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Table 1 Sample size calculation for the required number of subjects in each treatment group (double sided).

From: A multi-centre randomized controlled trial comparing electrothermal arthroscopic capsulorrhaphy versus open inferior capsular shift for patients with shoulder instability: Protocol implementation and interim performance: Lessons learned from conducting a multi-centre RCT [ISRCTN68224911; NCT00251160]

Alpha level("p" value)

Power

 

60%

70%

80%

90%

0.10

12

15

20

27

0.05

16

20

25*

33

0.01

25

30

37

47

0.001

40

46

54

65

  1. N per group = 25* Expected dropout 12% 25/.88 = 28.4 Total per group 29 Grand Total 58 patients
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Trials

ISSN: 1745-6215