Scapular dyskinesis and SICK scapula syndrome following surgical treatment of type III acute acromioclavicular dislocations

Purpose: To evaluate the incidence of scapular dyskinesis and SICK scapula syndrome (defined as scapular malposition, infero-medial border prominence, coracoid pain and malposition, and dyskinesis of scapular movement) in patients treated surgically for acute type III AC dislocation. Methods: Development of scapular dyskinesis and SICK scapula syndrome following conservative treatment has been described in the literature. In the present study, we evaluated 34 patients treated with different surgical techniques for acute type III AC dislocations. Functional outcome, radiographic evaluation of clavicular reduction and scapular kinematics were all evaluated. Results: Scapular dyskinesis was observed in only 4 (11. 7 %) patients, of which only 1 (2. 9 % of the sample) was affected by SICK scapula syndrome. Scapular dyskinesis was classified as type I in 3 cases (75 %) and type III in 1 case (25 %). Constant shoulder scores (mean 95. 7 points, SD ± 5. 3) and Simple Shoulder Test results (mean 11. 2 points, SD ± 0. 8) were excellent. Recurrence of separation was observed in 4 patients. Conclusions: Surgical treatment of type III acute AC joint dislocations is associated with a lower incidence of scapular dyskinesis and SICK scapula syndrome, if compared to data reported in the literature on conservative treatment. Level of evidence: Retrospective study, Level IV.