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Table 4 Power analysis, and numbers needed for non-inferiority study

From: Trochanteric osteotomy versus posterolateral approach: function the first year post surgery. A pilot study

 

Power current study

Numbers needed per approach (total) *

HHS

21.1%

398

(796)

WOMAC pain

15.2%

469

(930)

WOMAC stiffness

33.4%

278

(556)

WOMAC function

10.7%

1197

(2394)

  1. * numbers needed to perform a non-inferiority study, with α = 0.05 and power of 0.8 (1 - β), based on the results of the current study