Acromioclavicular joint separation treated with clavicular hook plate: a study of radiological and functional outcomes

Introduction ACJ separation is a common shoulder injury. A variety of surgical techniques for high-grade ACJ separations have been described. A commonly used technique represents open reduction and fixation by a hook plate. Goal of the present study was to evaluate radiographic and functional outcome in patients with high-grade ACJ separations following surgical treatment with a hook plate before and after surgery as well as after hook plate removal. Materials and methods Patients undergoing surgery with a hook plate due to traumatic ACJ separation between 2012 and 2014 were included and examined during a follow-up control. Demographic and clinical data as well as radiographs pre- and postoperatively were evaluated. Additionally, range of motion, DASH Score and Constant-Murley Score (CMS) were analysed in a follow-up examination. Wilcoxon signed-rank test and Spearman's rank correlation were used for statistical analysis. Results 99 patients (88 m/11 w, 44 y) were included in the present study. 69 (64 m/5 w, 49 y) could be examined during long-term follow-up (38 month). After hook plate removal, the CCD increased significantly (13.7 +/- 0.9 mm) compared to the hook plate in situ (9.9 +/- 0.8 mm,p = 0.000001). 68% of all patients achieved a full range of motion post-operatively. Main limitations of range of motion affected external rotation as well as ante-/retroversion. Mean DASH Score was 5.6 +/- 1 points and CMS 90.0 +/- 1.4 points. Conclusion In contrast to a significant higher CCD after hook plate removal, nearly all patients achieved good to excellent functional results for DASH and CMS. This indicates that loss of reduction does not necessarily lead to poor functional outcome after ACJ separation surgery.