Objective To explore the efficacy of transplantation of a U-shaped ilioinguinal flap in the re pair of skin and soft tissue defects of the extremity.An axial flap based on the superficial iliac circumflex artery and trimmed to a subdermal vascular network flap was used for the procedures.Methods Seven patients with skin and soft tissue defects treated between June,2009 and May,2014 were studied.The patients were 22-45 years of age (mean,32 years),and included 5 males and 2 females.Four patients had punch-press injuries,1 patient had a hot-crush injury,and the remaining 2 patients were injured in the accidents.The wound sizes were 14.0 cm × 10.0 cm to 6.0 cm × 5.0 cm,with a varying extent of exposed tendons and bones.Repairs were performed using free ilioinguinal flaps,which were 15.0 cm × 11.0 cm to 7.0 cm × 5.0 cm in size.The axial flap was trimmed to a U-shaped subdermal vascular network flap and transplanted to the recipient site with anastomosis of blood vessels.Results All transplanted flaps survived.Four patients were followed for 1-6 months,with a mean duration of follow-up of 4 months.The trimmed flaps showed gradual reddening immediately after surgery,and the capillaries were recovered with a flat surface.Re-examination 3 months after surgery showed that the flaps were thin and flexible and met the aesthetic demand.No obvious pigmentation occurred,and the donor site was sutured directly,leaving only linear scars.Conclusion Repair of skin and soft tissue defects of the extremity using a U-shaped trimmed ilioinguinal flap has the advantages of a hidden donor site,small scar,and conformity to aesthetic requirements.The trimmed flaps are preferred over untrimmed flaps in terms of color and texture.The former flap is thinner,meets the aesthetic demand,and achieves a better efficacy.