[Clinical effects of free hallux-nail flap combined with the second toe composite tissue flap in the reconstruction of damaged thumb after electrical burns].

To explore the clinical effects of free hallux-nail flap combined with the second toe composite tissue flap in the reconstruction of damaged thumb after electrical burns. A retrospective observational study was conducted. From May 2018 to April 2021, 12 male patients with thumb destructive defects caused by electrical burns who met the inclusion criteria were admitted to Zhengzhou First People's Hospital, aged 27 to 58 years, including 10 cases with degree Ⅲ thumb defect and 2 cases with degree Ⅳ thumb defect after thorough debridement. The thumb was reconstructed with free hallux-nail flap combined with composite tissue flap of the second phalangeal bone, joint, and tendon with skin island. The donor site of hallux-nail flap was covered with artificial dermis in the first stage and performed with continuous vacuum sealing drainage, and covered with medium-thickness skin graft from the groin site in the second stage. The donor site in the second toe was filled and fixed with iliac bone strips. The survival of reconstructed thumb was observed 1 week after the reconstruction surgery, the survival of skin graft in the donor site of hallux-nail flap was observed 2 weeks after skin grafting, and the callus formation of the reconstructed thumb phalanx and the second toe of the donor foot was observed by X-ray 6 weeks after the reconstruction surgery. During the follow-up, the shape of reconstructed thumb was observed and the sensory function was evaluated; the function of reconstructed thumb was evaluated with trial standard for the evaluation of the functions of the upper limbs of the Hand Surgery Society of the Chinese Medical Association; whether the interphalangeal joints of the hallux and the second toe were stiff, the scar hyperplasia of the foot donor site, and whether the walking and standing functions of the donor feet were limited were observed. One week after the reconstruction surgery, all the reconstructed thumbs of the patients survived. Two weeks after skin grafting, the skin grafts in the donor site of hallux-nail flap of 11 patients survived, while the skin graft in the donor site of hallux-nail flap of 1 patient was partially necrotic, which was healed completely after 10 days' dressing change. Six weeks after the reconstruction surgery, callus formation was observed in the reconstructed thumb and the second toe of the donor foot of 10 patients, the Kirschner wires were removed; while callus formation of the reconstructed thumb was poor in 2 patients, and the Kirschner wires were removed after 2 weeks of delay. During the follow-up of 6 to 24 months, the shape of reconstructed thumb was similar to that of the healthy thumb, the discrimination distance between the two points of the reconstructed thumb was 7 to 11 mm, and the functional evaluation results were excellent in 4 cases, good in 6 cases, and fair in 2 cases. The interphalangeal joints of the hallux and the second toe of the donor foot were stiff, mild scar hyperplasia was left in the donor site of foot, and the standing and walking functions of the donor foot were not significantly limited. The application of free hallux-nail flap combined with the second toe composite tissue flap in the reconstruction of damaged thumb after electrical burns adopts the concept of reconstruction instead of repair to close the wound. It can restore the shape and function of the damaged thumb without causing great damage to the donor foot.