USE OF AN OSTEOINDUCTIVE BIOMATERIAL (RHOP-1) IN HEALING LARGE SEGMENTAL BONE DEFECTS

Objective: To assess the radiographic, histologic, and mechanical char acteristics of new bone formation in large segmental bone defects trea ted with a new osteoconductive material, recombinant human osteogenic protein-1 (rhOP-1). Design: In vivo animal study. Intervention: Sixtee n dogs (thirty-two limbs) with an ulna segmental defect (2.5 centimete rs) were randomized to three treatment groups: rhOP-1, collagen alone, and no implant. Main Outcome Measurements: Radiographic evidence of d efect healing, mechanical testing (torsional strength) as compared wit h thirty-one control intact dog ulnas, and histologic analysis. Result s: At twelve weeks, complete radiographic healing was observed in twen ty-five of twenty-eight defects (89 percent) treated with rhOP-1. The mechanical strength of the rhOP-1-treated defects at twelve weeks was 65 percent of that of intact ulnas. Histologic analysis revealed that defects treated with rhOP-1 were bridged with lamellar and woven bone that was in continuity with the host bone. Conclusions: The results in dicate that osteoinductive materials, which have the ability to quickl y fill and heal large defects, may have advantages over osteoconductiv e materials, which are typically used to fill smaller non-load-bearing bone voids.