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Abstract

Introduction: Studies implicating coracoid impingement as a causative process for subscapularis and long head of biceps tendon (LHB) lesions are inconclusive. No study has addressed the contribution of soft tissues, including the conjoined tendon and the coracoacromial ligament. The purpose of this study is to examine the relationship between subcoracoid bony and soft tissue encroachment and the development of pathologic lesions of the rotator cuff and LHB. Methods: Patients were randomly selected from those having arthroscopic surgery over the past three years. Fifty patients (36 males, 14 females; mean age 55.2) with arthroscopic evidence of subscapularis or LHB pathology were compared to fifty (31 males, 19 females; mean age 43.4) without such pathology. Average coracohumeral distance (CHD), coracoid overlap (CO), and coracoid index (CI) were measured on digital MRI both in the standard fashion, and using analogous measurements to the tip of the soft tissue overlying the coracoid process. Results: CHD was significantly narrowed in the pathology group for both bony (11.04 vs 12.94 mm; p<0.05) and soft tissue (7.71 vs 9.85 mm; p<0.001) measurements. Soft tissue CO was greater in the pathology group (17.14 vs 14.73 mm; p<0.05). CI was significantly increased in the pathology group for both bony (7.44 vs 3.71 mm; p<.001) and soft tissue (9.91 vs 5.73 mm; p<.0005) measurements. Discussion and Conclusion: There is a strong association between decreased coracohumeral distance, as well as greater protrusion of the coracoid past the glenoid, and lesions of the subscapularis and LHB. This association is even stronger when taking into account the soft tissue contribution to coracoid impingement. Key Words: Coracoid impingement, subscapularis, biceps tendon. If noted, the author indicates something of value received. The codes are identified as follows: a, research or institutional support; b, miscellaneous funding; c, royalties; d, stock options; e, consultant or employee. *The Food and Drug Administration has not cleared the drug and/or medical device for the use described in this presentation (ie, the drug or medical device is being discussed for an “off-label” use). If noted, the author indicates something of value received. The codes are identified as follows: a, research or institutional support; b, miscellaneous funding; c, royalties; d, stock options; e, consultant or employee. *The Food and Drug Administration has not cleared the drug and/or medical device for the use described in this presentation (ie, the drug or medical device is being discussed for an “off-label” use).