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, 33 (1), 60-65

Evaluation of the Cross-Sectional Area of Acromion Process for Shoulder Impingement Syndrome


Evaluation of the Cross-Sectional Area of Acromion Process for Shoulder Impingement Syndrome

Young Joo et al. Korean J Pain.


Background: Anatomic changes in the acromion have been considered a main cause of shoulder impingement syndrome (SIS). To evaluate the relationship between SIS and the acromion process, we devised a new morphological parameter called the acromion process cross-sectional area (APA). We hypothesized that the APA could be an important morphologic diagnostic parameter in SIS.

Methods: We collected APA data from 95 patients with SIS and 126 control subjects who underwent shoulder magnetic resonance imaging (MRI). Then we measured the maximal cross-sectional area of the bone margin of the acromion process on MRI scans.

Results: The mean of APAs were 136.50 ± 21.75 mm2 in the male control group and 202.91 ± 31.78 mm2 in the male SIS group; SIS patients had significantly greater APAs (P < 0.001). The average of APAs were 105.38 ± 19.07 mm2 in the female control group and 147.62 ± 22.90 mm2 in the female SIS group, and the SIS patients had significantly greater APAs (P < 0.001). The optimal APA cut-off in the male group was 165.14 mm2 with 90.2% sensitivity, 91.4% specificity, and an area under the curve (AUC) of 0.968. In the female group, the optimal cut-off was 122.50 mm2 with 85.2% sensitivity, 84.9% specificity, and an AUC of 0.928.

Conclusions: The newly devised APA is a sensitive parameter for assessing SIS; greater APA is associated with a higher possibility of SIS. We think that this result will be helpful for the diagnosis of SIS.

Keywords: Acromion; Anatomy; Cross-Sectional; Diagnosis; Osteophyte; Parameter; Process; Shoulder; Shoulder Impingement Syndrome.

Conflict of interest statement


No potential conflict of interest relevant to this article was reported.


Fig. 1
Fig. 1
Oblique coronal proton density fast spin-echo magnetic resonance imaging in acromion sections: (A) normal control male; (B) shoulder impingement syndrome.

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