The purpose of this study was to evaluate the 10-15 year follow-up results of total hip arthroplasty using a CLS (Cementless Spotorno)stem for osteonecrosis of the femoral head.

Out of a series of 67 CLS stems implanted in patients with osteonecrosis of the femoral head from February 1988 to February 1993, 33 hips of 29 patients were studied for 10 to 15 years postoperatively. The average age at the operation was 46.8 years and the average duration of follow up was 12.3 (10-15 years) years.

The average Harris hip score improved from 54.6 preoperatively to 95.8 postoperatively. Although one case showed radiologic stem loosening, no revision was performed because symptoms were not severe. Endosteal bone formation was observed in 29 (87.8%) casesand heterotophic ossification in 5. Acetabular cup loosening occurred in 1 case, and the acetabular revision was performed. Acetabularcup migration was not noted, though loosening was observed in the single case.

Ten to fifteen year follow-up results of total hip arthroplasty using CLS stem for the osteonecrosis of the femoral head showedan excellent results with good osseointegration of the components. Therefore, we believe that CLS stem design and surface treatment is effective in terms of the longevity and produces good results.