Charnley low-frictional torque arthroplasty for avascular necrosis of the femoral head.

Forty-nine patients (mean age, 37 years; 20-50 years) had had 69 Charnley low-frictional arthroplasties for avascular necrosis of the femoral head. Their mean follow-up was 13.4 years (2-25 years). Five patients (8 hips) had no continuing follow-up, 5 (8 hips) are known to have died, 6 (7 hips) had had a revision at a mean follow-up of 16.4 years (11-25 years): 6 for cup loosening and 1 for a fractured stem and a loose cup. The remaining 33 patients (46 hips) had an excellent clinical result with all stems remaining soundly fixed, but 6 cups were radiologically loose at a mean follow-up of 16 years and 4 months. Wear and cup loosening are the main problems limiting the survival of the arthroplasty.