Histological and radiological analysis of autoclaved bone 2 years after extirpation

We examined grafted distal femoral autoclaved bone radiologically and histologically 24 months after surgery. The patient was a 16-year-old boy with osteoblastic-type osteosarcoma in the distal part of the left femur. The patient received pre- and postoperative chemotherapy and underwent limb reconstruction surgery using an autoclaved autograft. He was forced to undergo hip disarticulation because of local recurrence in the soft tissue. Radiologically and histologically, we were able to detect newly formed bone at the site of the distal junction and surrounding the autoclaved autograft, although most of the autoclaved bone remained without substitution even 24 months after implantation. The layer of newly formed bone surrounding the autoclaved autograft was so thin that it seemed to be ineffective for weight-bearing. Drilling into the autoclaved autograft appeared to promote little bone regeneration inside the autoclaved autograft. A bone scintigram showed newly formed bone around the autoclaved autograft, but the scan tended to exaggerate such bone formation beyond that actually confirmed by histological examination. We should be careful when applying autoclaved bone for weight-bearing parts.