Hemi-resurfacing versus total resurfacing for osteonecrosis of the femoral head.

PURPOSE To compare mid-term outcomes of hemi-resurfacing arthroplasty (HRA) and total resurfacing arthroplasty (TRA). METHODS Seven men and 5 women (16 hips) aged 33 to 72 (mean, 50) years underwent HRA, whereas 7 men and 3 women (16 hips) aged 23 to 52 (mean, 40) years underwent metal-on-metal TRA; all were for osteonecrosis of the femoral head. In the HRA and TRA groups respectively, 10 and 8 hips were steroid-induced, whereas 6 and 8 hips were related to alcohol abuse. Surgery for 12 and 4 hips entailed the posterolateral approach, whereas 4 and 12 hips entailed the Hardinge approach. Usually, HRA was performed for early stages of the disease, and TRA for more advanced stages. 12 and 6 hips were classified as JOA stages 1 to 3A, whereas 4 and 10 hips as stages 3B to 4. All the hips were JOA types C1 or C2. RESULTS In the HRA and TRA groups respectively, the mean follow-up period were 6.5 and 5.5 years. The mean total JOA hip scores were 57 and 54 preoperatively, 93 and 97 at one year, and 84 and 96 at the final follow-up (p<0.01). The higher score in the TRA patients was mainly attributed to improvement in the pain score. In the HRA group, 12 hips developed groin pain or groin discomfort while walking, though only 4 of them showed apparent joint-space narrowing. Five patients underwent revision surgeries (conversion to total hip arthroplasty) owing to a femoral neck fracture, acetabular protrusio, osteoarthritic change, and severe groin pain. Patients having TRA had no revision surgery and did not complain of groin pain. Implants in both groups were radiographically stable. CONCLUSION TRA were superior to HRA in terms of pain relief and implant survival, even though the former procedure was used for more advanced cases.