Why does minimally invasive coracoclavicular ligament reconstruction using a flip button repair technique fail? An analysis of risk factors and complications.

Purpose: Aim of the present study was to evaluate the risk factors for the failure of coracoclavicular ligament reconstruction using a flip button repair technique and to analyse complications related to this procedure.

Methods: Seventy-one patients (3 female, 68 male) underwent surgical treatment using a flip button repair technique for an acute acromioclavicular joint dislocation. The following factors and its impact on clinical and radiographic outcome were assessed: age at trauma, interval between trauma and surgery, degree of displacement (according to Rockwood's classification), coracoid button position, button migration and post-operative appearance of ossifications.

Results: Sixty-three patients were available for follow-up. The overall Constant score was 95.2 points (range 61-100 points) compared to 97 points (range 73-100 points) for the contralateral side (p = 0.05). Nine patients (14.3 %) needed surgical revision. Inappropriate positioning of the coracoid bone tunnel with subsequent button dislocation was the most frequently observed mode of failure (6 cases, 9.5 %). Button migration into the clavicle was associated with loss of reduction (p = 0.02). The patient's age at the time of trauma had a significant impact on the clinical outcome, whereas younger patients achieved better results (p = 0.02). The interval between trauma and surgery did not significantly affect the outcome (n.s.).

Conclusion: Good to excellent clinical results can be achieved with the presented surgical technique. The age of the patient at trauma had a significant influence on the functional outcome. Furthermore, placement of the coracoid button centrally under the coracoid base is crucial to prevent failure.

Level Of Evidence: IV.