Long-term outcomes of Phemister bone grafting for patients with non-traumatic osteonecrosis of the femoral head.

BACKGROUND: Phemister procedure is an effective treatment for early stage osteonecrosis of femoral head (ONFH). Since the long-term results of the Phemister procedure are less reported in the literature, the purpose of this study was to investigate the long-term outcomes of this bone grafting technique in patients with earlier stages of ONFH.

METHODS: From 1994 to 2010, 29 hips with pre-collapsed or early collapsed (< 2 mm) ONFH treated by Phemister procedure were evaluated. Among them, nine hips were Association Research Circulation Osseous (ARCO) stage IIA, 13 stage IIB, 4 stage IIC, and 3 stage IIIA. The mean age was 38.9 years. The mean follow-up was 14 years (1-21 years). Survivorship was analyzed with conversion to total hip arthroplasty (THA) as the endpoint.

RESULTS: At the final follow-up, 10 hips underwent THA at a mean of ten years (1-18 years). The overall clinical success rate for hip preserving was 65.5%, and radiological success rate was 31%. The mean Harris Hip Score improved from 50.3 to 76.1. The survival of hips was significantly inferior in female patients (P < 0.01), ARCO stage III disease (P = 0.03), lateral type lesion (P < 0.01), and necrotic index ≥ 0.67 (P < 0.01). The Cox proportional hazards model showed that gender, ARCO stage, and necrotic index were independent risk factors for conversion to THA.

CONCLUSION: The study showed acceptable results without complication in patients receiving Phemister procedure for early stage ONFH at a mean follow-up of 14 years. As a head-preserving procedure, Phemister technique is worthwhile for young patients to postpone the need for THA.