The origin of osteoprogenitor cells responsible for heterotopic ossification following hip surgery: an animal model in the rabbit

Purpose. To investigate the source of osteoprogenitor cells responsible for heterotopic ossification (HO) following total hip arthroplasty in an animal model. Methods. New Zealand White (NZW) rabbits ( n=20) received a radiation treatment 24 h preoperatively to the hip joint of one hindquarter and to the femoral shaft of the contralateral side. Subjects underwent bilateral hip surgery 24 h after treatment. Subjects were euthanized and radiographed 4 months postoperatively. Heterotopic ossification was graded according to a modified Brooker scale. Mean grade, intra-observer reliability, and statistical significance ( p