MR evaluation of synovial injury in shoulder trauma.

The purpose of this study was to determine magnetic resonance imaging (MRI) findings relevant to synovial injury of the shoulder in patients with and without acute shoulder trauma. Three hundred and nine consecutive shoulder MRI studies (185-male, 124-female, 50 ± 15 years old) were retrospectively evaluated for findings suggestive of synovial injury including rupture and/or diverticulum of the joint capsule, bursa, and biceps tendon sheath (BTS), ganglion/synovial cyst, geyser phenomenon, and sequel of previous shoulder dislocation (Hill-Sachs deformity). Patients with one or more of these findings were included in the MR-positive group, whereas the remaining subjects were used as MR negatives. Based on their medical records, patients were also divided into trauma and non-trauma groups, and statistical analysis was performed to evaluate the association between the aforementioned MRI findings and history of shoulder trauma. Fifty-six patients were included in the MR-positive group and 253 in the MR-negative group. In MR-positive group, the incidence of capsular rupture (CR) and subacromial/subdeltoid (SASD) bursal rupture was higher in trauma patients, whereas the incidence of BTS diverticulum and ganglion cyst was higher in subjects without trauma. Significant association was found between the history of acute trauma and CR, SASD bursal rupture, BTS rupture, and Hill-Sachs deformity. In shoulder MR examination, presence of CR and/or SASD bursal rupture is strongly suggestive of acute shoulder trauma. In addition, BTS rupture and Hill-Sachs deformity are more prevalent in patients with acute shoulder trauma. The presence of these features should alert MRI readers to assess for additional trauma-related internal derangements, if a respective history has not been provided.