Objective To investigate the therapeutic effects of the groin skin and iliac bone composite graft on the repair of severe contracture of the first web space and one-stage reconstruction of the pollicis opponens function under the condition of no ideal muscle or tendon used. Methods From July 2003 to February 2006, 5 patients (4 males, 1 females; age range, 2038 years) with severe contracture of the first web space with loss of the pollicis opponens function were treated by the groin skin and iliac bone composite graft, with the clinical observation performed. The defect was caused by a crush injury in 3 patients, by an explosion injury in 1 patient, and by awrist joint mutilation injury in 1 patient. They all had been treated by operation at least once with a disease course of 6-24 months. The width and the angle of the first web space was 18 mm and 20° on average. Results The followed-up for 612 moths revealed that all the flaps had a success. The pedicle of the groin skin and iliac bone composite graft was cut off after 3 weeks, and 8 weeks later there was a bone union between the imbedded bone block and the first and second metacarpal bones. There was no evidence that the imbedded bone block was deformed or absorbed. The width of the first web space was augmented by an average of 32 mm, the angle of the first web space was augmented by an average of 60°. The pollicis opponens function recovered. Conclusion It is relatively simple and reliable to repair the contracture of the first web space and reconstruct the pollicis opponens function in one-stage usingthe groin skin and iliac bone composite graft.