Coracoid morphology and humeral version as risk factors for subscapularis tears

• Published in: Journal of shoulder and elbow surgery 2020-09, Vol.29 (9), p.1804-1810
• Main Authors: Leite, Maria J., Pinho, André R., Sá, Márcia C., Silva, Miguel R., Sousa, António N., Torres, João M.
• Format: Article
• Language: English
• Subjects: coracoid angle; coracoid length; coracoid morphology; Coracoid Process - diagnostic imaging; Coracoid Process - pathology; Female; Humans; humeral version; Humerus - diagnostic imaging; Humerus - pathology; Lacerations - epidemiology; Magnetic Resonance Imaging - methods; Male; Prognosis; Retrospective Studies; Risk Factors; Rotator Cuff - diagnostic imaging; Rotator Cuff Injuries - epidemiology; rotator cuff tears; Shoulder Joint - injuries; Single-Blind Method; subcoracoid impingement; Subscapularis; Tendinopathy - epidemiology
• ISSN: 1058-2746; 1532-6500
• DOI: 10.1016/j.jse.2020.01.074

The pathophysiology of subscapularis (SS) lesions is still relatively unknown despite recent interest in predictive factors for SS tears. Our goal was to determine the influence of the coracoid morphology and humeral version on SS tears. This was a retrospective, controlled, single-blinded study. We analyzed 232 shoulders with SS lesions confirmed by magnetic resonance imaging. The coracoid proximal length, coracoid distal length (CLD), and coracoid total length were measured. The coracoid length ratio, coracoid angle (CA), and humeral version were also evaluated. We found that greater humeral retroversion was progressively related to more serious SS injuries, with values of –28.6° ± 19.5° and –51.0° ± 11.1° in the normal SS group and tear group, respectively (P < .001). The same tendency was shown for the CA, with values of 123.8° ± 11.1° in the control group vs. 97.4° ± 10.1° in the tear group (P < .001). Greater CLD, coracoid total length, and coracoid length ratio were also associated with an increased risk of SS tears (P < .001). The CA and CLD represented the best predictors of SS tears, presenting areas under the receiver operating characteristic curve of 90.0% and 89.0%, respectively. This article is the first to study the influence of different parameters of the coracoid process morphology and humeral version on SS tears. We proved that humeral version and coracoid morphology were important risk factors for SS pathology and could accurately predict these lesions. Finally, our study was the first to create a classification system to divide coracoids according to their morphology and relative risk of associated SS tears.