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Table 4 Sensitivity of the 2D measurements to the mal-positioning of the ankle

From: Effects of positioning on radiographic measurements of ankle morphology: a computerized tomography-based simulation study

   X-axis   Y-axis   Z-axis
   -6 deg -3 deg Trend 3 deg 6 deg   -6 deg -3 deg Trend 3 deg 6 deg   -6 deg -3 deg Trend 3 deg 6 deg
Sagittal Plane Tibia Part               
  TiAL (mm) 0.0 0.0 - - 0.0 0.1   1.2 0.6 0.3 0.8   0.0 0.0 - - 0.0 0.0
  SRTi (mm) -0.6 -0.2 -0.1 -0.4   1.4 -0.2 0.0 1.9   0.0 0.0 - - 0.0 0.0
  APG (mm) 1.4 0.1 0.3 0.8   0.5 0.5 -0.2 -1.4   0.0 0.0 - - 0.0 0.0
  APA (deg) 1.3 0.1 0.2 0.8   -0.1 0.7 - -0.1 -1.6   0.0 0.0 - - 0.0 0.0
  MTiTh (mm) -0.1 -0.1 - - 0.1 0.2   -1.0 -0.5 0.4 1.1   -0.7 -0.1 -0.1 -0.4
  MDA (mm) 1.1 0.2 -0.5 -1.3   -0.5 0.4 - -0.2 -2.5   -19.3 -2.0 34.9 56.3
  MDV (mm) -0.8 -0.6 0.5 1.2   -0.7 -0.5 -0.1 -1.6   21.3 1.5 -5.9 -17.2
  Talus Part               
  TaAL (mm) 1.8 0.8 -0.8 -1.3   1.3 0.7 -1.1 -2.8   0.0 0.0 - - -0.1 -0.1
  TaR (mm) 1.0 0.6 -0.5 -0.5   3.5 1.7 -1.8 -2.7   0.1 0.0 - - -0.1 -0.2
Frontal Plane Tibia Part               
  TiW (mm) 0.0 0.0 - - 0.0 0.0   -0.2 -0.3 - 0.8 1.8   -0.2 -0.1 - - 0.1 0.2
  MalW (mm) 1.1 0.3 0.5 1.0   1.8 1.0 -1.0 -2.2   0.0 -0.1 - 2.5 2.2
  MLATi (deg) 35.3 18.7 -17.9 -36.1   -2.4 -1.3 1.6 3.6   -0.1 0.0 - - -0.3 -0.2
  Talus Part               
  TaW (mm) -18.4 1.1 2.5 -31.2   1.1 0.7 -1.0 -2.2   1.9 1.2 -0.6 -3.0
  MLATa (deg) 35.6 2.1 -11.6 160.1   0.1 -0.7 1.2 2.3   87.0 15.8 31.3 145.3
  1. Sensitivity of the parameters measured from 2D images subject to deviations in rotational components from the standard pose about each of the anatomical axes, as percentages of the values of the parameters measured in the standard pose. Positive and negative values indicated that the deviation caused an over-estimation and an under-estimation of the percentage values of the standard pose, respectively (X-axis: A/P; Y-axis: S/I; Z-axis: M/L). A dashed line indicates no significant trend. An upward (downward) arrow indicates a linearly increasing (decreasing) trend. An upward (downward) curved arrow indicates a quadratically increasing (decreasing) trend.