Primary total hip arthroplasty without the use of bone cement: a 10-year follow-up of 157 hips.

BACKGROUND The cementless fixation technique in total hip arthroplasty (THA) was developed to solve clinical problems such as aseptic loosening and osteolysis which were thought to be associated with the use of bone cement. This retrospective study reports our mid-term results with cementless THA. METHODS A series of 173 consecutive, unselected cementless THA procedures using the Omnifit prosthesis was performed by a single surgeon. Sixteen hips were excluded from the study because of insufficient follow-up evaluation. One hundred and fifty-seven THAs with an average follow-up period of 10.2 (range, 5-12) years were retrospectively reviewed. RESULTS The overall revision rate was 7.0%. Ninety-five percent of unrevised hips achieved a Merle D'Aubigne hip score of 16 points or above. Radiographically, bone ingrowth occurred in all unrevised cups, and in 95% of unrevised stems. Osteolytic lesions, seen on 28.1% of femora and 8.9% of pelvises, appeared at an average of 3.8 years postoperatively. Femoral osteolytic lesions were confined to the proximal Gruen zones 1 and 7. The mean annual polyethylene wear rate was 0.15 mm. Approximately 1/3 of the hips were noted to have excessive wear. CONCLUSION These results suggest that cementless Omnifit THA provides stable fixation for as long as 12 years after implantation. Of significant concern is the high incidence of excessive polyethylene wear and associated osteolysis. Our experience also indicates that a femoral stem with a circumferential porous coating in the proximal region can protect the femur from distal osteolysis.