Quantitative MRI indicators and features for partial subscapularis tendon tears on conventional shoulder MRI

BACKGROUND: Diagnosing partial subscapularis (SSC) tendon tears still faces challenges. A failure rate of massive posterosuperior rotator cuff tear repair will be highly increased when extending more than one-third of SSC tendon. This study aims to investigate the quantitative indicators and features of partial SSC tears on conventional shoulder MRI and improve the preoperative diagnostic accuracy. MATERIALS AND METHODS: Four hundred and thirty-seven patients underwent MRI and arthroscopy were retrospectively reviewed; 89 patients with partial SSC tears in case group and 50 patients with normal SSC in control group were included. Six MRI features with the explicit definition of some quantitative indicators were evaluated. RESULTS: Fissure sign showed the highest diagnostic efficiency for the partial SSC tears, with a specificity of 92%, sensitivity of 75.3%, and accuracy of 81.3%. Thinning of SSC, fluid collection under the coraco-glenoid arch (CGA), and combined SSP complete tear also showed high specificity of 86%, 80%, and 80%, respectively, while the sensitivity and accuracy were moderate, with a sensitivity of 38.2%, 50.6%, and 48.3%, respectively, an accuracy of 55.4%, 61.2%, and 59.7%, respectively. The specificity, sensitivity, and accuracy of lesser tuberosity cysts were all moderate with values of 68%, 56.2%, and 60%, respectively. However, fat accumulation under the CGA showed no significant difference between the partial SSC tears group and the control group. CONCLUSION: Several specific MRI features with quantitative indicators defined in this study can be used to improve the accuracy of preoperative MRI diagnosis of partial SSC tears.