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Table 6 Longitudinal (M0–M36) intraobserver reproducibility and sensitivity to change of joint space width measurements

From: Reproducibility and sensitivity to change of various methods to measure joint space width in osteoarthritis of the hip: a double reading of three different radiographic views taken with a three-year interval

View Observer JSW change (mm; mean ± SD) Difference (mm; mean ± SD) 95% CI approximation of bias Limits of agreements ICC value (95% CI) SRM calculated on reading 1 (95% CI)
   Reading 1 Reading 2      
Pelvic 1 -0.40 ± 0.65 -0.49 ± 0.54 0.09 ± 0.36 -0.01 to +0.19 -0.63 to +0.81 0.81 (0.69–0.89) -0.61 (-0.65 to -0.57)
  2 -0.54 ± 0.66 -0.49 ± 0.67 -0.05 ± 0.16 -0.09 to -0.01 -0.37 to +0.27 0.97 (0.95–0.98) -0.82 (-0.84 to -0.80)
  Mean (1 + 2) -0.47 ± 0.62 -0.49 ± 0.57 0.02 ± 0.18 -0.2 to +0.06 -0.34 to +0.38 0.95 (0.92–0.97) -0.76 (-0.77 to -0.73)
Hip AP 1 -0.39 ± 0.61 -0.46 ± 0.59 0.07 ± 0.30 -0.01 to +0.15 -0.53 to +0.67 0.87 (0.78–0.92) -0.64 (-0.67 to -0.61)
  2 -0.49 ± 0.66 -0.49 ± 0.66 -0.00 ± 0.14 -0.04 to +0.04 -0.28 to +0.28 0.97 (0.96–0.99) -0.75 (-0.77 to -0.73)
  Mean (1 + 2) -0.44 ± 0.62 -0.48 ± 0.60 0.03 ± 0.16 -0.01 to +0.07 -0.29 to +0.35 0.96 (0.94–0.98) -0.72 (-0.74 to -0.70)
Oblique 1 -0.46 ± 0.59 -0.37 ± 0.50 -0.09 ± 0.40 -0.21 to +0.03 -0.89 to +0.71 0.73 (0.57–0.84) -0.77 (-0.80 to -0.74)
  2 -0.47 ± 0.67 -0.52 ± 0.64 0.05 ± 0.23 -0.10 to +0.11 -0.41 to +0.51 0.93 (0.88–0.96) -0.70 (-0.74 to -0.67)
  Mean (1 + 2) -0.46 ± 0.61 -0.45 ± 0.53 0.03 ± 0.16 -0.10 to +0.07 -0.29 to +0.35 0.91 (0.85–0.95) -0.76 (-0.79 to -0.73)
  1. Shown is the longitudinal intraobserver reproducibility and sensitivity to change (standardized response mean [SRM]) of radiographic measurements of joint space width (JSW; change from baseline [M0] to M36) on 3 different views read by two observers (and their mean). AP, anteroposterior; CI, confidence interval; ICC, intraclass coefficient of correlation; SD, standard deviation.