Abstract: Objective To investigate the clinical effect of small incision osteotomy via palmar approach combined with external fixator with bone cement in the treatment of malunion of the fifth metacarpal neck fracture. 
 Methods Small incision osteotomy via palmar approach combined with external fixator with bone cement was used to treat 27 patients with malunion of the fifth metacarpal neck fracture. Through follow-up for more than 6 months after operation, the appearance index, functional index and overall satisfaction of the patients were evaluated. 
 Results The duration of follow-up was 6-12 months, with an average of (8.6±2.1) months. All patients achieved bony union at 8-21 weeks after operation, without complications such as fracture of internal fixation, deep wound infection or nonunion of fracture. The length of the fifth metacarpal bone, the extension angle of the metacarpophalangeal joint, the range of motion of the fifth metacarpophalangeal joint, the pinch force and the grip strength of the thumb and little finger, and patient satisfaction score after the operation were significantly better than those before operation (P＜0.05). 
 Conclusion Small incision osteotomy via palmar approach combined with external fixator with bone cement for the treatment of malunion of the fifth metacarpal neck fracture is a safe and effective method, which greatly improves the appearance and function of the patient's hand, and is worthy of clinical promotion. 

Key words: metacarpal bones, fractures, malunited, osteotomy, external fixatorwith bone cement