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.
