Low aseptic loosening and revision rate in Zweymüller-Plus total hip arthroplasty with ceramic-on-ceramic bearings

Abstract

A recent comparative study reported lower revision rate and higher survival in ceramic-on-ceramic (CoC) than in metal-on-metal (MoM) coupling in Zweymüller-Plus THA. We retrospectively studied 87 consecutive patients (94 hips), who primarily received Zweymüller-Plus THA (SL-Plus stem, ceramic 28-mm ball head, Bicon cup) with third-generation CoC bearing surfaces for osteoarthritis. Survival, revision and osteolysis rate were studied and compared to those observed in historical series from this institution with the same THA and MoM articulation. The mean ± SD follow-up was 7.4 ± 1.7 years (range 6-10 years). Four hips (4%) in four patients were revised 1-6 years following primary implantation: one (1%) for aseptic loosening of SL-Plus stem and Bicon 5 years after index surgery; one (1%) for malpositioning of the Bicon and recurrent dislocations 1 year following implantation; and two (2%) for septic loosening 1 and 6 years postoperatively. Intraoperatively on inspection, there were neither findings for impingement in the revised hips, nor fracture of the Bicon ceramic inlay and ball head. Expansile osteolysis was shown around SL-Plus stem and Bicon in the revised for aseptic loosening hip. With revision of any component for aseptic loosening as the endpoint, the survival was 99% (95% CI 91-100%), while for revision for any reason, it was 95% (95% CI 87-98%) at 10 years. Zweymüller-Plus THA with CoC bearings showed, at mid-term follow-up, high survival and low revision rate for aseptic loosening. These rates were better than the historical series of the same THA with MoM articulation performed by the same surgeon. Level IV.