Intercalary Allograft to Reconstruct Large-Segment Diaphysis Defects After Resection of Lower Extremity Malignant Bone Tumor

AIM: To evaluate the clinical effect of intercalary allograft transplantation and reconstruction in the treatment of diaphyseal defect after resection of lower extremity malignant bone tumor. METHODS: Clinical data of 17 patients diagnosed with malignant lower-limb bone tumors and having undergone segmental allograft reconstruction with a mean follow-up of 49.8 (26–78) months were included. Segmental allografts of average 17-cm length preserved by deep-freezing were used and fixed using intramedullary nail, double plate, and intramedullary nail and plate combination in 2, 5, and 10 patients, respectively. Host–donor junctions were perfectly and roughly matched in 5 and 12 patients, respectively. Allograft union, local recurrence, and complications were assessed using clinical and radiological tests. Allograft union was evaluated using the International Society of Limb Salvage (ISOLS) scoring system. The functional prognosis was evaluated using the Musculoskeletal Tumour Society (MSTS) scoring system. RESULTS: Intercalary allograft reconstruction of femoral shaft, tibial shaft, and distal tibia with ankle arthrodesis was performed in eight, four, and five patients, respectively. Two patients had local recurrence and underwent amputation; one died of metastasis. Host–donor junctions in two patients showed nonunion; 12 patients achieved bone union. The average union time was 12.1 months. No allograft fracture or infection occurred. Union rates were 100% and 88.2% at metaphyseal and diaphyseal junctions, respectively. Healing time differed significantly between the precisely and roughly matched groups (p<0.01). The incidence of nonunion was higher after intramedullary nailing than after the other two methods (p<0.05). The mean MSTS score was 24.2 (14–29) at the end of follow-up. CONCLUSION: Intercalary allograft transplantation is an effective strategy for diaphyseal defect following post-tumor resection in the lower extremity. Good bone healing after allograft reconstruction is achieved with stable internal fixation and perfectly matched host–donor interfaces.