TREATMENT OF SEGMENTAL DEFECTS IN LONG BONES USING OSTEOPROMOTIVE MEMBRANES AND RECOMBINANT HUMAN BONE MORPHOGENETIC PROTEIN-2 - AN EXPERIMENTAL-STUDY IN RABBITS

The purpose of this study was to investigate whether barrier membranes that were earlier shown to promote bone healing in the craniofacial s keleton are capable of producing bone healing in long bone defects by themselves or in combination with recombinant human bone morphogenetic protein 2 (rhBMP-2). Segmental defects (10 mm long) in the rabbit rad ius, known to heal as pseudoarthrosis-like defects, were used as the e xperimental model. Treatment with expanded polytetrafluoroethylene mem branes (GORE-TEX(R) Membrane) (n = 10) resulted in only minor amounts of bone formation within the defect and collapse of the membranes was common. When placement of membranes was combined with implantation of rhBMP-2 in a beaded biodegradable copolymeric PLA/PGA carrier, total b ony bridging of the defects was accomplished within 10 weeks (n = 5). Osteopromotive membranes combined with rhBMP-2 can therefore bring abo ut complete healing of long bones. The membranes exclude soft tissue f rom the defect and at the same time keep the growth-stimulatory implan t in place and maintain the anatomical contour of the bone. The combin ation of osteopromotive membranes and rhBMP-2 may be of value in recon structive bone surgery.