Reconstruction after resection of tumors around the knee: role of the free vascularized fibular graft.

We present our experience with reconstruction after resection of tumors around the knee, using free vascularized fibular grafting. The study included 23 patients. The lower femur was involved in 17 cases, the upper tibia in 6. The cases included giant cell tumor of the lower femur (2 patients), giant cell tumor of the upper tibia (1 patient), malignant fibrous histiocytoma of the lower femur (1 patient), parosteal osteosarcoma (1 patient), and periosteal osteosarcoma (1 patient). The remaining patients suffered from conventional osteogenic sarcomas. The size of the defect ranged from 12 to 16 cm in length. Skin flap necrosis after tumor resection was the most common complication encountered. Other complications included peroneal nerve involvement in one case and rupture of the arterial anastomosis in another. All transferred fibulas progressed to union within 7-9 months. Union time of both upper and lower ends of the fibula and time of appearance of periosteal reaction were identical. In evaluating periosteal hypertrophy of the fibula, the hypertrophy (de Boer) index (de Boer HD, Wood MB, J Bone Joint Surg 1989;71B:374-378) proved unreliable. False positive results are obtained, when callus formation around the lower end of the femur is far more abundant than at the upper end of the fibula. For this reason, we introduced the graft index. The latter is the ratio between the diameter of the graft at its thinnest portion at latest follow-up to its diameter on the day of operation, as calculated on plain radiographs. Two of the viable fibulas developed stress fractures after plate removal. Functional and quality-of -life results were satisfactory. It is concluded that the free vascularized fibular graft remains a valuable reconstruction option after the resection of tumors around the knee, provided certain precautions are followed. First, before closure of the wound, the skin flaps should be assessed for their viability. Necrotic parts should be excised. Stable fixation is a necessary prerequisite at the time of operation. Removal of the fixation device should not be guided by union or periosteal hypertrophy, but by true widening of the medullary canal. Copyright 2000 Wiley-Liss, Inc.