Joint-preserving effect and patient-reported outcomes of transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head

Background This study assessed the hip survival rate and patient-reported outcome measures (PROMs) of transtrochanteric curved varus osteotomy (CVO) for osteonecrosis of the femoral head (ONFH) compared with those of conservative management. Methods The CVO group comprised 32 consecutive patients (39 hips) who underwent CVO for ONFH between 2000 and 2011. The conservative group consisted of 36 consecutive patients (37 hips) who were managed conservatively for at least 1 year after collapse and who had ONFH classified by the Japanese Investigation Committee of Health and Welfare as type B or C1, for which CVO is indicated. Kaplan–Meier analysis of hip survival used any ONFH-related therapeutic surgery as the endpoint. PROMs were evaluated for all patients with surviving hips and radiographs available at the latest follow-up. Result The 10-year hip survival rate in the CVO group was 86.7%, which was significantly higher than the 51.0% 5-year survival rate in the conservative group (p < 0.0001). The Oxford Hip Score and UCLA Activity Score were significantly better in the CVO group without joint space narrowing than in the conservative group, with no significant differences between the CVO group with joint space narrowing and the conservative group. Conclusion CVO could preserve hip joints more effectively than conservative follow-up after collapse, although the presence of joint space narrowing could reduce satisfaction levels even in patients with long-term hip survival.