Even in extensive osteonecrosis of the femoral head in younger patients, a femoral head-preserving method is preferable. We developed a new technique using the lateral approach as used in traditional core biopsy; the osteonecrotic lesion was removed and impacted bone grafts were used to regain sphericity and prevent collapse. In this prospective one surgeon study, we included 28 consecutive hips in 27 patients with extensive osteonecrotic lesions (ARCO classification Stage 2 [11 hips], Stage 3 [14 hips]; and Stage 4 [three hips]); 14 hips had preoperative collapse. The mean age of the patients was 33 years (range, 15-55 years). At a mean followup of 42 months (range, 24-119 months), eight hips (29%) were converted to a total hip arthroplasty (THA). Of the 20 reconstructions that were in situ, 18 were clinically successful (90%) and 70% were radiologically successful. Patients who were younger than 30 years at surgery had a radiologically significant better outcome, even patients with higher stages of osteonecrosis. Patients with preoperative collapse and use of corticosteroids had disappointing results. This method is attractive as a salvage procedure, is relatively simple and quick, and it does not interfere with an eventual future hip arthroplasty.