Skin necrosis after total knee arthroplasty is a rare complication that can rapidly lead to deep infection of the prosthetic components. The medial gastrocnemius transposition flap usually provides adequate soft tissue coverage to salvage the total knee arthroplasty. However, variations in defect location and excursion of the muscle flap can affect results. Twelve patients were treated with a medial gastrocnemius transposition flap after total knee arthroplasty. The skin defect that required flap coverage was located over the tibial tubercle or patellar tendon in eight patients (Group 1). The defect extended proximally to the patella or quadriceps tendon in four patients (Group 2). A functioning total knee arthroplasty was salvaged in 11 patients (92%). The medial gastrocnemius flap healed primarily in all patients in Group 1. Three patients in Group 2 required additional fasciocutaneous, lateral gastrocnemius, or free flap coverage, and one patient underwent above knee amputation. The medial gastrocnemius flap is most effective for coverage of distal defects over the tibial tubercle or patellar tendon. Defects that extend more proximally over the patella or quadriceps tendon are more likely to require additional procedures to achieve adequate soft tissue coverage. METHODS Therapeutic study, level IV (case series). See Author Guidelines for a complete description of levels of evidence.