Twenty-one hips in thirteen patients with avascular necrosis of the femoral head (AVN) were treated with surgical implantation of cementless bioplar arthroplasty (BHA) or cementless total hip arthroplasty (THA). In all cases, the same femoral compnent (Harris-Galante type) was used. The average age of the patients at the time of surgery was 41 years. The minimum follow-up period was 72 months while the average follow-up period took 112 months. Patients were rated using the Merle d'Aubigne hip score, as well as serial radiographs. The average hip score at follow-up examination was 16.1 in the THA group and 15.6 in the BHA group. Radiolucent lines in the BHA group were more likely to extend distally than the THA group. Although the results of this study support the use of both BHA and THA at almost equally preferable levels, the extension of radiolucent lines in the BHA group remains a serious concern.