Outcomes of Curved Intertrochanteric Varus Osteotomy for Osteonecrosis of the Femoral Head with a Beak-Shaped Healthy Area.

Abstract

Indications for curved intertrochanteric varus osteotomy (CVO) for osteonecrosis of the femoral head (ONFH) with a beak-shaped healthy area (BHA) remain unclear. This study aimed to evaluate the clinical outcomes and radiographic findings of CVO for ONFH with BHA. This comparative study included 77 patients who were Japanese Investigation Committee type B and C1 ONFH. From January 2005 to December 2022, 21 patients (22 hips) who had a BHA underwent CVO (BHA group), whereas 56 patients (62 hips) who did not have a BHA underwent CVO (control group). The average follow-up period was 98.4 and 97.2 months in the BHA and control groups, respectively. Clinical and radiographic evaluations included the Harris Hip Score (HHS), complication rates, radiographic parameters, and survival rates. Endpoints were defined as conversion to total hip arthroplasty (THA) or radiographic failure. The pre- and postoperative HHS values were similar between the BHA and control groups. The complication rates were comparable between the groups. The postoperative intact ratio and varus angle showed no significant differences. In the BHA group, three cases of beak fractures occurred within the first year postoperatively. The 8-year survival rate based on conversion to THA and radiographic failure did not differ significantly between the groups. The clinical outcomes of CVO for ONFH with BHA were comparable to those of CVO for ONFH without BHA, indicating that CVO may be a viable joint-preserving option even in cases presenting with BHA.