The effect of external skeletal fixation on bone healing and bone blood supply. An experimental study.

The effect of external skeletal fixation on blood supply and healing of the tibia was investigated in the New Zealand white rabbit. Bilateral osteotomies were made in ten rabbits. One osteotomy was stabilized with a small unilateral external fixator and the other with a conventional long-leg cast. The animals were killed at various intervals from one to ten weeks. Microsphere infusions indicated a greater blood supply in the cast-treated osteotomies after five weeks. Histologic examination showed that external fixation alters the proportions of periosteal and medullary ossification in the healing process. External fixation decreased the periosteal response but seemed to enhance both the endochondral ossification of callus and medullary ossification.