Osteogenesis within polyethylene implants at fracture gaps.

Sterile 7 mm. polyethylene implants were implanted in standard 6 mm. bilateral midfibular fracture gaps in thirty rats (sixty defects), and six rats were used as controls with identical bilateral midfibular fracture gaps. Clinical, radiologic, and histologic studies at a 12-week interval revealed osteogenesis at internal and external surfaces of implants resulting in bony union; however, gaps without implants resulted in fibrous union and nonunion.