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.