Long-term results of total hip arthroplasty with the cementless spotorno (CLS) system

Background: This study presents the long-term results of the Cementless Spotorno (CLS) total hip arthroplasty system and an analysis of factors associated with clinical and radiographic outcome. Methods: We studied a series of 120 consecutive CLS arthroplasties in a young patient group (mean age at surgery: 55.9 ± 5.9 years). The Merle d’Aubigné-Postel score, polyethylene (PE) wear, and radiographic status were recorded during follow-up. Survival analyses, repeated-measures analysis of variance, and a nested case-control study were used for statistical evaluation. Results: After a mean follow-up of 14.6 years (range 0.1-24.2 years, including revisions and lost to follow-up), 24 revisions had been performed, 16 of which for aseptic cup loosening. Kaplan-Meier survival analysis showed a 24-year survival of 72.8% (95% CI, 63.0%-82.6%) with revision for any reason as endpoint, and 80.1% (95% CI, 70.9%-89.3%) for revision for aseptic cup loosening. Mean final Merle d’Aubigné-Postel score was 16.1 points (range 7-18). Mean PE wear at final follow-up was 2.3 mm (range 0.6-6.8 mm). A higher rate of PE wear was associated with better clinical scores but also with revision for cup loosening. Factors associated with more PE wear were: younger age at surgery; 32 - mm head; longer follow-up; and steeper inclination angle. Conclusions: Beyond 10 years, the CLS stem is reliable, but the high revision rate for aseptic cup loosening is concerning, specifically with better performing (cementless) alternatives available.