We describe a case of a leiomyosarcoma of the thigh, the resection of all the anterior muscular compartment, and the reanimation of knee extension, using a latissimus dorsi (LD) free flap and tendon transfer. Surgical technique and postoperative care management are described. Functional results, neuropathic pain, and range of motion (ROM) were assessed at 3 months and 12 months after discharge. A complete excision (R0) was carried out and rapid wound healing was obtained despite developing a seroma infection. The patient was able to walk without technical support nor limping at 3 months post-surgery. The patient was still in remission at 12 months follow-up, with Medical Research Council (MRC) scale assessed at 4/5 and ROM rated at 5-105°. In case of total quadriceps resection, knee extension reconstruction can be obtained with tendon transfers and reinnervated free muscular flaps. Combining these techniques could be a good strategy for rapid recovery, with optimal scarring and tissue coverage.