Magnetic resonance imaging: Clinical correlation in surgically treated isolated subacromial impingement syndrome

This study aimed to evaluate the relationship between magnetic resonance imaging (MRI) findings and clinical symptoms, including pain and shoulder function, in patients with isolated subacromial impingement syndrome (SAIS).

A retrospective cross-sectional study was conducted in 73 patients with surgically confirmed isolated SAIS between January 2024 and September 2025. Preoperative clinical evaluation included the Visual Analog Scale (VAS) for pain assessment, Constant scoring for functional evaluation, and the Neer and Hawkins impingement tests for physical examination. MRI evaluation encompassed quantitative parameters-acromiohumeral distance (AHD), critical shoulder angle (CSA), lateral acromial angle (LAA), subacromial volume (SAV), and osteophyte size when present-as well as qualitative assessments of acromial morphology (based on the Bigliani classification), acromial orientation, acromioclavicular joint osteoarthritis, acromial spur formation, supraspinatus tendinosis grading, and subacromial-subdeltoid bursitis.

No significant associations were identified between AHD, CSA, or SAV with either pain scores or functional performance (p > 0.05 for all comparisons). Supraspinatus tendinosis severity showed moderate correlations with both VAS (ρ + 0.517; p < 0.001) and Constant score (ρ + -0.497; p < 0.001). Multivariable linear regression analysis revealed that both tendinosis grade (B + -7.720; 95% CI: -10.843 to -4.596; p < 0.001) and LAA (B = 0.446; 95% CI: 0.109-0.784; p = 0.010) were independently associated with Constant Score.

In this surgically treated cohort, the degree of supraspinatus tendinosis is moderately correlated with clinical symptoms and functional impairment, and both tendinosis severity and LAA independently predict shoulder function. Other morphologic descriptors and quantitative MRI measurements do not reliably reflect clinical severity. These findings should be interpreted within the limitations of a selected surgical population and cross-sectional design.

Shoulder pain can affect daily activities, and MRI scans are often used to look for possible causes. This study compared MRI findings with pain and shoulder function in people with subacromial impingement syndrome. This study found that more severe tendon damage was linked to worse pain and lower shoulder function, while many other MRI features were not closely linked to symptoms. This matters because understanding which MRI findings are most closely related to symptoms may help clinicians better assess and manage shoulder problems.