Double Vascularized Fibulas for Reconstruction of Large Tibial Defects

ABSTRACT

Vascularized fibular grafts have proven to have many advantages over nonvascularized transplants for treatment of large segmental bone defects in the extremities. Fibulas are typically impacted into the medullary canal and fixed with wires or screws. Consolidation has often been delayed and full weightbearing was only possible after graft hypertrophy, usually 12 to 18 months after reconstruction. In order to shorten the time of consolidation and to achieve early full weightbearing, the authors propose a sound biomechanical reconstructive concept: a) stable but not devascularizing osteosynthesis of the osteotomy to shorten the time of consolidation; b) a doublestrut fibular graft that yields enough strength for early weightbearing, without the need for bone hypertrophy; and c) additional cancellous bone grafts, to enhance the long-term stability of the reconstruction.

Seven patients with tibial defects ranging between 6 and 17.5 cm were treated according to this concept. In four cases, free vascularized fibula was transferred first. Six weeks later, a vascularized, ipsilateral fibula-pro-tibia procedure was done, and the space between the fibulas was filled with cancellous bone grafts. In three patients, a free, vascularized, double-barrel, fibula transfer was done, since the tibial defect was less than 10 cm. Cancellous bone grafts between the fibulas were added only 6 weeks later. In five cases, the free fibula transfer was combined with a latissimus dorsi myocutaneous flap.

In six patients, healing was uneventful. In one patient, hypoperfusion of the lower extremity and the vascularized grafts eventually resulted in a below-knee amputation.

In all six successful cases, union resulted within 3 months. Full weightbearing, without orthosis or crutches, was possible within 5 to 6 months. Radiologically, dense bone formation resulted after cancellous bone grafting, that bound the fibulas into a unique reconstruction. No stress fractures have been observed. Vascularized fibular grafts, in combination with latissimus dorsi myocutaneous flaps, provide abundant tissue for repair of major bone and soft-tissue defects. Skin islands on the vascularized bone grafts help monitor the circulation.