The Novel Acromial Angle is associated with the severity of full-thickness rotator cuff tear: a retrospective radiographic study

The study investigated the relationship between the Novel Acromial Angle (NAA) and the severity of rotator cuff tears. The research included 386 patients who underwent radiography and shoulder MRI between September 2023 and April 2025. Patients were divided into three groups: a control group without MRI findings, a partial tear group, and a full-thickness tear group. Results showed that the mean NAA was significantly smaller in both tear groups compared to the control group. A smaller NAA was significantly associated with larger full-thickness tear size. The diagnostic accuracy of NAA for identifying full-thickness tears was 0.76, which was higher than for partial tears (0.67). NAA was not associated with the depth of partial tears. The study concluded that NAA is a useful radiographic parameter for preoperative planning and assessing the need for acromioplasty, particularly in patients with full-thickness tears.