Vascularized Ulna Graft in the Rat

When a vascularized fibula graft was performed for a bone defect in the extremity long bones, significant hypertrophy was observed when the graft was transferred to a mechanically loaded lower extremity, but less hypertrophy was observed when it was transfered to the upper extremities. This phenomenon of hypertrophy is related to the imposed mechanical stress load [1–3]. We designed a murine experiment to clarify the etiology of postoperative hypertrophy of vascularized bone grafts. We performed syngeneic vascularized ulna transfer to a segmental bone defect in the rat, with or without mechanical loading. The bone dynamics of the grafts were examined by fluarochrome bone labeling and histomorphological measurement.