Osteoinduction in rhesus monkeys using demineralized bone powder allografts

This experiment tested the osteoinductivity of demineralized bone powder (DBP) in nonhuman primates. Six DBP implants were implanted subcutaneously close to the pectoralis major muscle in each of four rhesus monkeys. Excisional biopsies were obtained 20, 40, and 72 days after implantation and were processed for light and electron microscopy. Decalcified and undecalcified sections of the implants were studied. Large numbers of undifferentiated mesenchymal and fibroblast-like cells were observed around and within the DBP matrix particles on day 20. Cartilage formation was also evident at that time and had increased by day 40, when chondroid bone also appeared. By day 72, the implants showed mature (lamellar) and immature (woven and chondroid) bone and bone marrow formation. Areas of DBP that were incorporated within the induced bone contained empty lacunae and stained similarly to mineralized bone. It was concluded that allogenic DBP can induce bone formation in monkeys. The results justify the use of DBP as a bone-banked material to induce bone formation in humans.