Acromial Index in Indian Population and it’s Significance on Rotator Cuff Tears

Abstract

Background: The etiopathogenesis of rotator cuff tears remains debatable. Among the many causes, abnormal scapular morphology has been found to accelerate the degenerative process of rotator cuff tears. The morphology and lateral extension of the acromion process were assessed indetail by Nyffeler et al. and the Acromion Index (AI) was introduced, which measures the lateral extension of the acromion. It was theorized that a large lateral extension of the acromion increased the chances of the supraspinatus tendon to degenerate because of impingement between the acromion and the deltoid muscle. The AI was compared between patients with rotator cuff tears and patients with an intact rotator cuff. Methods: 21 Indian patients presenting to the orthopaedics OPD, Yenepoya Medical College, with rotator cuff tears were taken up for this study between August 2020 and February 2021. Another 21 patients with intact rotator cuff and other shoulder diseases such as frozen shoulder were included in this study. Patients with rotator cuff tears were included in group A, and patients with intact rotator cuff were included in group B. Both groups had the AI measured on radiographs, and their values were compared. Results: The mean Acromial Index (AI) in the rotator cuff tear group was 0.74 and in the intact rotator cuff group it was 0.59, which was statistically significant. There was no statistical difference in AI between male and female patients. The mean age of the patients in the rotator cuff group was 50.8 years, and in non rotator cuff tear group, it was 50.2 years. Conclusion: Acromial Index is a useful predictive tool for detecting rotator cuff tears in the Indian population. Further studies are required to assess its usefulness in predicting the progression of a rotator cuff tear. Keywords: Rotator cuff tear; Acromial Index; Shoulder.