Survival rates of anatomically shaped and tapered slip cemented femoral implants: an analysis of 76,281 femoral implants of the Dutch arthroplasty register (LROI).

INTRODUCTION: In cemented total hip arthroplasty (THA) various shapes and geometries of femoral implants are in use. Collarless, polished, and tapered (CPT) implants, and anatomically shaped (AS) implants are most commonly used. Due to their different design features, this might lead to different survival outcomes. In this register-based study, overall implant survival and short-term complications of CPT and AS cemented implants were evaluated. METHODS: Data of the Dutch Arthroplasty Register (LROI) were used. Cemented femoral implants, which could be classified as CPT or AS were included in this study. Implants were excluded when no classification could be made or if implanted <100 times. Survival analyses were performed using Kaplan-Meier survival analysis and multivariable Cox-proportional hazard analysis. RESULTS: 76,281 cemented THAs were included. At a mean of 5.1 years follow-up (SD 3.1, range 0-12 years), the overall survival of the AS implants was higher compared with the CPT implants, with a survival, of 99.2% and 99.0% respectively (log-rank; p < 0.001). Multivariable regression analysis revealed a higher rate for revision because of loosening of the AS implants (HR 2; CI, 1.4-3.1). AS implants had a lower rate for periprosthetic fractures compared with the CPT implants (HR 0.13; CI, 0.07-0.23). CONCLUSIONS: Both designs show excellent overall survival rates at short-term follow-up. There is a higher overall survival of AS implants when compared with CPT implants. Revision for implant loosening, however, was statistically significantly higher in AS implants when compared with the CPT implants.

Disappointing long-term outcome of THA with carbon-fiber-reinforced poly-ether-ether-ketone (CFR-PEEK) as acetabular insert liner: a prospective study with a mean follow-up of 14.3 years.

INTRODUCTION: Insert liner wear of the acetabular component is one of the predictive values for survival of total hip arthroplasties (THAs). This prospective single-centre study was designed to evaluate the follow-up of carbon-fiber-reinforced poly-ether-ether-ketone (CFR-PEEK) insert liner used as bearing in cementless THAs. METHODS: 29 healthy patients with an indication for cementless THA were selected for a CFR-PEEK insert liner and followed over time. All patients received a cementless THA with a CFR-PEEK insert liner used as bearing. At different follow-up moments patients were routinely examined and were analysed using the Oxford Hip Score (OHS), the modified Merle d'Aubigne-Postel (MAP) score, and radiologically. At the follow up moments the plain radiographics where assessed for loosening, cyst formations and wear of the CFR-PEEK liners. RESULTS: At a mean of 14.3 years follow-up 4 revisions of the acetabular component were performed, resulting in a survival rate of 86.5% (CI 95%, 72.4-96.6). A statistically significant difference in OHS and MAP scores between pre- and postoperative follow-up moments was observed. The acetabular components of the remaining patients showed no radiological abnormalities at 14.3 years follow-up. The overall CFR-PEEK wear was low, with a mean of 0.81 (0.2-1.4) mm wear at 14.3 years follow-up. CONCLUSIONS: In this series we found an aseptic loosening with unclear reasons in 4 well-positioned acetabular components, hence we do not recommend routine use of CFR-PEEK insert liners as bearing in cementless THAs. All the remaining THAs and acetabular components were in situ without abnormalities at 14.3 years follow-up.