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

Objective: 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).

Materials and methods: 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.

Results: 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.

Conclusion: 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.