Unconventional Combination of Thigh Flaps for Large Knee Defect Reconstruction After Sarcoma Resection: A Case Report

Reconstructing large knee defects after sarcoma resection poses a significant surgical challenge, particularly when vascular anatomy variations or intraoperative vessel damage limit conventional reconstructive options. Achieving stable, tension-free coverage while preserving mobility is essential for optimal functional outcomes. We report the case of a 45-year-old male patient who underwent radical resection of a distal thigh myxofibrosarcoma, resulting in a large defect (24 × 18 cm) over the anterior knee region. A distally based anterolateral thigh (ALT) flap with two skin paddles was initially planned in order to achieve a "kissing" flap inset. However, intraoperative findings revealed that the distal part of the descending branch of the lateral circumflex femoral artery (DB-LCFA) had been compromised, necessitating modifications to the reconstruction strategy. The distal ALT skin paddle was utilized as a pedicled propeller flap, while the proximal ALT skin paddle, which had a separate vascular supply, was harvested as a free flap and anastomosed to a distal perforator from the DB-LCFA in a perforator-to-perforator fashion. Despite this approach, a significant residual defect remained. To achieve complete coverage, we performed an additional free flap using a vertical posterior medial thigh (vPMT) flap from the contralateral thigh, anastomosed to perforator vessels from the genicular artery. This case highlights the necessity of intraoperative adaptability when managing large oncologic defects, especially in the presence of vascular compromise. The combination of pedicled and free flaps, including an unconventional ALT flap configuration and a secondary vPMT flap, provided a stable, functional, and esthetically satisfactory outcome. Strategic integration of perforator-based techniques and intraoperative imaging optimized flap viability, demonstrating a reliable approach for complex lower limb reconstructions.