Modified Lateral Approach to the Anterior Tibial Artery's Origin With Limited Fibular Resection: A Case Report of Free Flap Reconstruction for Lateral Skin Defects in Single-vessel Lower Extremities.

In free flap surgery for open fractures of the lower leg, selecting recipient vessels can be difficult when multiple vessels are injured. In single-vessel lower extremities, surgeons must choose between using the remaining vessel and a proximal site of an injured one. However, using the remaining vessel risks ischemia and below-knee amputation if complications arise. The proximal site of the anterior tibial artery (ATA) can be exposed using the lateral approach to the tibioperoneal trunk. However, this approach is rarely used because fibular head resection may cause postoperative lateral collateral ligament dysfunction. To overcome this problem, we developed a modified lateral approach that preserved the fibular head. Herein, we present a case of a single-vessel lower extremity with an intact posterior tibial artery and a lateral skin defect, requiring the proximal site of the ATA as a recipient vessel. In our modified lateral approach, the tibioperoneal trunk and ATA's origin were exposed similarly to the traditional method. Although a short portion of the ATA was visible before osteotomy, limited resection of the proximal fibula (with the fibular head preserved) improved exposure of the proximal ATA. The vessel's condition was confirmed via adequate bleeding following its incision. A free latissimus dorsi flap was transferred using an end-to-end anastomosis. At the 10-month follow-up, the flap survived without necrosis, and stress radiography of the knee revealed no varus instability. To the best of our knowledge, this is the first report of a modified lateral approach to the ATA's origin, which resolved postoperative knee instability.