Objective:To investigate the clinical effects of free posterior interosseous artery perforator flap on reconstruction of the soft tissue defects of multiple fingers in one hand.Methods:Clinical data of 9 patients with soft tissue defect of multiple fingers in one hand admitted to the Department of Hand Surgery, Yongkang Orthopedic Hospital between January 2021 and August 2023 were retrospectively studied. The patients were 7 males and 2 females, aged between 19 and 55 years old. The soft tissue defects of 2 patients with 3 fingers injury and 7 patients with 2 fingers injury were reconstructed with free posterior interosseous artery perforator flaps. The size of defects in single finger was 1.5 cm×2.5 cm-3.0 cm×4.5 cm. The size of flap was 2.5 cm×7.0 cm-3.5 cm×13.0 cm. The posterior cutaneous nerve of the forearm were sutured to the intrinsic nerve of palmar side of the 14 fingers. Donor sites in forearm were directly sutured. After discharge, regular follow-up at outpatient clinic and through WeChat interviews were conducted to observe the appearance and texture of the flaps, finger fullness, donor site function and appearance, as well as patient satisfaction. For the flaps with anastomosis of cutaneous nerve, the recovery of TPD of the flap was tested. Sensory recovery was assessed according to the British Medical Research Council (BMRC) sensory function assessment criteria. Hand functions were evaluated using the Total Active Movement (TAM) of fingers of the Hand Surgery of the Chinese Medical Association.Results:All of the 20 flaps survived and were evaluated through follow-up visits, which ranged from 6 to 25 months with an average of 13 months. The flaps were soft, unbloated and without obvious pigmentation. The protective sensations were recovered with an average static TPD of 14 flaps anastomosed with cutaneous nerve was of 9.7 (7-13) mm. Among them, S 3+ 10 fingers, S 3 4 fingers; 6 fingers of flap without sutured cutaneous nerve, S 2 5 fingers, S 1 1 finger. According to the TAM of Hand Surgery of Chinese Medical Association, the results were excellent for 15 fingers and good for 5 fingers. There was no scar contracture in the forearm donor sites and motor function was not affected. Conclusion:Posterior interosseous artery perforator flap has the advantages of thin flap, similar texture to the hand, good recovery in sensory, and minimal damage to the donor site. Therefore, it is a good option in reconstruction of soft tissue defects of multiple fingers in one hand.