Inferior position of the coracoid process increases the probability of risk factors for rotator cuff tear

A rotator cuff tear (RCT) refers to a partial or complete rupture of the rotator cuff (the tendons of the supraspinatus, infraspinatus, teres minor, and subscapularis muscles). It is commonly caused by degenerative changes or trauma and manifests as shoulder pain, weakness, and limited range of motion.This study aimed to explore the correlation between inferior position of coracoid process and risk factors for rotator cuff injury. (1) Does the inferior position of the coracoid process increase the probability of risk factors leading to RCT? (2) Does a lower positioning of the coracoid process increase the probability of subcoracoid impact? (3) Does a lower positioning of the coracoid process correlate with the shape of the acromion? From May 2018 to Dec 2019, 93 patients (38 males and 55 females) with rotator cuff injuries were analyzed, with an average age of 57.7 ± 6.2 years. All patients received X-ray examination with Anterior-posterior view and supraspinatus outlet view to distinguish acromion morphology before surgery. MRI scan was used to assess the rotator cuff injury. Three-dimensional computerized tomography examination measured the position of coracoid process. The location of rotator cuff injury and the subcoracoacromial arch impingement were evaluated by arthroscopy. Pearson chi-square test was used for statistical analysis of the position of coracoid process. 76.3% (71/93) of the patients had rotator cuff tear (RCT) within 1.5 cm of the biceps tendon groove lateral, and the rates were higher in Type III/IV coracoids. Total 60 cases had subacromial impact, while 28 cases had subcoracoid impacts. Type III/IV coracoids had a higher probability of impact. The prevalence of Type III/IV coracoid processes was 22 (78.6%) in the 28 cases with type III acromion, which was significantly higher than that in cases with Type I/II acromion (P = 0.034). The inferior position of the coracoid process increases the probability of RCT, which may be related to the high incidence of type III acromion in such patients and the reduction of the subcoracoid gap. Level III, therapeutic study.