Ultrasound-Assessed Rotator Interval Vascularity Is Associated With the Immediate Response to Corticosteroid...

Adhesive capsulitis is characterized by progressive pain and restricted shoulder mobility, with inflammatory changes frequently observed in the rotator interval (RI). This study aimed to evaluate whether ultrasound-assessed RI vascularity is associated with immediate changes in shoulder external rotation range of motion following combined corticosteroid injection and radial extracorporeal shock-wave therapy (r-ESWT) in adhesive capsulitis.

In this single-group quasi-experimental preliminary study, 20 patients with adhesive capsulitis received intra-articular corticosteroid injection followed by five r-ESWT sessions targeting the RI. RI vascularity was assessed using power Doppler ultrasonography (PD-US) and graded using a four-point scale (Grades 0-3). Passive external rotation (ER) was measured before and after each session, and the immediate ER change (ΔER) was calculated. A linear mixed-effects model was employed to identify factors associated with ΔER while accounting for repeated measures.

Vascularity grade was significantly associated with ΔER (F = 11.42, p < 0.001). Compared with Grade 3, significantly smaller gains were observed in Grades 0 (estimate = -8.72, p = 0.014) and 1 (estimate = -8.91, p = 0.003), whereas Grade 2 exhibited a smaller improvement that did not reach statistical significance (estimate = -6.23, p = 0.051). No significant associations were observed for other examined covariates.

Greater RI vascularity assessed using PD-US was associated with larger immediate ΔER following combined corticosteroid injection and r-ESWT in patients with adhesive capsulitis. These exploratory findings suggest that PD-US-based vascular assessment may provide clinically relevant information regarding stage-related biological activity and short-term physiological responsiveness and warrant further investigation in larger controlled studies.