The relationship between rotator cuff tear and four acromion types: cross-sectional study based on shoulder magnetic resonance imaging in 227 patients.

BACKGROUND: Rotator cuff tear (RCT) has been believed to be related to specific types of the acromion. However, most of the studies were performed on a small number of patients with surgical findings not considering the severity of RCT.

PURPOSE: To analyze the relationship between age, gender, the side of the shoulder, the acromion type, and the severity of RCT using shoulder magnetic resonance arthrography (MRA).

MATERIAL AND METHODS: A total of 277 shoulder MRA findings were analyzed by a radiologist specializing in the musculoskeletal system. The relationship between variables (age, gender, side of the shoulder, and acromion type) and the injury of the supraspinatus (no rupture, partial rupture, full rupture, complete rupture) was confirmed. The partial tear of the supraspinatus tendon was divided into bursal and articular side tear in order to investigate the damage caused by the anatomical difference of the acromion. We also confirmed the differences between single supraspinatus injury and multiple RCTs.

RESULTS: The severity of supraspinatus tear and multiple RCTs were statistically significant with the old age and the right side of the shoulder, but not with a specific acromion type. In supraspinatus partial tear, there was no statistical difference between bursal and articular side tears.

CONCLUSION: Our study revealed that the age at which degeneration could occur also was associated with multiple RCTs and is considered to be the most important factor in RCT, not anatomical structures such as acromion type.