Charnley-Kerboull total hip arthroplasty combining zirconia on polyethylene. A minimum eight-year follow-up prospective study

Zirconia was introduced in the 1980s for total hip arthroplasty (THA) with the expectation of lower polyethylene wear. The purpose of this prospective study was to evaluate the results of a continuous series of total hip arthroplasties combining a zirconia head with polyethylene socket at a minimum eight-year follow-up. We performed an open prospective clinical trial in 1997. Our study involved 51 consecutive patients (55 hips) with a mean age of 52.5 +/- 12 years (range, 25-76 years). All patients had a Charnley-Kerboull all-cemented hip replacement. A 22-mm stabilised yttrium tetragonal polycrystalline zirconia head (Y-TZP) was used in association with moderately cross-linked and annealed polyethylene. Clinical and radiological outcomes were assessed yearly. A survival analysis was performed using revision for any reason as the end-point. At a minimum eight-year follow-up, 12 patients (13 hips) were lost to follow-up (mean 26.8 months), two patients (two hips) had died, and six patients (six hips) were revised. The remaining 31 patients (34 hips) were alive and had not been revised on either the femoral or acetabular side at a mean follow-up of 117.1 months (range, 96-150 months). Mean functional score at last follow-up was 17.7. Mean linear head penetration was 0.23 mm/year. More than 90 % of the remaining hips had signs of periprosthetic osteolysis. Five stems were loosened. The survival at eight years was 87.3 % (95 % IC: 76.7-97.8). This study confirms earlier short-terms results, and demonstrates that zirconia should no longer be used in THA.