Ultrasonographic Validity of Clinical Shoulder Impingement Signs in Patients Without Limitation of Motion.

Objective: To analyze ultrasonographic findings associated with subacromial impingement syndrome and adhesive capsulitis in patients with unrestricted shoulder joint motion and positive impingement signs during physical examinations, and assess pain improvement after intraarticular steroid injections to verify the potential presence of early-stage adhesive capsulitis. Design: Prospective, noninterventional, observational study. Setting: Outpatient clinic of the Department of Physical Medicine and Rehabilitation at a single general hospital. Participants: Twenty-seven patients (N=27) presenting with unilateral shoulder pain and no limitation in joint motion. Interventions: Not applicable. Main Outcome Measures: At the initial visit, ultrasonography was performed to measure supraspinatus tendon thickness and evaluate for bicipital groove fluid collection and subacromial bursitis. All patients received sonography-guided intraarticular steroid injections. Pain and functional status were assessed using the Visual Analog Scale (VAS) and the Korean version of the Shoulder Pain and Disability Index (SPADI) at baseline and at a 2-week follow-up. Positive impingement signs were confirmed via the painful arc, Neer, Hawkins-Kennedy, Paxinos, and horizontal adduction tests. Results: There was no significant difference in supraspinatus tendon thickness between the painful and nonpainful shoulders. However, VAS scores showed a significant decrease at follow-up. Both SPADI total disability scores and total SPADI scores demonstrated statistically significant improvement. Conclusions: Patients with preserved shoulder range of motion but positive impingement signs, often diagnosed as subacromial impingement syndrome, may in fact represent early-stage adhesive capsulitis. Ultrasonography and steroid injection response may help differentiate these conditions in clinical practice.