Predicting bursal-side supraspinatus tendon tears with the acromioclavicular angle
Issued Date
2025-01-01
Resource Type
eISSN
22146873
Scopus ID
2-s2.0-85210052824
Journal Title
Asia-Pacific Journal of Sports Medicine, Arthroscopy, Rehabilitation and Technology
Volume
39
Start Page
15
End Page
21
Rights Holder(s)
SCOPUS
Bibliographic Citation
Asia-Pacific Journal of Sports Medicine, Arthroscopy, Rehabilitation and Technology Vol.39 (2025) , 15-21
Suggested Citation
Saengpetch N., Bamrungchaowkasem J., Chitrapazt N., Kongmalai P. Predicting bursal-side supraspinatus tendon tears with the acromioclavicular angle. Asia-Pacific Journal of Sports Medicine, Arthroscopy, Rehabilitation and Technology Vol.39 (2025) , 15-21. 21. doi:10.1016/j.asmart.2024.11.003 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/102783
Title
Predicting bursal-side supraspinatus tendon tears with the acromioclavicular angle
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Corresponding Author(s)
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Abstract
Background: Bursal-side supraspinatus tendon tears are a common form of rotator cuff injury, often associated with acromial impingement and other extrinsic factors. Existing anatomical parameters, such as the lateral acromion angle, acromial index, and critical shoulder angle, have been studied in relation to rotator cuff tears; however, reliable indicators specific to the risk of bursal-side supraspinatus tears remain lacking. The acromioclavicular (AC) angle, which reflects the angular relationship between the acromion and clavicle, may offer a new predictive marker for this specific pathology. Methods: In this retrospective case-control study, patients presenting with shoulder pain between January 2016 and February 2020 were reviewed. Group 1 included patients with isolated bursal-side supraspinatus tendon tears confirmed by arthroscopy, while Group 2 consisted of age- and gender-matched controls without rotator cuff pathology. The AC angle was measured using both X-ray and MRI. Diagnostic performance was assessed through Receiver Operating Characteristic (ROC) curve analysis, identifying the optimal cut-point with Youden's index. Reliability was measured using the Intraclass Correlation Coefficient (ICC) for both intra- and inter-rater reliability. Results: The ROC analysis determined an optimal AC angle cut-point of ≤160°. X-ray measurements showed moderate diagnostic value (AUC 0.60, sensitivity 67.2 %, specificity 51.7 %), while MRI measurements demonstrated good diagnostic performance (AUC 0.79, sensitivity 84.5 %, specificity 70.7 %). X-ray yielded high sensitivity but low specificity, suggesting its utility as an initial screening tool, whereas MRI provided improved diagnostic accuracy. Reliability assessments indicated high intra- and inter-rater reliability for AC angle measurements across both imaging modalities (ICC >0.80). Conclusion: The AC angle, particularly when measured on MRI, may serve as a valuable diagnostic marker for identifying isolated bursal-side supraspinatus tendon tears. While X-ray can be utilized as an accessible screening tool, combining it with clinical assessments and MRI is recommended for greater diagnostic precision. Further multi-center, prospective studies are warranted to confirm the clinical utility of the AC angle in predicting rotator cuff pathology.