Mechanical characterization of regenerated osseous tissue during callotasis and its related biological phenomenon

The mechanical characteristics of the regenerated osseous tissue and osteob lastic activities during callotasis were studied using Chinese mountain goa t as the animal model. Open osteotomy of the left tibiae was done in 24 goa ts. Distraction started 6 days after the operation with the rate of 1 mm pe r day for 4 weeks. The bone regeneration was monitored with serial X-ray fi lms. The tension generated during distraction was measured with the strain gauges mounted on the distraction apparatus. The osteoblastic activities we re monitored by measuring plasma bone specific alkaline phosphatase activit y. The results showed that the average lengthening was 22.9 +/- 2.8 mm in e ach animal. The newly formed osseous tissue becomes stiffer during the cour se of distraction lengthening. The continuous evolution of the tensile beha viour of the newly formed osseous tissue correlates with the plasma bone sp ecific alkaline phosphatase activities. The radiological appearance of a ph ysis like structure took place at 12 mm lengthening. Its appearance corresp onds to the:changes in the tensile behaviour as well as the biological acti vities of the osteoblasts and may serve as a useful radiological marker in monitoring the process of callotasis in clinical practice.