Aponeurotic expansion of the supraspinatus tendon and concomitant shoulder pathologies.

OBJECTIVES: We investigated the correlation of aponeurotic expansion of the supraspinatus tendon (AESST) with shoulder pathologies such as long head of biceps tendon (LHB), supraspinatus tendon (SST), and subscapularis tendon (SSc). METHODS: We retrospectively evaluated 47 healthy patients and 163 patients with shoulder symptoms from August 2014 to March 2021. First, the presence of AESST was evaluated based on Moser et al.'s classification. Second, the presence of abnormal findings of including LHB tendinitis, LHB subluxation, SST tendinitis, SST tear, SSc tendinitis, and SSc tendon tear was evaluated. We analyzed the prevalence and type of AESST between the two study groups and the relationship between abnormal findings and the presence of AESST. RESULTS: The prevalence of AESST for readers 1 and 2 was 26.1% and 30.4% in the asymptomatic group, respectively, and 22.8% and 31.3% in the symptomatic group. Type 1 was most common (17.3-23.9%) followed by types 2a and 2b. There were no significant differences in the distribution of aponeurosis type between the two groups. In the AESST-positive groups, 45.9% and 47.1% had SST tears on examination by readers 1 and 2, respectively, whereas only 26.4% and 27.9% had SST tears in the AESST-negative group suggesting AESST is associated with SST tear. The odds ratio for SST tear in the presence of AESST was 2.370 and 2.294 (readers 1 and 2). CONCLUSIONS: There is an association between SST tears and the presence of AESST. KEY POINTS: • We evaluated the prevalence of aponeurotic expansion of the supraspinatus tendon (AESST) on MR imaging by type in both symptomatic and asymptomatic groups. • We investigated the correlation of AESST with shoulder pathologies such as biceps tendon and supraspinatus tendon tears. • There is an association between SST tears and the presence of AESST. • Radiologists should be aware of the risk of rotator cuff pathology if AESST is detected.