MRI findings predict shoulder stiffness for rotator cuff tears

Studying 106 patients with small to large (< 5 cm) full-thickness rotator cuff tears, in addition to joint capsule edema and thickness in the axillary recess, Yoon Yi Kim of Korea's Veterans Health Service Medical Center assessed obliteration of the subcoracoid fat triangle, fatty degeneration of the torn rotator cuff muscle, and degree of retraction.

Tear size and location were determined by MRI findings and operative report, while associations between MRI findings and preoperative passive range of motion (ROM) were evaluated with simple and multiple linear regression analyses and proportional odds logistic regression analysis.

As Kim and colleagues wrote: "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. Meanwhile, 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," Kim et al. 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."