Arthroscopic treatment of acute acromio-clavicular joint dislocation with double flip button: two- to fouryear follow-up

Introduction The ideal treatment for acromio-clavicular (AC) joint dislocation is controversial, both in terms of indications and surgical technique. The present study evaluates the clinical and radiological outcomes at a minimum follow-up of two years in a group of patients with acute AC dislocation, arthroscopically repaired with two flip buttons and braided polyethylene sutures. Material and methods We treated 16 patients affected by acute AC joint dislocation, types III-V according to Rockwood. The bony tunnels in the clavicle and coracoid will host the coraco-clavicular retention system, which consists of two flip buttons (inferior and superior) fixed at the coracoid base and at the superior aspect of the clavicle, respectively, with polyethylene sutures looped around the internal eyelets. The mean follow-up was 31 months (range 24–48 months). At final follow-up patients were assessed using Constant score. AC joint comparative X-ray evaluations were also obtained at rest and under stress. Results The mean Constant score at final follow-up was 96.8 points (range 82–100), with full recovery of shoulder range of motion in all patients. All patients returned to all daily activities at mean 3.2 months post-operatively (range 3–4 months). At final follow-up, 12 shoulders (75%) maintained a complete reduction and four shoulders (25%) showed a partial loss of reduction, with a mean coraco-clavicular distance of 150% (range 136–172%) compared to the uninjured shoulder. Nevertheless, the functional outcomes of all these four patients were excellent, with a mean Constant score of 99 (range 97–100) and complete range of motion. Concomitant lesions observed at arthroscopy included three (18.75%) type 2 SLAP lesions and one (6.25%) Bankart lesion. Discussion The clinical results of the presented arthroscopic technique at an average follow-up of two years were excellent in terms of mean Constant score. From a radiological point of view one-fourth of the patients presented with a partial loss of reduction. It was associated to the migration of the superior flip button into the clavicle secondary to the penetration of the superior cortex that never progressed beyond the upper third of the collarbone. Nevertheless, all of these patients reported excellent functional outcome and were satisfied with the procedure despite a slight prominence of the lateral profile of the clavicle. Conclusions The presented technique proved to be safe and minimally invasive, delivering good clinical and aesthetic results while allowing the treatment of associated gleno-humeral lesions. Data will be presented.