gms | German Medical Science

Objectives: Diagnosis of subscapularis tendon (SSC) lesions on magnetic resonance imaging (MRI) can be challenging. A small coracohumeral distance (CHD) has been associated with SSC tears. This study was designed to define a specific threshold value for CHD to predict SSC tears on axial MRI scans.

Methods: This retrospective study included 172 shoulders of 168 patients that underwent arthroscopic surgery for rotator cuff tear (RCT) or glenohumeral instability (GI). Diagnostic arthroscopy confirmed an SSC tear in 62 cases (36.0%, test-group a), RCT tears other than SSC in 71 cases (41.3%, control-group b) and GI without any RCT in 39 cases (22.7%, zero-sample-group c). All patients had a preoperative MRI of the shoulder (1.5T or 3T). Minimum CHD was measured on axial fat suppressed PD, T2 or T1-weigthed sequences. Receiver Operating Characteristics (ROC)- analysis was used to determine the threshold value for CHD and sensitivity and specificity were calculated.

Results and Conclusion: CHD measurement had a good interobserver reliability (ICC 0.799). Mean CHD was highly significantly (p<0.001) less for test-group a (mean 7.3mm, standard deviation (SD) ±2.2) compared to control-group b (mean 11.1mm, SD ±2.3) or zero-samplegroup c (mean 13.6mm, SD ±2.9). A threshold value of CHD <9.5mm had a sensitivity of 83.6% and a specificity of 84.5% to predict SSC tears.

Conclusion: A CHD <9.5mm on MRI is predictive of SSC lesions and a valuable tool to diagnose SSC tears.