Objective:To investigate the clinical effect of bilateral anteriolateral thigh perforator flaps (ALTPF) pedicled with descending branch of lateral circumflex femoral artery in series on reconstruction of large soft tissue defects in lower limbs.Methods:A total of 9 patients with large soft tissue defects in lower limbs were selected in the study. The patients were 6 males and 3 females aged between 18 and 57 years old. They were treated in the Department of Hand and Foot Microsurgery, the Affiliated Hospital of Qingdao University from June 2018 to January 2023. Causes of injury: 4 of traffic accident, 2 of crushing, 2 of falling from height and 1 of explosion. Five patients had combined defects in dorsal feet and 4 with tibia fractures and anterior-and-posterior-tibial soft tissue defects. All affected limbs had tissue necroses and infections in various degrees. Deep tissue defects such as tendons, nerves, bones and joints or orthopaedic implants were exposed. The areas of soft tissue defects were 30 cm×14 cm-42 cm×14 cm. All the defects were reconstructed by the bilateral ALTPF pedicled with descending branch of lateral circumflex femoral artery in series. The size of proximal flaps was 25 cm×8 cm-33 cm×13 cm and 20 cm×7 cm-29 cm×13 cm for the distal flaps. Scheduled postoperative follow-ups were conducted to observe the survival of the transferred flaps and functional recovery of calfs and feet. Sensory recovery was assessed against British Medical Research Council (BMRC) criteria. Puno scoring was used to assess the functional recovery and the effectiveness of treatment.Results:All flaps survived and the donor sites healed well. One patient developed vascular compromise within 24 hours after surgery, but it was rectified after timely surgical exploration, however it left with a small area of necrosis at distal end of the flap. The necrosis and wound healed after skin grafting in stage-two surgery. Postoperative follow-up lasted for 8.3 months in average. Two patients underwent flap thinning in stage-two surgery due to bloating appearance, 2 patients had slightly bloated flaps at the calfs, and the rest of 5 patients had satisfactory flap appearance. Two patients received nerve reconstruction by anastomosis of the lateral femoral cutaneous nerves. At the final follow-up, the sensory recovery in 9 patients achieved S 2-S 3+ according to BMRC. The average Puno score achieved 88.36 point±5.36 point, of which 4 patients in excellent, 3 in good and 2 in fair. Conclusion:The use of bilateral ALTPF pedicled with descending branch of lateral circumflex femoral artery in series to reconstruct a large soft tissue defect in lower extremity has a good clinical value, and it has become one of the effective methods.