Coracoid Impingement and Morphology Is Associated with Fatty Infiltration and Rotator Cuff Tears

Abstract

This study describes measurements between the coracoid, glenoid, and humerus; characterizes coracoid shape, rotator cuff fatty infiltration, and quantitatively evaluates coracoid impingement and its association with anterosuperior rotator cuff tears (ASCT). 193 shoulder magnetic resonance imaging (MRI) scans demonstrating: rotator cuff tear; isolated tear of the supraspinatus; tear of supraspinatus and subscapularis, were included. MRI measurements included coracohumeral interval (CHI), coracoid overlap (CO), coracoid recess (CR), coracoglenoid angle (CGA), and coracoglenoid interval (CGI) on axial slices; acromiohumeral interval (AHI) on coronal slices; and coracohumeral interval (CHI) and coracoacromial ligament (CAL) thickness on sagittal slices. The coracoid shape was classified as flat, curved, or hooked. An Independent T-test was used to compare the MRI measurements and the different rotator cuff tear groups. In 79% of the patients with ASCT tears, the coracoid was curved. Axial CHI, CGA, sagittal CHI, and AHI were decreased in ASCT when compared to no tears and isolated supraspinatus tears (p < 0.05). CO was increased in ASCT compared to no tears and isolated supraspinatus tears (p < 0.05). Patients with an ASCT had a significantly increased subscapularis and supraspinatus Goutallier fatty infiltration score when compared to no tear and isolated supraspinatus tears (p < 0.05). These quantitative measurements may be useful in identifying patients at risk for ASCT. Level of Evidence III.