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

Abstract

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. 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. 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, <i>p</i> = 0.048) while the impact of gender and the operating surgeon was not statistically significant. 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.