No bias for developer publications and no difference between first-generation trochlear-resurfacing versus trochlear-cutting implants in 15,306 cases of patellofemoral joint arthroplasty.

PURPOSE AND HYPOTHESIS: The study aim was to assess the outcome of patellofemoral arthroplasty (PFA), paying particular interest to 'revisions for any reason'. The hypothesis was that there is a superior outcome of PFA reported in dependent clinical studies in contrast to independent clinical literature and that there is a superior outcome of 'trochlear-cutting' PFA in comparison with 'first-generation trochlear-resurfacing' implants. METHODS: Studies on PFA from its market introduction in 1955 onwards were systematically reviewed. The revision rate, which was calculated as 'revisions per 100 component years (CY)', was evaluated in 45 studies published in indexed, peer-reviewed international scientific journals. In addition, 'first-generation trochlear-resurfacing' and 'trochlear-cutting' implants as well as dependent and independent clinical literature were analysed. Furthermore, the data of three arthroplasty registers were analysed. RESULTS: A total of 15,306 PFA were included consisting of 2266 cases in worldwide literature data and of 13,040 cases in register data. 2.22 revisions per 100 CY were observed in worldwide literature data, which corresponds to a revision rate of 22.2% after 10 years. Revision rates between 18.9 and 27% after 10 years were shown by the included three national joint registers. In the group analyses no significant differences were detected. CONCLUSIONS: This meta-analysis did not reveal significant differences in the comparison between developer over independent publications and between 'first-generation-resurfacing' over 'trochlear-cutting' implants. In conclusion the data of developer publications do not seem to be biased. 'Trochlear-cutting' devices of PFA had slightly superior outcomes, but that benefit was not statistically significant. Nevertheless, we would recommend 'trochlear-cutting' devices for further use in PFA. LEVEL OF EVIDENCE: Meta-analysis of Level IV case series.

The incidence of implant fractures after knee arthroplasty.

PURPOSE: This study aimed to evaluate the incidence of "implant" fractures after knee arthroplasty using clinical literature and worldwide arthroplasty registers. The hypothesis was that register datasets report higher rates of these rare complications than clinical studies. METHODS: Calculations were based on the pooled incidence of revision operations after fractures of knee arthroplasties, comparing clinical studies published in MEDLINE-listed journals and annual reports from worldwide arthroplasty registers in a structured literature analysis based on a standardized methodology. RESULTS: Twelve clinical studies and datasets from six worldwide registers were included. Rates of fractures of knee arthroplasties were reported from 0.2 to 2.5 % in clinical studies versus 0.02-0.17 % in worldwide arthroplasty registers. CONCLUSIONS: Fractures of knee arthroplasty systems are rare complications, with clinical studies showing higher incidence rates than worldwide arthroplasty registries. Unicompartmental knee arthroplasty (UKA) implanted before 2000, constrained primary or revision constrained total knee arthroplasties, and patellar replacements showed the highest incidence of implant fracture. The results of this analysis can help clinicians to counsel patients on potential complications following knee arthroplasty. LEVEL OF EVIDENCE: III.

Quality of outcome data in knee arthroplasty.

BACKGROUND AND PURPOSE: Recent reports on developer bias in unicondylar knee arthroplasty led to concerns about quality of publications regarding knee implants. We therefore compared revision rates of registry and non-registry studies from the beginning of knee arthroplasty up to the present. We assessed the time interval between market introduction of an implant and emergence of reliable data in non-registry studies. MATERIAL AND METHODS: We systematically reviewed registry studies (n = 6) and non-registry studies (n = 241) on knee arthroplasty published in indexed, peer-reviewed international scientific journals. The main outcome measure was revision rate per 100 observed component years. RESULTS AND INTERPRETATION: For 82% of the 34 knee implants assessed, revision data from non-registry studies are either absent or poor. 91% of all studies were published in the second and third decade after market introduction. Only 5% of all studies and 1% of all revisions were published in the first decade. The first publications on revision rates of total knee arthroplasty (TKA) started 6 years after market introduction, and reliable data were found from year 12 onward in non-registry studies. However, in unicondylar knee arthroplasty (UKA) the first publications on revision rates could be found first 13 years after market introduction. Revision rates of TKA from non-registry studies were reliable after year 12 following market introduction. UKA revision rates remained below the threshold of registry indices, and failed to demonstrate adjustment towards registries. Thus, the superiority of registry data over non-registry data regarding outcome measurement was validated.

The incidence of implant fractures after total hip arthroplasty.

PURPOSE: Implant fractures after total hip arthroplasty (THA) are considered as rare in clinical practice. Nevertheless they are relevant complications for patients, physicians, and the public health system leading to high socioeconomic burdens. The aim of this study was to assess the incidence of fractures after THAs in a comparative analysis of clinical studies and worldwide arthroplasty register datasets. METHODS: We calculated the pooled incidence of revision operations after fractures of THAs in a comparison of clinical studies published in Medline-listed journals and annual reports of worldwide arthroplasty registers in a structured literature analysis based on a standardised methodology. RESULTS: Included clinical studies (sample-based datasets) were mono-centre trials comprising a cumulative number of approximately 70,000 primary implantations whereas worldwide national arthroplasty register datasets referred to 733,000 primary implantations, i.e. approximately ten times as many as sample-based datasets. In general, sample-based datasets presented higher revision rates than register datasets with a maximum deviation of a 14.5 ratio for ceramic heads, respectively. The incidence of implant fractures in total hip arthroplasty in pooled worldwide arthroplasty register datasets is 304 fractures per 100,000 implants. In other words, one out of 323 patients has to undergo revision surgery due to an implant fracture after THA in their lifetime. CONCLUSIONS: Implant fractures in total hip arthroplasty occur in a relevant number of patients. The authors believe that comprehensive arthroplasty register datasets allow more general evaluations and conclusions on that topic in contrast to clinical studies.

Overcoming boundaries of worldwide joint arthroplasty registers: the European Arthroplasty Register minimal dataset.

Worldwide joint arthroplasty registers are instrumental to screen for complications or implant failures. In order to achieve comparable results a similar classification dataset is essential. The authors therefore present the European Federation of National Associations of Orthopaedics and Traumatology (EFORT) European Arthroplasty Register (EAR) minimal dataset for primary and revision joint arthroplasty. Main parameters include the following: date of operation, country, hospital ID-code, patient's name and prename, birthday, identification code of the implant, gender, diagnosis, preoperations, type of prosthesis (partial, total), side, cementation technique, use of antibiotics in the cement, surgical approach, and others specifically related to the affected joint. The authors believe that using this minimal dataset will improve the chance for a worldwide comparison of arthroplasty registers and ask future countries for implementation.

Comparative pooled survival and revision rate of Austin-Moore hip arthroplasty in published literature and arthroplasty register data.

The aim was to evaluate the pooled survival and revision rate of Austin-Moore hip arthroplasty (AMHA) in published literature and arthroplasty register data. A comprehensive literature analysis of clinical publications and register reports was conducted with the main endpoints revision surgery and revision rate. Sixteen relevant clinical studies have been found to significantly underestimate revision rates by a ratio of 2.15 compared to register data sets. The medium-term outcome of AMHA showed significantly worse outcomes than the use of other bipolar implants, or modular cervicocephalic prostheses and data of journal publications on revision rates deviate significantly from data of arthroplasty registers.

Revision surgery after total joint arthroplasty: a complication-based analysis using worldwide arthroplasty registers.

The authors performed a complication-based analysis of total knee (TKA), total hip (THA), and total ankle arthroplasty (TAA) using worldwide arthroplasty registers. We extracted data with respect to reason for revision surgery and pooled causes. The most common causes for revisions in THA were aseptic loosening (55.2%), dislocation (11.8 %), septic loosening (7.5%), periprosthetic fractures (6%), and others. The most common causes in TKA were aseptic loosening (29.8%), septic loosening (14.8%), pain (9.5%), wear (8.2%), and others. The most common causes in TAA were aseptic loosening (38%), technical errors (15%), pain (12%), septic loosening (9.8%), and others. Revisions in TKA and THA differ with respect to type of complication. However, in case of TAA, higher rates of technically related complications are reported.

Pooled outcome of total hip arthroplasty with the CementLess Spotorno (CLS) system: a comparative analysis of clinical studies and worldwide arthroplasty register data.

PURPOSE: Our aim was to elucidate the pooled outcome of the CementLess Spotorno (CLS) system in total hip arthroplasty (THA). METHODS: We compared the outcome of clinical inventor studies, independent clinical studies, and worldwide register data. The main endpoints for analysis were revision rates. RESULTS: Twenty clinical studies were evaluated and, with one exception, overall found revision rates largely in line with register data. Revision rates (revisions per 100 observed component years) range from 0.15 (inventor study) to 0.28 (independent studies) and 0.43 (register datasets). CONCLUSION: Data of journal publications and register datasets using the CLS system do not differ significantly with respect to revision rates. Only the initial inventor study reports a revision rate three times lower than in pooled worldwide register datasets.

Outcome after total ankle arthroplasty-results and findings from worldwide arthroplasty registers.

PURPOSE: The data currently available concerning total ankle arthroplasty (TAA) does not allow valid conclusions in several clinically relevant areas. Total ankle arthroplasty imposes special requirements on the methodology of data collection, evaluation, publication and the assessment of register data. METHODS: We undertook a structured and descriptive analysis of all outcome data available from high-quality national arthroplasty registers worldwide. Register data from Sweden, Finland, Norway, New Zealand and Australia were included in the analysis. RESULTS: There are marked differences between Europe and Oceania with respect to indications. All data sets show revision rates of approximately 10 % at five years, of which about 40 % of cases are for aseptic loosening. Inlay fractures are relatively common, which indicates potential for the improvement of implants. The documentation of intraoperative surgical errors leading to revision surgery varies significantly among registers. A relevant number of complications are treated without an implant component being exchanged and therefore not covered by a register. CONCLUSIONS: The results of TAA are promising, but the revision rate is higher than for total hip or knee arthroplasty. TAA outcome measurement by means of registers has several specific requirements necessitating additional documentation beyond the basic data set. For methodological reasons the evaluation of results is more complex than for hip or knee arthroplasty. It will therefore be essential to standardise data collection and evaluation and develop a methodology addressing the specific needs of TAA.

Application and surgical technique of total knee arthroplasties: a systematic comparative analysis using worldwide registers.

PURPOSE: The aim of this study was to compare total knee arthroplasty (TKA) procedures between different countries with regard to epidemiological data and surgical technique by reference to the worldwide arthroplasty registers. METHODS: A systematic search was carried out using the EFORT website to identify the relevant arthroplasty registers. We extracted data with respect to the number of implanted TKAs, patients' age distribution, procedure types, and revision rates. After identification of 28 national arthroplasty registers, 11 offered sufficient data regarding the above mentioned parameters and were therefore included in the final analysis. RESULTS: A large variation was found in the annual number of primary TKA implantations per inhabitant with a reported range from 30 to 199 per 100,000 (mean 106). The fixation method varied strongly between the different registers as well, e.g. 90 % of totally cemented TKAs in Sweden, England and Wales, Slovakia, and New Zealand versus 54 % cemented fixation in Australia. Another significant difference between included countries was observed with respect to the use of patellar resurfacing in TKA. Whilst the Danish knee arthroplasty register reports a percentage of 72 % using a patellar button in TKA the register from Norway reports only a minority of 2 %. CONCLUSIONS: The comparison of arthroplasty registers revealed large differences regarding the annual number of primary TKAs per inhabitant and primary TKA procedure types. These variations may be explained by several factors such as patient demographics (prevalence of osteoarthritis) and national conditions such as healthcare systems (insurance status), number or availability of performing surgeons, medical facilities and surgeon-dependent factors such as definition of indications, education, tradition and experience.