Osteoinductive agents in reconstructive hip surgery: A look forward

The use of autograft and allograft material to restore bone stock and promote healing and implant stabilization is a crucial part of total hip arthroplasty, especially in the revision situation. Recent research has centered on the use of osteoinductive materials such as osteogenic proteins or bone morphogenetic proteins to promote bone formation. These proteins are members of the transforming growth factor-beta superfamily of proteins that either alone or in combination with other regulatory molecules induce new bone formation. The cloning and genetic expression of recombinant human bone proteins has led to production of quantities sufficient for their clinical development. Preclinical studies have shown that the osteoinductive capacity of autograft and allograft bone can be improved with the addition of osteogenic proteins. Although these proteins are effective alone, their use with cancellous and cortical allograft and autograft consistently improved the amount and rate of new bone formation compared with graft alone resulting in earlier graft incorporation and consolidation. When placed in defects adjacent to porous acetabular components, the use of an osteogenic protein resulted in earlier defect healing and improved component fixation by the enhancement of bone ongrowth and ingrowth. Although no detailed clinical studies have been reported to date, an anecdotal report of their use with and without bone graft indicate results consistent with those obtained in preclinical studies.