Proximal placement of the acetabular component in total hip arthroplasty. A long-term follow-up study. A retrospective review was undertaken of thirty-seven hips (thirty-four patients) that had had a complex cemented total hip arthroplasty. In these hips, circumstances had necessitated that the center of the hip be placed farther proximally, as measured from the interteardrop line, than the anatomical position that is normally used. The mean duration of clinical and roentgenographic follow-up was eleven years (range, seven to seventeen years), and the mean age of the patients was fifty-one years (range, sixteen to seventy-three years). Most of these hips had a major deficiency or defect of the acetabular bone stock, or both. Of the six acetabular components (16 per cent) that became loose and were followed for ten years, only one needed revision. Because this study was aimed specifically at assessment of the acetabular component, if the femoral component alone needed revision, the final clinical rating that was used was the one obtained after the femoral revision. Thirty-one hips (84 per cent) were rated as having a good or excellent result; they had an average Harris hip-rating score of 43 points preoperatively and 93 points postoperatively. Thirty-three of the thirty-seven acetabular components were not substantially displaced laterally as compared with the anatomical location that is normally used. Our findings suggest that, when circumstances dictate, proximal positioning of the acetabular component without lateral displacement can give an acceptable result in cemented total hip-replacement procedures. 