RESUMO
Background: The thickening of the inferior glenohumeral joint capsule (IGC) is a characteristic finding in frozen shoulders. However, the relationship between the thickness of the IGC measured using ultrasonography (US) and the range of motion (ROM) remains unclear. This study aimed to investigate a suitable IGC thickness measurement site that can reflect the ROM of frozen shoulders. Methods: The participants were 29 patients with frozen shoulder and 20 healthy shoulders of 10 healthy adult. US measurements of the IGC were performed at 80° elevation in the scapular plane, with thickness was measured at 3 levels in both groups: just above the surgical neck, just above the anatomical neck, and at the parenchymal level. The relationship between thickness and ROM at the 3 levels was also assessed. The thickness of the IGC was evaluated using magnetic resonance imaging and US, as well as the validity of US evaluation. Results: There was a positive correlation (r = 0.72) between magnetic resonance imaging-measured and US-measured IGC thickness. The IGC was thicker in the frozen shoulder group than in the control group at all 3 levels (P < .001). The thickness of the IGC at the parenchymal level showed a significant negative correlation with all ROMs: flexion (r = -0.63), abduction (r = -0.60), external rotation (r = -0.50), and internal rotation (r = -0.52). Conclusion: The thickness of the IGC at the parenchymal level is negatively correlated with the ROM. The evaluation of the IGC in this study will be helpful in selecting treatment options for frozen shoulders.
RESUMO
BACKGROUND: Ulnar collateral ligament (UCL) and flexor-pronator muscle (FPM) injuries are common in baseball players. However, the sites of FPM injuries and the relationship between UCL and FPM injuries in baseball players have not been fully clarified. The purpose of this study was to identify the sites of FPM injuries and to determine the relationships of location and severity of UCL injury with the presence of FPM injuries in baseball players. METHODS: UCL and FPM injuries were diagnosed using magnetic resonance imaging in 99 baseball players. The sites of FPM injuries were identified on coronal, sagittal, and axial images. UCL injury severity was classified into four grades: chronic changes, low-grade partial tear, high-grade partial tear, and complete tear. UCL injury location was classified as proximal UCL tear or distal UCL tear. All images were assessed by a musculoskeletal radiologist and an orthopedic surgeon. RESULTS: Combined UCL and FPM injuries were observed in 45 of 99 players, of which 40 of 45 (89%) involved injury of the flexor digitorum superficialis (FDS). All FDS injuries were in the deep layer of the muscle belly. There was no significant difference between the severity of UCL injury and presence of FPM injuries (P = .352). There was a significant association of distal UCL tears with FPM injuries (P < .001). CONCLUSION: FDS injury occurs most commonly in the muscle belly of the second and fifth digits. There may be no relationship between the severity of UCL injury and presence of FPM injury in baseball players. FPM injuries may be a contributing factor in the failure of nonoperative management of distal UCL tears in baseball players.