orthopaedics. There are multiple examples that are already set up and running, both those inspired and set up by clinicians or those where the main stakeholders may lay people, with some input from clinicians. The British Limb Reconstruction society is no exception, with registries for lengthening nails and pilon fractures due to roll out imminently.

The BLRS has tasked this years BOA clinical leadership fellow to investigate the current state of registries among the specialist orthopaedic societies. In particular, comparison of the already well established registries and national audits with the development of registry projects in the smaller societies.

The issues of funding, consent, infrastructure and governance each infer particular challenges when translating the methods of the larger registries to the needs and resources of a smaller group. We have aimed to consider these challenges in relation to the set-up of the BLRS registries in order to better understand the potential future pitfalls and opportunities.

Background

Prosthetic implants used in primary total hip replacements have a range of bearing surface combinations (metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, metal-on-metal); head sizes (small <36mm, large 36mm+); and fixation techniques (cemented, uncemented, hybrid, reverse hybrid), which influence prosthesis survival, patient quality of life, and healthcare costs. This study compared the lifetime cost-effectiveness of implants to determine the optimal choice for patients of different age and gender profiles.

Background:

The use of registry data to detect and eliminate inferior devices is based on the assumption that the results of the first cases performed with a new device are indicative of how the same implant would perform with widespread usage. However, existing registry data clearly proves that the performance of individual implants is very surgeon dependent. In this study we utilized a computer simulation of a large implant registry to address the question: How does the pairing of different surgeons with different implants affect the ability of registries to correctly identify inferior devices?

BACKGROUND

The use of registry data to detect and eliminate inferior devices is based on the assumption that the results of the first cases performed with a new device are indicative of how the same implant would perform with widespread usage. However, existing registry data clearly proves that the performance of individual implants is very surgeon dependent. In this study we utilized a computer simulation of a large implant registry to address the question: How does the pairing of different surgeons with different implants affect the ability of registries to correctly identify inferior devices?

Aims. Loosening of components after total knee arthroplasty (TKA) can be associated with the development of radiolucent lines (RLLs). The aim of this study was to assess the rate of formation of RLLs in the cemented original design of the ATTUNE TKA and their relationship to loosening. Methods. A systematic search was undertaken using the Cochrane methodology in three online databases: MEDLINE, Embase, and CINAHL. Studies were screened against predetermined criteria, and data were extracted. Available National Joint Registries in the Network of Orthopaedic Registries of Europe were also screened. A random effects model meta-analysis was undertaken. Results. Of 263 studies, 12 were included with a total of 3,861 TKAs. Meta-analysis of ten studies showed high rates of overall tibial or femoral RLLs for the cemented original design of the ATTUNE TKA. The overall rate was 21.4% (95% confidence interval (CI) 12.7% to 33.7%) for all types of design but was higher for certain subgroups: 27.4% (95% CI 13.4% to 47.9%) for the cruciate-retaining type, and 29.9% (95% CI 15.6% to 49.6%) for the fixed-bearing type. Meta-analysis of five studies comparing the ATTUNE TKA with other implants showed a significantly higher risk of overall tibial or femoral RLLs (odds ratio (OR) 2.841 (95% CI 1.219 to 6.623); p = 0.016) for the ATTUNE. The rates of loosening or revision for loosening were lower, at 1.2% and 0.9% respectively, but the rates varied from 0% to 16.3%. The registry data did not report specifically on the original ATTUNE TKA or on revision due to loosening, but ‘all-cause’ five-year revision rates for the cemented ATTUNE varied from 2.6% to 5.9%. Conclusion. The original cemented ATTUNE TKA has high rates of RLLs, but their clinical significance is uncertain given the overall low associated rates of loosening and revision. However, in view of the high rates of RLLs and the variation in the rates of loosening and revision between studies and registries, close surveillance of patients who have undergone TKA with the original ATTUNE system is recommended. Cite this article: Bone Joint J 2023;105-B(6):610–621

Increased collection of patient-reported outcome measures (PROM) in registries enables international comparison of patient-centered outcomes after knee and hip replacement. We aimed to investigate 1) variations in PROM improvement, 2) the possible confounding factor of BMI, and 3) differences in comorbidity distributions between registries. Registries affiliated with the International Society of Arthroplasty Registries (ISAR) or OECD membership countries were invited to report aggregate EQ-5D, OKS, OHS, HOOS-PS and KOOS-PS values. Eligible patients underwent primary total, unilateral knee or hip replacement for osteoarthritis within three years and had completed PROMs preoperatively and either 6 or 12 months postoperatively, excluding patients with subsequent revisions. For each PROM cohort, Chi-square tests were performed for BMI distributions across registries and 12 predefined PROM strata (male/female, age 20-64/65-74/>75, high or low preoperative PROM scores). Comorbidity distributions were reported for available comorbidity indexes. Thirteen registries from 9 countries contributed data, n~130000 knee (range 140 to 79848) and n~113000 hip (range 137 to 85281). Mean EQ-5D index values (10 registries) ranged from 0.53 to 0.71 (knee) and 0.50 to 0.70 (hips) preoperatively and 0.78 to 0.85 (knee) and 0.83 to 0.87 (hip) postoperatively. Mean OKS (6 registries) ranged from 19.3 to 23.6 preoperatively and 36.2 to 41.2 postoperatively. Mean OHS (7 registries) ranged from 18.0 to 23.2 preoperatively and 39.8 to 44.2 postoperatively. Four registries reported KOOS-PS and three reported HOOS-PS. Proportions of patients with BMI >30 ranged from 35 to 62% (10 knee registries) and 16 to 43% (11 hip registries). For both knee and hip registries, distributions of patients across six BMI categories differed significantly among registries (p30 were for patients in the youngest age groups (20 to 64 and 65 to 74 years) with the lowest baseline scores. Additionally, females with lowest preoperative PROM scores had highest BMI. These findings were echoed for the OHS and OKS cohorts. Proportions of patients with ASA scores ≥3 ranged from 7 to 42% (9 knee registries) and 6 to 35% (8 hip registries). PROM-score improvement varies between international registries, which may be partially explained by differences in age, sex and preoperative scores. BMI and comorbidity may be relevant to adjust for

Aims. This study aimed to investigate the estimated change in primary and revision arthroplasty rate in the Netherlands and Denmark for hips, knees, and shoulders during the COVID-19 pandemic in 2020 (COVID-period). Additional points of focus included the comparison of patient characteristics and hospital type (2019 vs COVID-period), and the estimated loss of quality-adjusted life years (QALYs) and impact on waiting lists. Methods. All hip, knee, and shoulder arthroplasties (2014 to 2020) from the Dutch Arthroplasty Register, and hip and knee arthroplasties from the Danish Hip and Knee Arthroplasty Registries, were included. The expected number of arthroplasties per month in 2020 was estimated using Poisson regression, taking into account changes in age and sex distribution of the general Dutch/Danish population over time, calculating observed/expected (O/E) ratios. Country-specific proportions of patient characteristics and hospital type were calculated per indication category (osteoarthritis/other elective/acute). Waiting list outcomes including QALYs were estimated by modelling virtual waiting lists including 0%, 5% and 10% extra capacity. Results. During COVID-period, fewer arthroplasties were performed than expected (Netherlands: 20%; Denmark: 5%), with the lowest O/E in April. In the Netherlands, more acute indications were prioritized, resulting in more American Society of Anesthesiologists grade III to IV patients receiving surgery. In both countries, no other patient prioritization was present. Relatively more arthroplasties were performed in private hospitals. There were no clinically relevant differences in revision arthroplasties between pre-COVID and COVID-period. Estimated total health loss depending on extra capacity ranged from: 19,800 to 29,400 QALYs (Netherlands): 1,700 to 2,400 QALYs (Denmark). With no extra capacity it will take > 30 years to deplete the waiting lists. Conclusion. The COVID-19 pandemic had an enormous negative effect on arthroplasty rates, but more in the Netherlands than Denmark. In the Netherlands, hip and shoulder patients with acute indications were prioritized. Private hospitals filled in part of the capacity gap. QALY loss due to postponed arthroplasty surgeries is considerable. Cite this article: Bone Jt Open 2022;3(12):977–990