Subscapularis, medial, and lateral head coracohumeral ligament insertion anatomy

PURPOSE: The purpose of this study was to document the incidence of lesions of the rotator interval, illustrate the arthroscopic appearance of subtle differences in these lesions, and discuss how various lesions may affect biceps tendon stability in the bicipital groove. TYPE OF STUDY: A Data Registry has been used in my office since 1995 (Microsoft Office Access). This study reports on the results of a retrospective database "query" of the prospectively entered data from 1995 to 1998. Thus, by default, the format of this study is a consecutive sample. Only patients with a disruption of rotator cuff tendons, labrum and/or gleno-coracohumeral ligaments are included by study design. METHODS: This study has identified and reports on 46 arthroscopically identified subscapularis tears, 25 "hidden" rotator interval lesions (SGHL/MCHL complex) and 6 SGHL/CHL complex plastic deformation lesions in 165 patients undergoing shoulder arthroscopy for conditions ranging from anterior instability to rotator cuff tears. Arthroscopically identified lesions include partial or complete disruptions of the subscapularis tendon, disruptions of the superior glenohumeral/medial head coracohumeral ligament complex (SGHL/MCHL), disruptions of the lateral head coracohumeral ligament (LCHL), and various combinations of the above. RESULTS: The incidence rate of subscapularis tendon involvement in 165 arthroscopically treated shoulder patients was 27%. The incidence rate of subscapularis tendon disruptions with rotator cuff pathology was 35%. The incidence rate of SGHL/MCHL lesions (tear or stretch) in 165 arthroscopically treated shoulder patients was 18%. The incidence rate of SGHL/MCHL tears in 165 arthroscopically treated shoulder patients was 15%. Forty-seven percent of all subscapularis tears involved the SGHL/CHL complex. Ten percent of all rotator cuff tears involving the supraspinatus tendon involved the LCHL. CONCLUSIONS: This study has recorded the incidence of lesions of the subscapularis, SGHL/MCHL complex and/or the LCHL, and combinations thereof in degenerative cuff and instability patients. Primary lesions of the rotator interval can occur and regardless of the associated pathology, and if these lesions are not repaired, biceps tendon subluxation may exist.