Operative Fixation of Chronic Acromioclavicular Joint Dislocation With Hook Plate and Modified Ligament Transfer.

PURPOSE: The optimal treatment for acute dislocation of the acromioclavicular (AC) joint remains unclear, and prior randomized trials did not reveal any significant improvements in the operative groups. However, it is clear that some patients treated nonoperatively are dissatisfied with their outcome and request surgical correction. This video demonstrates one method of repair of a chronic dislocation of the AC joint in a patient with significant symptomatology following nonoperative treatment of a high-grade AC dislocation.
METHODS: This video demonstrates the open reduction of a chronically dislocated AC joint. After mobilization of the distal clavicle and debridement of the joint, a step cut is made in the anterior surface of the distal clavicle. The coracoacromial (CA) ligament is then identified and mobilized, taking care to preserve its acromial origin. An anterior acromioplasty is then performed with a microsaggital saw. The AC joint is reduced, and the acromial fragment is sculpted to fit the step cut in the distal clavicle, where it is then fixed with a small-fragment cancellous screw in lag fashion. The blade of the hook plate is then contoured to fit under the acromion (posteriorly) to hold the joint in a reduced position. The deltoid is repaired with number 1 absorbable sutures, followed by a standard closure.
RESULTS: Results are improved and complications minimized when care is taken to not avoid overreduction of the clavicle: an intraoperative radiograph, and/or comparison to the opposite side, may be useful. We do not shorten or resect the entire distal clavicle: this has been shown to lead to worse outcomes. We have found that CA transfer with a fragment of attached acromial bone results in more reliable healing than a CA transfer alone (the Weaver-Dunn transfer). DISCUSSION: In the setting of a chronic AC dislocation, hook plate fixation provides excellent reduction of the joint and a stable mechanical environment: this allows for the optimal healing of the ligament transfer. Typically, 6-12 months postoperatively, the hook plate can be removed to improve motion and reduce local irritation because joint stability is then provided by the transfer with bone-to-bone healing.