A 9-year-old male presented after a traffic accident with a complex post-traumatic defect in the left foot and ankle including a 7 x 10 cm loss of substance with exposure of the tibial malleolus, talus and subtalar joint, section of the posterior tibial tendon and long flexor tendon of the toes and avulsion of the tibial nerve and posterior tibial artery with a defect of 5 cm. The foot remains vascularised through the anterior tibial artery.

After the relevant debridement of devitalised tissue, reconstruction of the defect was considered 5 days after the trauma, by repairing the affected tendons, reconstructing the tibial nerve with sural nerve grafts and covering the defect with an ALM perforator flap. Preoperatively a 7 x 10 cm flap is designed on the left thigh based on a localised perforator with Doppler. After a standard subfascial dissection of the flap following the description made by Wei et al. (4), we located a perforator with a very long intramuscular course and small diameter; it was then decided to explore proximally the transverse branch of the lateral femoral circumflex artery (LFA) in order to look for a better perforator. A larger caliber perforator is located at that level and the flap is redesigned to become a TFL perforator flap, drawing a skin island more proximally with centre at the new perforator; the lateral femorocutaneous nerve of the thigh is included in the flap to provide sensation. After repair of the tibial nerve with 3 sural nerve grafts of 5cm each, transfer and fixation of the flap is performed. Anastomoses are made termino-terminally to the posterior tibial artery and to two veins, a posterior tibial comitant vein and the great saphenous vein. The lateral femorocutaneous nerve of the flap is connected termino-laterally to the proximal end of the tibial nerve. Finally, a direct closure of the donor site is performed. The total operative time was 7 hours and 30 minutes. The postoperative period was uneventful and the patient was discharged from hospital 18 days after surgery.

The physiotherapy programme started from the first postoperative week, with partial foot support (with the aid of crutches and a protective splint) one month after surgery and full foot support for ambulation at 6 weeks. At 4 months after surgery the foot contour was adequate, allowing the patient to wear normal footwear, with a range of ankle mobility of 45º of plantar flexion and 15º of dorsal flexion and a protective sensitivity (detected with monofilament test) of the plantar and flap.