Introduction. A transtrochanteric curved varus osteotomy (TCVO) is an excellent joint preserving surgical modality if the necrotic lesion can be moved to the non-weight bearing area as assessed by maximum abduction antero-posterior radiographs. The purpose of this article was to elucidate whether TCVO can reduce the volume of osteonecrosis after an index osteotomy as assessed by magnetic resonance imaging (MRI). Methods. Twenty patients (twenty hips) with non-traumatic osteonecrosis of the femoral head were followed for more than three years after an index operation and MRI examinations both before and at two years after surgery were retrospectively investigated. The average age at the time of operation was 40 years (range, 18 to 60 years), consisting of 13 men (13 hips) and 7 women (7 hips). The etiology and/or associated risk factors was steroid-associated osteonecrosis in 11 hips, alcohol associated in 7 hips, and idiopathic in 2. According to the classification of the Japanese Investigation Committee there was Type B in one hip, Type C-1 in 17 hips, and Type C-2 in 2 hips. Eight hips were in Stage 2, 10 in Stage 3A, and 2 in Stage 3B. Average follow-up was 4 years (range, 3 to 5 years). Results. The average varus angle was 26.5 degrees (range, 15 to 35 degrees), and the average leg length shortening was 11.8 millimeters (range, 2.5 to19 millimeters). The pre-operative average Harris hip score improved from 68 points to 97 points three years after TCVO. The bone union of the osteotomy was obtained at an average of 4 months (range, 3 to 8 months). A progression to collapse of the femoral head was observed in three hips. The pre-operative average necrotic volume by MRI was 12.8 cm. 3. (range, 6.4 to 20.9 cm. 3. ) and at two years after surgery the average necrotic volume significantly decreased to 9.2 cm. 3. (range, 1.7 to 16.3 cm. 3. ). Conclusion. The volume of osteonecrosis of the femoral head significantly decreased at two years after TCVO. The early clinical and radiographic results of TCVO were satisfactory

Introduction. The treatment of osteonecrosis of the femoral head (ONFH) in young and active patients remains a challenge. The purpose of this study was to determine and compare the clinical and radiographic results of the two different hip resurfacing systems; hemi-resurfacing and metal-on-metal total hip resurfacing in patients with ONFH. Methods. This study was a retrospective review of 20 patients with 30 hips who had ONFH and underwent hemi-resurfacing or total hip resurfacing between November 2002 and February 2006. We mainly performed hemi-resurfacing for early stage ONFH, and total hip resurfacing for advanced stages. Fifteen hips in 11 patients had a hemi-resurfacing component (Conserve, Wright Medical Co) with a mean age at operation of 50 years and an average follow-up of 5.5 years. Fifteen hips in 10 patients had a metal-on-metal total hip resurfacing component (Birmingham hip resurfacing, Smith & Nephew Co.) with a mean age at operation of 40 years and an average follow-up years. Results. The average postoperative Japanese Orthopaedic Association (JOA) hip scores were 86 points in hemi-resurfacing and 96 points in total hip resurfacing. The difference of pain score was a main factor to explain the difference of total JOA hip score in the two groups. Both implants were radiographically stable, but radiolucent lines around the metaphyseal stem were more frequent in total hip resurfacing. In hemi-resurfacing patients, ten of 15 hips had groin pain or groin discomfort and three hips were revised to total hip arthroplasties (THA) because of femoral neck fracture, acetabular protrusio, and osteoarthritic changes, respectively. In total hip resurfacing patients, there were no revisions and no groin pain observed. Conclusion. In the prosthetic treatment of young active patients with ONFH, it is theoretically desirable to choose an implant with a conservative design in anticipation of the future revision surgery. Hemi-resurfacing hip arthroplasty is the most conservative implant for the treatment of ONFH. However, the results of hemi-resurfacing in this study have been disappointing due to high revision rates and insufficient pain relief despite of the good implant stability. However, the pain relief and implant survivorship after total hip resurfacing were superior to the results of hemi-resurfacing, although the usages of the total hip resurfacing were for more advanced cases. These results suggest that total hip resurfacing was a more valuable treatment option for active patients with ONFH than hemi-resurfacing