The outcome of the cementless tapered SL-Plus stem: an analysis of arthroplasty register data

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

Implant Survival of 680 Consecutive EcoFit® Flat Single-Wedge Cementless Femoral Stems is Equivalent to the Taperloc® Total Hip Arthroplasty Series

Introduction

The EcoFit® total hip endoprosthesis has recently been approved for clinical use in the USA as a substantially equivalent implant to the Taperloc® Hip System, but no report has directly compared their long-term results so far. The primary aim of the presented single-hospital EcoFit® cohort analysis was to determine femoral stem survival rates at 5/10 years of follow-up in comparison to eight Taperloc® studies published within the last decade (2011-2021). The secondary aim was to find out whether femoral stem survival depended on the patients' age, gender and the operating surgeon.

Materials and Methods

The retrospective surgeon-stratified observational cohort study included 680 consecutive patients with primary EcoFit® femoral stem implanted at the same operating theatre block of a single tertiary hospital between April 2009 and December 2015. Survival analyses after 6-12 years of follow-up were performed with the Kaplan-Meier method and the Cox regression.

Results

The cumulative proportion of revision-free surviving EcoFit® femoral stems 5/10 years after the primary implantation was 96/94%, respectively, and the cumulative proportion of unremoved stems was 99/98%, respectively. The EcoFit® stem revision rate of 0.46 per 100 components-years was not significantly different from most Taperloc® cohorts. Higher age increased the risk of subsequent EcoFit® femoral stem revision (hazard ratio 1.039, p = 0.048) while the impact of gender and the operating surgeon was not statistically significant.

Conclusions

The study presents the first surgeon-stratified cohort analysis of the EcoFit®-Implantcast femoral stem from a single hospital with 5851 component years of observation. Long-term EcoFit® survival rates are comparable to the Taperloc® hip system. Caution is warranted when using such flat cementless single-wedge stems in the elderly population.

Surgeon-stratified cohort analysis of 1976 cementless Zweymüller total hip arthroplasties from a single hospital with 23,255 component years of follow-up

INTRODUCTION

The third-generation Zweymüller hip endoprosthesis has been used for decades with excellent results in arthroplasty registries, but surgeon-stratified reports on this implant are still scarce. The aim of the presented single-hospital cohort analysis of the third-generation Endoplus-Zweymüller primary total hip arthroplasty was to determine implant survival rates until the first revision/removal at 10/15/20/25 years after implantation and to find out whether implant survival depended on the operating surgeon, patient's age and gender, operated side (right/left), season of the year and the set of implanted components (SL-PLUS femur, BICON-PLUS acetabulum or both components).

MATERIALS AND METHODS

The retrospective observational cohort study included 1976 consecutive patients with primary BICON/SL-PLUS Zweymüller hip endoprosthesis implanted at the same operating theater block of the University Medical Centre Ljubljana, Department of Orthopaedic Surgery (Ljubljana, Slovenia) between January 1, 1993 and May 1, 2014. Survival analyses were performed with the Kaplan-Meier method and the Cox regression analysis after minimum 5 and maximum 26 years of follow-up.

RESULTS

At 10/15/20/25 years after implantation, the cumulative proportion of revision-free surviving Zweymüller total hip endoprostheses was 92/90/85/81% and the cumulative proportion with unremoved immobile components was 93/91/87/84%, respectively. After adjustment for age, gender and operated side, less experienced surgeons (odds ratios 2.34-5.00), season of the year at primary implantation (spring vs. winter odds ratio 1.74) and the use of BICON-PLUS acetabulum with femoral stem from another manufacturer (odds ratio 2.23) were significant risk factors of worse implant survival.

CONCLUSIONS

The study presents the largest published third-generation Zweymüller BICON/SL-PLUS total hip arthroplasty cohort from a single non-developmental hospital with 23,255 component years of observation. Study findings indicate the impact of environmental factors at primary implantation and variability between different surgeons on the long-term implant survival.

Survival Rate and Application Number of Total Hip Arthroplasty in Patients With Femoral Neck Fracture: An Analysis of Clinical Studies and National Arthroplasty Registers

BACKGROUND

Total hip arthroplasty (THA) is an increasingly popular treatment option for fractured neck of femur (NOF). The primary aim of this study is to systematically review all literature on primary THA and hemiarthroplasty (HA) after fractured NOF to calculate an overall revision rate. Furthermore, we wanted to compare primary THA implantations after fractured NOF between different countries in terms of THA number per inhabitant.

METHODS

All clinical studies on THA and HA for femoral neck fractures between 1999 and 2019 were reviewed and evaluated with a special interest on revision rate. Revision rate was calculated as "revision per 100 component years." THA registers were compared between different countries with respect to the number of primary implantations per inhabitant.

RESULTS

THA studies showed a mean revision rate of 11.8% after 10 years, which was lower than a 24.6% 10-year revision rate for HA. We identified 8 arthroplasty registers that revealed an annual average incidence of THA for fractured NOF of 9.7 per 100,000 inhabitants.

CONCLUSION

This study showed that patients with THA were less likely to be revised at 10 years compared to HA. We found similar annual numbers of THAs for fractured NOF per inhabitant across countries. The results of this analysis can be used to rank present and future national THA numbers within an international context.

Fretting and Corrosion Between a Metal Shell and Metal Liner May Explain the High Rate of Failure of R3 Modular Metal-on-Metal Hips

BACKGROUND

The R3 acetabular system used with its metal liner has higher revision rates when compared to its ceramic and polyethylene liner. In June 2012, the medical and healthcare products regulatory agency issued an alert regarding the metal liner of the R3 acetabular system.

METHODS

Six retrieved R3 acetabular systems with metal liners underwent detailed visual analysis using macroscopic and microscopic techniques.

RESULTS

Visual analysis discovered corrosion on the backside of the metal liners. There was a distinct border to the areas of corrosion that conformed to antirotation tab insertions on the inner surface of the acetabular shell, which are for the polyethylene liner. Scanning electron microscopy indicated evidence of crevice corrosion, and energy-dispersive X-ray analysis confirmed corrosion debris rich in titanium.

CONCLUSION

The high failure rate of the metal liner option of the R3 acetabular system may be attributed to corrosion on the backside of the liner which appear to result from geometry and design characteristics of the acetabular shell.

Good mid- to long-term THA outcomes with a modified cementless rectangular biconical stem design

PURPOSE

Second- and third-generation cementless Zweymüller stems have achieved good long-term outcomes in total hip arthroplasty (THA). The PPF cementless proximal press-fit femoral stem (Biomet Inc.) is based on the Zweymüller stem, with some prominent design differences. This study was designed to assess its performance in terms of survivorship, clinical function, and radiographic outcomes.

METHODS

We retrospectively analysed 250 patients (303 hips) who underwent THA between 1998 and 2011. Patients attended a follow-up visit a mean 10.9 ± 2.6 years after the procedure. All patients underwent radiographic examination and were clinically assessed for Forgotten Joint Score (FJS) and pain visual analogue scale (VAS). Survivorship was calculated using Kaplan-Meier analysis.

RESULTS

Clinical data were available for 142 patients (192 hips) and radiographic data for 79 patients (109 hips). Stem survival was 99.1% (95% confidence interval [CI] 96.6%-99.8%) at 10 years and 95.6% (95% CI 96.6%-99.8%) at 15 years. The median postoperative FJS was 91 (interquartile range [IQR], 75-100). The median VAS score was 0 (IQR, 0-2). Radiolucent lines were observed in 47 hips (43.1%). 25 hips (22.9%) had Grade I ossification, 17 (15.6%) Grade II, and 2 (1.8%) Grade III. 12 hips (11.0%) had osteolysis in at least 1 femoral zone.

CONCLUSIONS

The cementless proximal press-fit femoral stem was associated with good mid- to long-term survival and functional outcomes. The current design can be considered equivalent to the second- and third-generation Zweymüller stems.

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.

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.

Quality and reproducibility of French publications on total hip arthroplasty

INTRODUCTION

The goal of the Quality of Literature in Arthroplasty (QoLA) project launched in 2009 was to compare the implant results from clinical studies published in indexed scientific journals with those found in reference national registers. The potential biases in the chosen articles (country of origin, inventor involved in study, methodological quality) were systematically analyzed and the revisions per 100 observed component years (Revp100OCY) index was calculated. For a given implant, a differential factor greater than 3 between the Revp100OCY index for published series and the one from registers was considered as indicative of a potential selection (inventor) or publication (conflict of interest) bias. Although initially performed on English publications, this methodology was subsequently applied to French publications in the field of total hip arthroplasty (THA).

MATERIAL AND METHODS

French publications indexed in Medline (Rev Chir Orthop and Orthop Trauma Surg Res since 2009) were analyzed. These studies involved implants designed in France (ABG, Corail stem, Cerafit/Osteal, Bousquet) or that were used worldwide (Omnifit stem, Alloclassic and Charnley-type or Müller-type implants). The articles or abstracts selected had to contain sufficient information (number of revisions, number of cases and/or revisions, average follow-up) to allow the Revp100OCY index to be calculated.

RESULTS

Overall, the average Revp100OCY index for THA series published in French was 0.76, which is consistent with the worldwide average of 1.29. For the ABG System, the Revp100OCY index was 1.5, which was higher than register data (0.77). Cemented Charnley-type stems had a Revp100OCY index of 1.68 (register 0.64) and low friction arthroplasty type THA had a Revp100OCY index of 0.59 (register 0.33). The Revp100OCY index was slightly lower relative to register data for the Müller THA (0.22 versus 0.33), Corail stem (0.1 versus 0.24), Omnifit (0.26 versus 0.37) and Alloclassic (0.21 versus 0.49). Other implants without comparable register data had a relatively high Revp100OCY index: 1.2 for the Bousquet dual mobility cup and 1.35 for the Osteal/Cerafit hybrid system.

CONCLUSIONS

The few studies published in French include only a limited number of cases, but their follow-up is long and the revision rate consistent with register data. There is no indication of any type of bias in French scientific publications relative to the reproducibility of THA results.

Application and survival curve of total hip arthroplasties: a systematic comparative analysis using worldwide hip arthroplasty registers

PURPOSE

The aim of the study was to compare primary total hip arthroplasty (THA) implantations between different countries in terms of THA number per inhabitant, age, and procedure type and to compare the survival curve including all THAs using hip arthroplasty registers.

METHODS

THA registers were compared between different countries with respect to the number of primary implantations per inhabitant and age, procedure type and survival curve. We performed a literature search for all national hip arthroplasty registers providing annual reports for 2009 or, if not available, a more recent period. The data from these reports were analysed in terms of number, age distribution and procedure type of primary THAs and survival curves.

RESULTS

We identified nine hip arthroplasty registers, which comprised sufficient data to be included. A large variation was found in the annual number of primary THA implantations per inhabitant. The procedure type varied greatly as well, e.g. in Sweden 67 % are cemented THAs whereas in Emilia-Romagna (Italy) 89 % are cementless THAs.

CONCLUSIONS

This study revealed large differences in terms of the annual number of primary THAs per inhabitant and primary THA procedure type across countries. These data can be used to rank local primary THA implantations within an international context.