Objective To explore effectiveness of minimally invasive internal fixation with locking plates for mid-shaft clavicle fractures. Methods Between October 2022 and August 2023, 28 patients with mid-shaft clavicle fractures were treated by minimally invasive internal fixation with locking plates. There were 10 males and 18 females with a mean age of 46.2 years (range, 18-74 years). The fractures were caused by traffic accident in 16 patients, sports-related injury in 7 patients, and other injuries in 5 patients. According to Robinson classification, the fractures were classified as type 2A1 in 1 case, type 2A2 in 6 cases, type 2B1 in 15 cases, and type 2B2 in 6 cases. The interval between fracture and operation ranged from 5 hours to 21 days (median, 1.0 days). The pain visual analogue scale (VAS) score was 8.1±1.6. The VAS score at 3 days after operation and the occurrence of complications after operation were recorded. During follow-up, X-ray films were re-examined to observe the healing of the fracture; the shoulder joint function was evaluated according to the Constant-Murley score at 6 months, and the length of the incision scar (total length of the distal and proximal incisions) was measured. ResultsAll operations were successfully completed without any subclavian vascular or nerve damage. All incisions healed by first intention. The VAS score was 1.2±0.7 at 3 days after operation, and there was a significant difference in VAS score between pre- and post-operation (t=8.704, P<0.001). At 1 week after operation, the patient’s shoulder was basically painless, and they resumed normal life. All patients were followed up 12-20 months (mean, 13.3 months). X-ray films showed that the bone callus began to form at 2-4 months after operation (mean, 2.7 months). There was no delayed healing or non healing of the fracture, and no loosening or fracture of the internal fixators during follow-up. At 6 months after operation, the mean total incision length was 1.5 cm (range, 1.1-1.8 cm); no patient complained of numbness or paresthesia on subclavicular region or anterior chest wall. The Constant-Murley score of shoulder joint function was 93-100 (mean, 97.6). Conclusion Minimally invasive internal fixation with locking plates is a good surgical method for treating mid-shaft clavicle fractures, with simple operation, minimal trauma, good postoperative results, and high satisfaction.