Objective To explore the feasibility and effectiveness of repairing surgical defect in pharyngo-laryngeal malignant cancer with free rectus femoris flap. MethodsThe clinical data of 34 patients with surgical defects in pharyngo-laryngeal malignant cancer who met the selection criteria between July 2014 and August 2024 were retrospectively analyzed. There were 25 males and 9 females, aged 25-82 years, with a median age of 54 years. The disease duration ranged from 2 months to 2 years, with a median of 7 months. The tumor locations included the oropharynx, hypopharynx, cervical esophagus, and larynx. Pathological types included squamous cell carcinoma (29 cases), myoepithelial carcinoma (2 cases), adenoid cystic carcinoma (1 case) and diffuse large B-cell lymphoma (2 cases). TNM staging: 16 cases of T4N1M0, 3 cases of T4N2M0, 3 cases of T4N0M0, 10 cases of T3N1M0, and 2 cases of T3N0M0. The 2017 American Joint Committee on Cancer (AJCC) staging was stage III in 2 cases and stage IV in 32 cases. The blood supply of the proximal rectus femoris muscle was observed by enhanced CT of the lower limb vessels before operation, and the surgical defects ranged from 3.0 cm×2.0 cm to 12.0 cm×8.5 cm. The blood supply and perforators of rectus femoris muscle were explored during operation, and the free rectus femoris flap pedicled with the direct vascular stem of rectus femoris muscle was used to repair the defect. For the patients with pharyngeal fistula or obvious neck swelling after operation, the blood supply of the flap was analyzed by vascular enhanced CT to determine the corresponding strategies of nutritional support, anti-infection, dressing change and drainage. Radiotherapy and chemotherapy were supplemented in 27 patients with lymph node metastasis after operation. Results All the 34 patients were followed up1-10 years, with an average of 3 years. The flap was found to be necrotic by fibrolaryngoscopy at 1 week after operation in 2 cases, and the incision healed after dressing change and nutritional support, and no reoperation was performed. The flap was in good condition at 1 week after operation in 4 cases, and the signs of gradual necrosis of the flap were found within 1 month after operation, of which 2 cases were healed after dressing change, 1 case was removed the necrotic tissue by reoperation, and 1 case was healed after pectoralis major myocutaneous flap was used to repair the pharyngeal tissue defect. The flaps survived in 28 cases, including 4 cases of pharyngeal fistula, which were healed by dressing change. Twenty-two cases achieved satisfactory results in swallowing or phonation. Two patients with total laryngectomy and voice reconstruction underwent reoperation to seal the voice tube because of postoperative aspiration. During the follow-up, 1 case had fistula recurrence, 2 cases had bone metastasis, and 1 case had bone and lung metastasis. Conclusion The free rectus femoris flap has good flexibility, the volume of the flap is easy to adjust, and the incision of the donor site is concealed, which is expected to become a new choice for the repair of the surgical defect in pharyngo-laryngeal malignant cancer.