The Use of "Spare Parts" En Bloc Anterior Compartment Myocutaneous Free Flap to Reconstruct the Transmetatarsal Amputation Stump After Contralateral Below Knee Amputation: Report of Two Cases.

The aim of reconstruction after lower extremity amputation is to provide adequate soft tissue coverage that is compatible with prosthetics to optimize functional status. We present two cases where the anterior compartment myocutaneous free flap used in a "spare parts" fashion was valuable in preserving the length of residual limbs for patients needing simultaneous below-knee amputation (BKA) and contralateral transmetatarsal amputation (TMA). The first case involved a 48-year-old woman undergoing TMA and BKA to address bilateral lower extremity necrosis secondary to septic shock. The anterior compartment muscles were taken en bloc as a myocutaneous free flap measuring ~4 × 12 cm based on the anterior tibial artery. A standard BKA was completed with a posterior flap, and the flap was used to cover exposed metatarsals on the opposite limb. After 4 years, she had no complications or additional surgeries and was able to ambulate independently. The second case involved a 55-year-old woman undergoing BKA and TMA for bilateral lower extremity gangrene. Again, the anterior compartment muscles were taken as a myocutaneous free flap measuring ~5 × 15 cm to cover the resulting TMA defect. This patient underwent debulking at 2 and 10 weeks postoperatively, after which she had no complications at 1 year of follow-up and returned to independent ambulation. This technique provided effective soft tissue coverage and successfully preserved limb length without additional donor site morbidity. As a myocutaneous free flap, the anterior compartment muscles may effectively preserve the length of residual limbs in patients undergoing BKA and TMA, allowing for improved functional outcomes and quality of life.