Clin Orthop Surg.  2017 Jun;9(2):218-222. 10.4055/cios.2017.9.2.218.

Acromion Index in Korean Population and Its Relationship with Rotator Cuff Tears

• Kum DH
• Kim JH
• Park KM
• Lee ES
• Park YB
• Yoo JC

• KMID: 2412292
• DOI: http://doi.org/10.4055/cios.2017.9.2.218

Abstract

BACKGROUND
Among the many causes of rotator cuff tears, scapular morphology is associated with the accelerating degenerative process of the rotator cuff. Acromion index (AI) was previously introduced and compared in two populations.
METHODS
We enrolled 100 Korean patients diagnosed with full-thickness rotator cuff tears by magnetic resonance imaging and intraoperative arthroscopic findings between January and December 2013. Another 100 Korean patients with an intact rotator cuff tendon identified on magnetic resonance imaging and other shoulder diseases, such as frozen shoulder and instability, were enrolled as controls. We retrospectively compared these 100 rotator cuff tear patients (mean age, 63 years) and 100 controls (mean age, 51 years) in this study. Two independent orthopedic surgeons assessed the AI on radiographs. We performed an interobserver reliability test of the AI assessment, and then compared the AI between two groups.
RESULTS
The measurement of the AI showed excellent reliability (intraclass correlation coefficient, 0.82). The mean AI in the rotator cuff tear group was 0.68 and it was significantly different between groups (p<0.001, 95% confidence interval). The AI was not related to tear size.
CONCLUSIONS
Our study showed that the AI was an effective predictive factor for rotator cuff tears in a Korean population.

Keyword

Shoulder; Acromion; Rotator cuff injury; Prognosis

MeSH Terms

*Acromion/anatomy & histology/diagnostic imaging
Adult
Aged
Aged, 80 and over
Asian Continental Ancestry Group/*statistics & numerical data
Female
Humans
Magnetic Resonance Imaging
Male
Middle Aged
Prognosis
ROC Curve
Republic of Korea/epidemiology
Retrospective Studies
*Rotator Cuff Injuries/diagnostic imaging/epidemiology

Figure

• 

  Fig. 1 Acrominon index (AI). (A) AI was defined as the ratio of the distance from the glenoid to the lateral margin of the acromion (GA) divided by the distance from the glenoid rim to the lateral aspect of the humeral head (GH). (B) Anteroposterior radiographic view of the right shoulder: calculation of AI was done according to the method described in Fig. 1A.

• 

  Fig. 2 Comparison of acromion index (AI) on true anteroposterior (AP) radiographs: the AI was higher in the shoulder with a rotator cuff tear (A) than in the shoulder with an intact rotator cuff (B).

• 

  Fig. 3 Receiver operating characteristic curve for the acromion index in blue line. The reference line is indicated in black line.

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