Superelastic cage implantation: a new technique for treating osteonecrosis of the femoral head with mid-term follow-ups.

We developed a device for the treatment of Ficat and Arlet stage II and III osteonecrosis of the femoral head. This device, which we named the "super-elastic cage," was designed to provide mechanical support for the necrotic weight-bearing area of the femoral head to prevent its collapse. The cage was used in combination with surgical removal of necrotic bone, insertion of vascularized pedical bone graft, or impacted autologous cancellous bone graft. A total of 93 hips in 62 patients at Ficat stage II to III were included in a 8-year study. Implantations were performed by 2 different approaches: Smith-Peterson approach and minimal invasive approach by the lateral side of great trochanter. The follow-up period was between 72 and 107 months. Of the femoral heads in this study, 82.7% survived. The superelastic cage implantation technique may offer an alternative treatment to the early and middle stages of osteonecrosis of the femoral head.