Comparing the critical shoulder angle of patients with non-traumatic rotator cuff tears and those without rotator cuff tears

Background A tear of the rotator cuff is a common reason for shoulder pain. The rotator cuff not only contributes to dynamic stability and muscular balance of the shoulder joint but also plays a fundamental role in generating shoulder movement. A higher critical shoulder angle often increases the likelihood of a rotator cuff tear (RCT). The primary objective of the study is to compare the critical angle of the shoulder among patients with and without non-traumatic RCT reporting to a tertiary care centre, with a secondary objective to determine the association between age and critical shoulder angle in the non- traumatic RCT group. Methodology A cross-sectional comparative study was conducted in the Department of Orthopaedics at a Government Medical College, Kerala, India. A total of 30 patients, above 20 years of age with non-traumatic rotator cuff tears, were included in group A, while patients presenting with complaints other than non-traumatic RCT were included in group B. Data on demographics, comorbidities, clinical features and critical shoulder angle were collected and analyzed using SPSS software. Categorical data were analyzed using the chi-square test, and continuous variables using the t-test. Results The distribution of participants was comparable according to gender, but not in age. The critical angle was significantly higher in Group A compared to Group B ( p = 0.001). In addition, a significantly low positive correlation was observed among participants in Group B ( r = 0.391; p = 0.033) and a negligible correlation among participants in Group A ( r = 0.173; p = 0.36). Conclusion The non-traumatic RCT had a higher critical angle of the shoulder compared to patients with no RCT. An increase in age was correlated with an increase in critical angle of the shoulder among patients without a non-traumatic tear in the rotator cuff and overall participants, but not among participants with a non-traumatic RCT. Clinical trial number Not applicable.