Radiographic findings in patients suspected of subacromial impingement syndrome in relation to shoulder pain and disability.

Abstract

The aim was to study the association between specific radiographic findings and patient reported shoulder pain and disability in patients suspected of subacromial impingement syndrome (SIS). This cross-sectional study used baseline data from a prospective study. Study population included patients age 18 to 63 years, referred to orthopaedic clinic on suspicion of SIS. Radiographic findings before first visit to a department of orthopaedic surgery comprised subacromial calcifications, acromial morphological characteristics (i.e. acromial type and spur), acromioclavicular osteoarthritis, signs of previous glenohumeral dislocation (Bankart/Hill-Sachs lesions), and architectural measures (i.e. acromial tilt, acromion index, and lateral acromial angle). Shoulder pain and disability were evaluated using the Oxford Shoulder Score (OSS) from patient's response to a questionnaire at first visit to the public department of orthopaedic surgery or before surgery for SIS. A low OSS was defined as having a score < 25. Associations between the radiographic findings and low OSS were analysed using logistic regression. The population comprised 825 patients. Median time between radiographic examination and completion of the questionnaire was 9 days (SD = 27.1). In adjusted analysis, we found a statistically significant association for lateral spur especially birdbeak type (OR = 2.24 (95% CI 1.36-3.71)), Bankart/Hill-Sachs lesion (OR = 2.49 (95% CI 1.38-4.48)), and acromial tilt > 35° (OR = 0.62 (95% CI 0.41-0.94)). Female sex (OR = 2.25 (95% CI 1.59-3.18)) was also associated with low OSS. In terms of associations with patient-reported shoulder pain and disability, lateral spurs, with emphasis on birdbeak type, Bankart/Hill-Sachs lesions, and acromial tilt > 35°, seemed clinically important.