In a study from the Veterans Health Service Medical Center in Seoul, Republic of Korea, 2 MRI findings – joint capsule edema and thickness at the axillary recess – proved useful in predicting a stiff shoulder in patients with rotator cuff tears.
The researchers evaluated obliteration of the subcoracoid fat triangle, fatty degeneration of the torn rotator cuff muscle, and degree of retraction in 106 patients with small to large (5 cm or more) full-thickness rotator cuff tears plus joint capsule edema and thickness in the axillary recess. Tear size and location were determined by MRI findings and operative reports, while associations between MRI findings and preoperative passive range of motion (ROM) were determined by simple and multiple linear regression analyses and proportional odds logistic regression analysis.
Figure 1. A: Oblique coronal fat-suppressed T2-weighted MR image shows normal hypointense joint capsule at axillary recess (arrow). Note full-thickness tear of supraspinatus tendon (arrowheads) B: Oblique sagittal proton density MR image shows preserved subcoracoid fat triangle (asterisk). Images courtesy of the American Journal of Roentgenology (AJR).
In their paper, published online by the American Journal of Roentgenology (AJR), the authors wrote that, “There was a significant, negative linear correlation between limited ROM at forward elevation and thickness of the joint capsule in the glenoid portion of the axillary recess (p=0.018), external rotation and joint capsule edema in the humeral portion of the axillary recess (p=0.011), and internal rotation and joint capsule edema in the glenoid portion of the axillary recess (p=0.007).”
Fatty degeneration (p=0.003) was an independent predictor of limited ROM on internal rotation. Male sex (p = 0.041) and posterosuperior rotator cuff tear (p=0.030) were independent predictors of shoulder ROM on external rotation.
“This study is important,” the researchers noted, “because it is the first to highlight joint capsule abnormality on MRI as a factor associated with stiff shoulder in patients with full-thickness rotator cuff tears.”
Kim YY, Chung BM, Kim WT, Lee Y. MRI findings predictive of shoulder stiffness in patients with full-thickness rotator cuff tears. AJR Am J Roentgenol. 2020 Feb 18:1-6. doi: 10.2214/AJR.19.21973. [Epub ahead of print]