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Published on: February 10, 2015
Acromion types and morphometric evaluation of subacromial impingement syndrome in the Chinese population
Yuanxun Lin1, Jundan Wei2, Lixin Tang1
1School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China.
Background:
The acromion can have different shapes and sizes among different populations. Measuring the morphological structures of the shoulder joint can facilitate a better understanding of the causes of SIS issues. The study explores the correlation between acromion types and the morphological measurements of acromion in SIS among the Chinese population.
Materials And Methods:
A retrospective study. Between January 2024 and September 2024, MRI of 128 cases that were diagnosed as SIS and met the criteria were included in the study. Measurements taken from the MRI images included types of acromion, acromion humeral distance (AHD), acromion index (AI), acromion-greater tubercle impingement index (ATI), critical shoulder angle (CSA), lateral acromion angle (LAA), and slope of the acromion.
Results:
Type I acromion was observed in 29 cases (22.66%), type II acromion in 79 cases (61.72%), and type III acromion in 20 cases (15.62%). AHD, AI, ATI, CSA, LAA, and slope of acromion among the various acromion types. (AHD: p < 0.001; AI: p = 0.002; ATI: p = 0.009; CSA: p < 0.001; LAA: p < 0.001; slope of acromion: p < 0.001) According to type I and type II acromions characteristic curve analysis, the cut-off values for AI, ATI, CSA, LAA, and slope of acromion were 0.76, 0.96, 53.37°, 77.82° and 10.12°. According to type II and type III acromions characteristic curve analysis, the cut-off values for AHD and slope of acromion were 8.51 mm and 15.77°.
Conclusions:
In summary, AHD, AI, ATI, CSA, LAA, and the slope of the acromion show significant differences among the three types of acromion in subacromial impingement syndrome. The slope of the acromion serves as a reliable MRI measurement parameter for distinguishing between type I and type II acromions, as well as type II and type III acromions in SIS patients. These measurement parameters are of great importance for diagnosing and treating subacromial impingement syndrome.
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