Objective To evaluate the applicability of a modified U-shaped forearm flap for the repair of small-and medium-sized defects in the oral and maxillary areas to provide a reference for clinicians.Methods This study was re-viewed and approved by the Ethics Committee,and informed consent was obtained from the patients.Ten patients with small-and medium-sized defects in the oral and maxillary areas underwent surgical repair using modified U-shaped fore-arm flaps.There were 8 males and 2 females aged 43-72 years.The donor site was apposed primarily after harvesting the modified U-shaped forearm skin flap.The flaps ranged from 6 cm × 4 cm to 8 cm × 5 cm in size.Six months after the operation,hand movements(finger extension,fist clenching,wrist rotation upward and wrist rotation downward),the forearm donor site,hand sensations and the satisfaction score for the postoperative quality of the scar at the donor site were evaluated(0 to 10;0:very unattractive,10:very satisfactory).Results A total of 10 patients with modified U-shaped forearm flaps survived.One patient developed venous crisis 24 hours after surgery and survived after surgical ex-ploration.Delayed healing occurred at the donor site of the forearm in 1 patient,and the wounds at the donor site of the forearm in the other patients all healed in the first stage.One patient presented with dysesthesia in the hand 2 weeks af-ter surgery and recovered within 3 months.Six months after surgery,all patients had no limited hand movement and no paresthesia at the forearm donor site or hand.The patients were basically satisfied with the appearance of the donor site,and the average satisfaction score of the subjective questionnaire was 8.4 points.Conclusion Modified U-shaped fore-arm flaps can directly close forearm donor site wounds,which avoids surgical trauma to the secondary donor site and sig-nificantly reduces related complications.Modified U-shaped forearm flaps provide an alternative to conventional forearm flaps for the repair of small-and medium-sized defects in the oral and maxillary areas.