Assessment of acromial morphology in association with rotator cuff tear using magnetic resonance imaging

PurposeTo identify the morphological characteristics of the acromion associated with RCT using MRI. Also, to recognize which type of the acromion could be risk factor for full thickness RCT.Materials and methodsFifty-six patients with RCT (either partial or full thickness tear) and 30 control volunteers were enrolled in this study. Their shoulders were imaged by MRI. The acromial shapes were classified into type I (flat), type II (curved), type III (hooked) and type IV (convex). Additional measurements including acromial thickness, acromio-humeral distance (AHD), acromial index (AI) and lateral acromial angle (LAA) were performed for further assessment.ResultsType-II was the most commonly encountered acromial shape in both patients with RCT (44.6%) and control group (43.3%) with no significant difference in the incidence of each acromial shape between the two groups (P > 0.05). The acromial thickness, AHD, AI and LAA were significantly different in patients with RCT compared to control group (P < 0.001). Full thickness tear was significantly associated with type-III (P < 0.05).ConclusionType-III acromion (hooked shaped) could be a risk factor for full thickness RCT.