Spontaneous Osteonecrosis of the Knee Treated with Autologous Chondrocyte Implantation, Autologous Bone-Grafting, and Osteotomy

Abstract

Spontaneous osteonecrosis of the knee is a disease whose primary etiology remains unknown. First described by Ahlback et al.1 in 1968, it is now categorized as either primary (spontaneous) or secondary osteonecrosis2. Primary osteonecrosis usually presents in people over the age of fifty years, with sudden onset of pain, most frequently in the medial femoral condyle. Secondary osteonecrosis is associated with certain risk factors, such as corticosteroid therapy and alcohol use, and is usually encountered in younger people. In patients with advanced disease or for whom nonoperative treatment has failed, surgery is recommended, typically partial or total joint replacement3-5. Reports of non-arthroplasty procedures are limited. Debridement, curettage, microfracture surgery, osteochondral allograft, bone-grafting, and isolated high tibial osteotomy (HTO) have been proposed6-12, but none have demonstrated proven clinical outcomes in long-term follow-up studies. The recent widespread introduction of autologous chondrocyte implantation (ACI) into clinical practice has renewed interest in biologic treatment options for osteonecrosis of the knee. Recently, Adachi et al.13 showed excellent short-term results with the use of ACI in conjunction with interconnected porous hydroxyapatite (IP-CHA) bone substitute for the treatment of steroid-induced osteonecrosis. In our patients, the abnormal subchondral bone was addressed with an autologous bone graft because of its superior osteogenic, osteoconductive, and osteoinductive properties. We describe two cases of spontaneous osteonecrosis of the knee that were treated with ACI, autologous bone-grafting, and osteotomy and followed for seven and nine years. The patients were informed that data concerning their cases would be submitted for publication, and they provided consent. Case 1. A fifty-year-old man with a history of seizures treated with Keppra (levetiracetam), Depakote (valproic acid), and Lamictal (lamotrigine) experienced spontaneous onset of sharp pain in the medial aspect of the knee in June 2000. …