Correlation between Potential Risk Factors for Subacromial Impingement Syndrome and Subcoracoid Impingement - A Retrospective Radiological Study

BACKGROUND Shoulder discomfort ranks third among musculoskeletal complaints that might cause disability. The pathogenesis and associated risk factors of impingement remain poorly understood. This study seeks to identify a potential correlation between structural risk factors for developing SAIS and subcoracoid impingement. METHODS This radiological study collected data retrospectively for patients with clinical signs and symptoms of shoulder impingement. The MRI (Magnetic Resonance Imaging) included for initial screening were symptomatic patients with suspected impingement syndrome, living in Jeddah, Saudi Arabia. Six hundred eighty-six patients with MRI were included in the study that met the inclusion criteria. Pearson correlation coefficient was used to analyze the correlation between acromiohumeral and coracohumeral distance. RESULTS Out of 686 screened MRIs, a total of 391 had SAIS (Subacromial Impingement Syndrome), whereas subcoracoid impingement was found in 238 cases. There was a significant association in the presence of these two syndromes (P = 0.000, X2 = 35.209, df = 1). A total of 176 patients (72.7%) with subcoracoid impingement also had signs of SAIS, suggesting a very strong association. However, 66 patients (27.2%) with subcoracoid impingement did not exhibit radiological features of SAIS. CONCLUSIONS No correlation was found between the decrease in coracohumeral and acromiohumeral distance. The factors associated with isolated SAIS were female gender, downsloping of the acromion, complete supraspinatus tendon tear, and supraspinatus and subscapularis tendinopathy.