Subacromial Pain Syndrome. Treatment, diagnostic imaging and predictors of outcome

Abstract

Shoulder pain is very common, and subacromial pain syndrome is the most common diagnosis. Radial Extracorporeal Shock Wave Therapy (rESWT) is a treatment modality that is frequently used to treat this condition, despite limited evidence for its effectiveness. The purpose of this thesis was to compare improvement in pain and disability after radial Extracorporeal Shock Wave Therapy (rESWT) versus sham rESWT in patients who also received supervised exercises and to explore how calcification of the rotator cuff and treatment beliefs influence the outcome. In addition, to examine prognostic factors of 1-year outcome including structural changes detected on MRI. We conducted a randomized, controlled trial, recruiting patients with subacromial pain syndrome from our outpatient shoulder clinic at the Department of Physical Medicine and Rehabilitation, Oslo University Hospital. The patients were followed up at baseline, 12 and 24 weeks and 1 year. We found no significant difference regarding treatment effect between real rESWT and sham rESWT, except for the subgroup of patients with calcification in rotator cuff in the short term. Predictors of a poor outcome at 1-year were marital status as single, frequent use of pain medication, sick leave at baseline, negative outcome expectations, low self-reported general health status and few supervised exercise sessions. A moderate, but significant association between the change in SPADI from baseline to 1-year follow-up and the structural changes detected on MRI was found, with a poorer outcome for the patients with more structural changes. These findings indicate that rESWT treatment should be used only in shoulder patients with calcification in the rotator cuff. The observed prognostic factors may be addressed by the clinician in order to improve the clinical outcome.