Long-term results of the cementless ALLOCLASSIC hip arthroplasty system using a 28-mm ceramic head: with a retrospective comparison to a 32-mm head.

One hundred twenty-four total hip arthroplasties in 119 patients, all performed with the cementless ALLOCLASSIC hip arthroplasty system (SL stem and CSF cup; Centerpulse, Winterthur, Switzerland), were analyzed retrospectively. In all hips, a 28-mm head and an ultrahigh-molecular-weight polyethylene inlay were used. Of the 124 hips, 81 could be investigated clinically and radiologically after an average of 150.6 months (range, 133-169 months). Twenty-six patients (26 hips) died in the interim. One of these patients had septic cup loosening. Seventeen hips (16 patients) were not available for follow-up because of health reasons (12 hips in 11 patients), lack of cooperation (3 hips in 3 patients), or loss to follow-up (2 hips in 2 patients). Of the 124 total hip arthroplasties, 4 cups were removed (2 aseptic and 2 septic loosening). No stem had to be removed. If aseptic loosening is defined as the end point, the survival rate is 98.4% (95% confidence interval, 93.8%-99.6%) for the cup and 100% for the stem after 157 months. If revision for any reason is defined as the end point, the survival rate is 95.6% (95% confidence interval, 90.1%-98.3%). Before operation, the average Harris Hip Score was 36.4 points (21-46). At time of follow-up, the average Harris Hip Score was 89.7 points (54-100). Radiolucent lines and osteolyses were found only seldom (mostly in the proximal stem zones).