Objective:To explore the feasibility and clinical effectiveness of preoperative positioning grid combined with CTA assisted design of anterolateral thigh perforator flap (ALTPF) in reconstruction of soft tissue defects around foot and ankle.Methods:From May 2018 to December 2021, a total of 18 cases with soft tissue defects around foot and ankle were admitted to the Department of Plastic and Reconstructive Surgery, First Affiliated Hospital of Ningbo University. The patients were 11 males and 7 females, aged from 32 to 78 years old, with an average age of 57.5 years old. Among them, 10 had chronic ulcer wounds, 6 had traumatic wounds, and 2 had postoperative wounds after malignant tumor resection. The sizes of soft tissue defect ranged from 6.0 cm×8.0 cm to 9.0 cm×13.0 cm, and the flap sizes ranged from 8.0 cm×10.0 cm to 11.0 cm×15.0 cm. Preoperative positioning grid combined with CTA three-dimensional reconstruction were used to mark the exit point of the perforator vessels in digital format, in order to restore the course of vessels and calculate the length of the vascular pedicles. ALTPFs were accurately designed based on the digitally reconstructed images, and then the ALTPFs were used to repair the soft tissue defects around the ankle. The flap donor sites were directly closed in stage Ⅰ. After the operation, all the patients were included in scheduled follow-ups at the outpatient department to observe the appearance of the recipient flaps and donor sites. The functional evaluation of the affected feet were assessed according to the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score.Results:All 18 flaps survived, and the wounds in both the recipient and donor sites healed in stageⅠ. Postoperative follow-up for the 18 patients were 5 to 36 months, with an average of 13 months. At the last follow-up, the appearances of the flaps were good without swelling, the donor sites had good recovery, and there was no obvious scar hypertrophy. The function evaluation of the affected feet were found at excellent in 10 cases, good in 6 cases, and fair in 2 cases.Conclusion:Preoperative position grid combined with CTA three-dimensional reconstruction can digitally mark the exit points and running courses of the perforator vessels. It is an effective method for accurate position of perforator vessels before surgery. It can effectively reduce the operation time, lower the surgical risks, and achieve a high survival rate of the flap, thus holding considerable clinical value.