Optimizing the use of local muscle flaps for knee megaprosthesis coverage

Primary muscle flap cover of megaprostheses following limb salvage surgery for tumors around the knee serves to decrease infection rates, provide additional soft tissue cover over the implant, and act as a bed for split-skin grafting. The purpose of this study is to demonstrate the role of supplementary muscle flaps such as the hemisoleus, gracilis, and semimembranosus in augmenting coverage provided by gastrocnemius muscle flaps. Between August 1999 and August 2006, 10 patients underwent resection of distal femur (n = 5) or proximal tibia (n = 5) sarcomas, followed by bone reconstruction with a modular megaprosthesis and soft tissue coverage with local pedicled flaps. The average age was 31 years (range, 13 to 47), with pathologic diagnoses inclusive of osteosarcoma (n = 7), chondrosarcoma (n = 2), and recurrent giant cell tumor (n = 1). For proximal tibial tumors, both bellies of the gastrocnemius with hemisoleus for additional soft tissue cover were used. For distal femoral tumors, 1 gastrocnemius belly sutured to the extensor mechanism and gracilis or semimembranosus provided adequate soft tissue cover. All flaps survived without complications, all wounds healed well, and all patients were ambulant after surgery. The role of supplementary muscle flaps was demonstrated in specific situations, where coverage of the subcutaneous area of the midtibia was deficient and where a significant amount of the vastus medialis or gastrocnemius has been resected. Technical refinements included primary skin grafting to relieve tension during skin closure and excision of the aponeurosis over the gastrocnemius and hemisoleus to increase the reach and surface area of the muscle flap.