Three-dimensional evaluation of acromion morphology in patients with rotator cuff tear and subacromial impingement syndrome

In this study, the relationship of acromial morphology with rotator cuff tear (RCT) and subacromial impingement syndrome (SIS) was evaluated. The main aim of the study was to evaluate the clinical significance of acromion types, as well as to analyze the relationship of our newly developed morphological parameters - Acromion Cross-Sectional Area (ACA), Acromial Coverage Ratio (ACR), Acromial Projection Index (API) and Coracoacromial Distance (CAD) - with RCT and SIS by comparing them with existing parameters in the literature. A total of 73 subjects (35 patients, 38 healthy controls) were retrospectively evaluated. Traditional measurements —Critical Shoulder Angle (KOA), Lateral Acromial Angle (LAA), Acromiohumeral Distance (AHD), Objective Acromial Angle (OAA), acromion type— and new parameters —ACA, LAA, API, CAD— were evaluated on radiographic and magnetic resonance imaging (MRI) data When the results were analyzed, CSA, OAA, ACA and API values were found to be significantly higher in the patient group compared to the healthy control group, while LAA and AHM values were found to be lower (p < 0.05). ACR was also higher in the patient group than in the control group, but it remained at the threshold of statistical significance (p = 0.056).There was no significant difference between the groups in terms of acromion type and CAD values (p > 0.05) These results suggest that new parameters such as ACA and API may be potential markers in the diagnosis of RCT and SIS. The borderline significance of ACR (p = 0.056) suggests that the clinical value of this parameter should be confirmed in studies with larger samples. Acromion typing was found to be less clinically important than expected. The findings of the study may contribute to elucidate the role of acromial morphology in pathogenesis and new approaches to surgical planning. Keywords: Shoulder, Rotator Cuff Tear, Subacromial İmpingement Syndrome, Acromion Type, Critical Shoulder Angle, Lateral Acromial Angle, Acromio-Humeral Distance, Acromion Cross-Sectional Area, Acromial Coverage Ratio, Acromial Projection İndex, Coraco-Acromial Distance