We compared delayed distraction (DD) with immediate distraction (ID) in bone-lengthening. Open femoral diaphyseal osteotomy was performed on 24 three-month-old lambs, and external distractor fixators were applied. In the ID group (n 12), distraction commenced on the first postoperative day; in the DD group (n 12), distraction was delayed until the tenth day after surgery. In all the animals, the femur was lengthened by 2 cm at the rate of 1 mm/day. The animals were killed 1, 2, and 3 months postoperatively. Radiography and densitometry of the lengthened callus showed that DD, compared with ID, improved the quality of the callus with quicker, denser, and more homogeneous bone formation.

No abstract