Clinical and radiographical results after double flip button stabilization of acute grade III and IV acromioclavicular joint separations.

INTRODUCTION: Persistent horizontal instability after acute acromioclavicular (AC) joint separation may provoke unsatisfactory results of conservative treatment. HYPOTHESIS: the arthroscopically assisted double flip button stabilization of acute horizontally unstable grade III and IV AC joint disruptions results in full functional restoration and stable radiological reposition. MATERIALS: 21 patients treated for an acute grade III or IV AC joint separation were enrolled. Clinical assessment at least 2-year postoperative included the constant score (CS) and the simple shoulder test. A panorama stress view, bilateral axial view and an AC view were obtained for radiographic evaluation.
RESULTS: 19 individuals (mean 37 years; 17 men) with 16 Rockwood type III and 3 type IV injuries were available for examination 24–51 months postoperatively. The mean CS was 90.2 points (SD 6.5) with no statistically significant difference between CS and age-adjusted normative values. The mean Simple Shoulder Test scored 11.5 points (range 8–12). Loss of reduction of more than 2 mm in the coronal plane stress views was present in 6 patients (32 %) with no associated loss of functional outcome. Two of four reported complications in four patients were treated surgically (one open revision with graft augmentation for coracoid implant break out, one arthroscopic capsular release for persistent glenohumeral stiffness).
CONCLUSION: Arthroscopically assisted double flip button stabilization for acute grade III and IV AC joint separation restores fully horizontal stability and age-expected shoulder function, resulting in high patient satisfaction, despite a loss of reduction observed radiographically in approximately one-third of patients. LEVEL OF EVIDENCE: IV.