Table 4 Comparison and post hoc power analysis of patients with clavicular fracture (step A) versus anterior shoulder instability (step B).

From: Sectional measurements of shoulder muscle volume and computed tomography density in anterior shoulder instability

 

P-value

Cohen’s d value

Estimated size

Volume of Ssc

Y section

< 0.001

1.10

21

Y + 2.5 cm section

< 0.001

2.04

7

Y + 5 cm section

< 0.001

2.14

7

Volume of Isp + TM

Y section

< 0.001

1.20

18

Y + 2.5 cm section

< 0.001

1.29

11

Y + 5 cm section

< 0.001

1.56

11

CT density of Ssc

Y section

< 0.001

2.01

7

Y + 2.5 cm section

< 0.001

1.57

11

Y + 5 cm section

< 0.001

1.48

12

CT density of Isp + TM

Y section

< 0.001

1.57

8

Y + 2.5 cm section

< 0.001

1.93

8

Y + 5 cm section

< 0.001

2.11

7

VR Ssc/Isp+TM*

Y section

0.401

0.08

3973

Y + 2.5 cm section

0.047

0.53

86

Y + 5 cm section

0.076

0.45

118

CT-DR Ssc/Isp+TM*

Y section

0.067

−0.49

18

Y + 2.5 cm section

< 0.001

−1.22

18

Y + 5 cm section

< 0.001

−1.63

10

  1. Student t-test was used to compare the Step A and B results. Furthermore, to determine the study’s ability to detect a significant effect, a power analysis for the comparison was performed, and Cohen’s d value and estimated sample size were obtained. Sectional measurement of each shoulder muscle were performed as follows: from the most lateral end of the muscles to the plane of Y-view (Y section), to the plane 2.5 cm medial to the Y-view (Y + 2.5 cm section), and to the plane 5 cm medial to the Y-view (Y + 5 cm section).
  2. CT-DR CT density ratio, Isp infraspinatus, Ssc subscapular, TM teres minor, VR volume ratio.
  3. *VR Ssc/Isp+TM = ratio of muscle volume between the subscapularis and infraspinatus or teres minor; CT-DR Ssc/Isp+TM = ratio of CT density between the subscapularis and infraspinatus or teres minor.
Back to article page