Calcium phosphate cement to prevent collapse in avascular necrosis of the femoral head.

Subchondral and articular collapse following nontraumatic osteonecrosis of the femoral head is an important cause of osteoarthritis in patients between ages 20 and 40. Because hip arthroplasty in the younger population is prone to early wear and failure, it is paramount to prevent collapse once osteonecrosis is detected. Natural remodeling of the osteonecrotic areas by adjacent normal bone is predominated by osteoclastic resorption, which weakens the cancellous bone and allows microfractures to occur before full healing can take place. Current treatment modalities include core decompression and various adjuncts such as bone graft, mesenchymal stem cells and tantalum implants to provide structural integrity and to speed bony creeping substitution. Calcium phosphate cement has been reported in the treatment of fractures, especially depressed tibial plateau fractures. It is slow to resorb and is gradually replaced by bone, allowing prolonged support of periarticular fractures during healing. We hypothesize that calcium phosphate cement in conjunction with standard decompression of osteonecrotic femoral head lesions can prevent collapse.