The role of magnetic resonance imaging in the assessment of acromial morphology in association with rotator cuff tear

Abstract

Background The pathogenesis of rotator cuff tear (RCT) remains controversial. The acromion portion of the scapula and its morphology may be attributable for a variety of shoulder disorders such as RCT. Aim The purpose of this article is to throw light on the role of MRI in the assessment of morphological characteristics of different acromial shapes in association with RCTs. Patients and methods This study was carried out from January to August 2016 at the Ahmed Maher Teaching Hospital Radiodiagnosis Department. We used MRI prospectively to image the shoulders of patients who presented to the radiology department with suspected RCT. Their ages ranged between 20 and 60 years with a mean age 40 years. Data were tabulated and manipulated using SPSS (vi 16), and the level of significance was less than 0.05. Results The study revealed that type III acromion was encountered in male and female patients (42.9 and 42.1%) and type IV acromion was noticed less frequently among male and female patients, respectively (4.8 and 15.8%). In patients younger than 45 years of age (n=25), type I and type III acromion was the most commonly seen (64%) in both sexes. In patients more than 45 years of age, type III acromion was commonly seen (60%). All age and sex differences were not significant (P>0.2). It also revealed that type III was mostly encountered in full-thickness tear (82.4%) and partial tear (52.9%), whereas type I was less frequently associated with partial tear or full-thickness tear (25%). Type III was associated with tendinopathy, acromioclavicular osteoarthritis, and joint effusion. Conclusion The acromial shapes were classified into four types. On MRI, acromial shapes were better recognized using the mathematical classification scheme for MRI obtained just lateral to the acromioclavicular joint. This should shed light on the morphological characteristics of different acromial shapes that may be of value in diagnosing and treating subacromial pathologies. Such morphological characteristics include measurements of the acromiohumeral distance, the acromial index, and the lateral acromial angle using T2-weighted MRI coronal oblique images.