Wide resection of the lateral malleolus and adjacent tibial, talar and calcanear bones with ankle fusion and allograft reconstruction for an osteosarcoma.

Introduction: Primary bone sarcomas around the ankle are rare. Due to the proximity of neurovascular structures and limited soft tissue reserves, limb salvage is often not possible. Case report: A 19 yo male presented with pain and a progressive swelling of his ankle. X-rays revealed cortical erosions and an extensive periosteal reaction (sunburst) of the distal fibula. MRI showed a large mass of the fibula invading adjacent soft tissue. The lesion appeared close to the ankle joint, but with the articular cartilage as a barrier and without joint effusion. Core-needle biopsy revealed a high-grade chondroblastic osteosarcoma. No metastases were detected. After presentation at our multidisciplinary sarcoma board, the patient was subjected to neo-adjuvant chemotherapy (AOST 03-331). Without any sign of intra-articular contamination of the ankle joint, surgical treatment consisted of wide resection of the lateral malleolus including a large skin patch, the distal third of the fibula, the lateral surfaces of the tibia and talus as well as the insertion of the lateral ligament on the calcaneus. The distal parts of the anterior, peroneal, and posterior muscular compartments were resected en bloc with the tumor. The defect was reconstructed with tibio-talar and talo-calcanear fusion, bony allograft and a plate. Soft-tissue coverage was achieved with a free fascio-cutaneous flap from the controlateral thigh. Histological analysis revealed clear margins and 50% of tumor necrosis. The oncologic treatment was completed with adjuvant chemotherapy. Conclusion: Wide resection and reconstruction of the lateral malleolus is technically demanding but possible in selected cases. Despite some important functional loss, limb salvage is superior to an amputation.