Idiopathic Osteonecrosis of the Femoral Head

Idiopathic osteonecrosis of the femoral head (ONFH) is an ischemic disease characterized by a hip pain and limited range of motion, caused by a collapse of the femoral head. Preoperative planning should be made based on the width of the necrotic lesion as well as the patients’ age and social environment. When intact lesion remains in the femoral head, joint preserving procedures, including intertrochanteric curved varus osteotomy or transtrochanteric rotational osteotomy are considered. Bipolar head arthroplasty is indicated for patients with stage 3 who do not show joint space narrowing on radiographs. Total hip arthroplasty is indicated for stage 4 patients who show joint space narrowing on radiographs and CT images. To achieve favorable postoperative outcomes, it is essential carefully consider selection of the implant and approach, cup position, and whether previous femoral osteotomy has been performed.