ABSTRACT
Purpose: The Purpose of this study is to detect differences between the values of dynamic coracohumeral distance [CHD] measured using ultrasonography [USG] in different shoulder rotations and to investigate its correlation with subscapularis tear
Methods:We prospectively enrolled consecutive patients [n = 84] who were scheduled to have arthroscopic rotator cuff repair. Patients with a history of previous shoulder surgery or shoulder fracture and patients with external rotation less than 30 were excluded from the study. Dynamic coracohumeral distance was measured utilizing ultrasonography in 3 different shoulder positions: external rotation, neutral and internal rotation. We assessed the intrarater reliability with 3 times repetition of measurement. Patients were divided into one of 3 groups according to arthroscopic findings: intact subscapularis, partial-thickness tear, and full-thickness tear of the subscapularis. The control group [n = 12] included patients without rotator cuff tears from the outpatient clinic. Subgroup analysis according to the presence of dynamic subcoracoid stenosis, defined as a coracohumeral distance less than 6 mm measured in internal rotation was performed to find the clinical effect of dynamic subcoracoid stenosis
Results: A partial-thickness tear of the subscapularis tendon was present in 30 patients [35.7%] and a full-thickness tear in 13 patients [15.5%] among 84 patients. The CHD was maximum in external rotation and the narrowest in internal rotation. There were no statistical differences in the CHDs between groups with different subscapularis tear status. According to the presence of dynamic subcoracoid stenosis, patients with dynamic subcoracoid stenosis had a significantly higher incidence of partial-thickness subscapularis tear than those without stenosis [P = 0.018]
Conclusions: The coracohumeral distance values were narrowest in shoulder internal rotation, which is thought to be the pathogenic position. We could not confirm the correlation between coracohumeral distance and subscapularis tear. However, patients who have dynamic subcoracoid stenosis had significantly higher incidence of subscapularis tear than others without dynamic stenosis