Transacromial extra-articular Knowles pin fixation treatment of acute type V acromioclavicular joint injuries

Type V acromioclavicular (AC) joint dislocations need surgical treatment. This report described a new transacromial extra-articular Knowles pin fixation method to treat this very unstable dislocations to analyze this treatment. The hypothesis is that the results would be improved.

Thirteen consecutive patients with type V AC joint dislocations within 9 days of injuries were treated by open reduction transacromial extra-articular Knowles fixation, AC ligament repair, coracoclavicular (CC) ligament repair, CC augmentation sutures. All of them received postoperative arm sling supports for 3 weeks. The radiographic and clinical follow-up was at least 23 months. A modified Constant-Murley score was used for evaluation of bilateral shoulder functions.

All AC ligaments were torn at the clavicle sides. All CC ligament were torn at the mid-substances. The anterior deltoid insertions and the superior-posterior trapezius insertions to the clavicles were torn. Radio-lucent zones around the pins 1 mm to 3 mm were noted in all patients before pin removal. Lateral pin migration 1 mm to 2 mm were noted in nine patients before pin removal. Nine patients had increase of CC distances 1 mm to 4 mm at follow-up. Six patients had CC space calcifications. The mean modified Constant-Murley score of the injured shoulders was 94.5 +/- 2.7, the mean score of the uninjured shoulders was 93.9 +/- 1.3, which was not statistically different.

The transacromial extra-artocular Knowles pin fixation method is a reliable method to treat acute type V AC joint dislocations.