Introduction: Limb-sparing surgery is the technique of choice for most patients with long bone sarcomas. These resections often result in large, complex tissue defects that have been traditionally repaired with avascular allografts and local tissues with mixed success. Union between allograft and the host bone usually takes place slowly and a relatively high rate of non-union often necessitates additional operations. Late fractures of the allograft usually do not heal. These shortcomings, together with the success of microsurgical techniques in reconstruction traumatic bone defects, have led to the use of vascularized fibula in the reconstruction of these challenging cases. To date, few studies have evaluated the long-term union rates of microsurgical reconstruction of extremity long bone defects resulting from tumor resection. The purpose of this study was, therefore, to evaluate bone union, functional outcome as well as patient survival in a single institution’s series of extremity reconstructions using microvascular fibula flaps.

Materials and Methods: This was a retrospective review (1991-2002) of patients reconstructed with free fibula flaps after limb sparing resection of extremity sarcomas. A detailed chart review, as well as review of data from a prospectively maintained free flap database was performed for each patient. The timing of reconstruction, patient factors, complications, distant/local metastasis, survival, and functional outcomes were analyzed.

Results: 25 flaps (20 immediate, 5 delayed) were performed in 25 patients (14M, 11F). Mean age was 25.5 years (range 5 - 74). The reconstructed areas included the tibia (9), radius (5), humerus (6), femur (4) and ulna (1). Osteosarcoma (8), Ewing’s sarcoma (8), and chondrosarcoma (6) accounted for the majority of cases. The mean bone defect was 13 cm (6-18) and mean fibula length was 17 cm (11-27). There were no flap failures and the average hospital stay was 11.1 days. One patient died two days after the surgery due to an acute asthma attack. One patient required emergent re-exploration for a venous thrombosis and was salvaged successfully. Three patients experienced postoperative infections and all healed with conservative treatment. There were no delays in postoperative adjuvant chemotherapy. Distant metastasis developed in 6 patients (24 %) after an average of 13.3 months (5-30 months). Five patients developed distant metastasis and died (mean survival 27.6 months). Local recurrence occurred in 2 patients (8%). Long term functional outcome data was available for 14 patients at an average of 53.4 months (6-117 months). In these patients the bone union rate was 78.6% (11/14) and occurred after an average of 8.4 months (4-14). 3 patients had a non-union (21.4%). Two of the three patients with non-union underwent secondary bone grafting and subsequently went on to union; therefore, the overall bone union rate was 93%. Partial (6.8 mo) and full (12.6 mo) weight bearing were permitted after adequate healing. All patients who had successful bony union (13/14) had excellent functional outcomes. In addition, long-term hypertrophy of the flap to near normal size was noted. Four patients underwent hardware removal and there were no fractures requiring surgery.

Discussion: Microvascular fibula transfer is the method of choice for reconstruction of large, complex long bone defects resulting from tumor extirpation. This is important since osteogenic sarcoma has become a curable disease in many patients. In our series most patients with long-term follow up were able to tolerate full weight bearing with some even able to participate in sports. In addition, we noted that fibula flaps underwent significant hypertrophy with time, closely approximating the size of native tibia or even femur. Vascularized fibula flaps are also an excellent alternative for salvage of failed allograft reconstruction.