Table 5.
Cross-sectional intraobserver reproducibility of joint space width measurements at baseline
| View | Observer | JSW (mm; mean ± SD) | Mean difference (mm; mean ± SD) | Limits of agreements | ICC values (95% CI) | |
| Reading 1 | Reading 2 | |||||
| Pelvic view | 1 | 2.33 ± 0.81 | 2.34 ± 1.07 | -0.01 ± -0.24 | -0.49 to +0.47 | 0.96 (0.93–0.98), 0.99 |
| 2 | 2.67 ± 0.81 | 2.66 ± 1.02 | -0.02 ± 0.16 | -0.30 to +0.34 | (0.98–0.99) 0.98 (0.97–0.99) | |
| Mean (1 + 2) | 2.50 ± 0.91 | 2.50 ± 0.89 | 0.004 ± 0.14 | -0.28 to +0.28 | ||
| Hip AP | 1 | 2.41 ± 0.86 | 2.40 ± 0.86 | 0.01 ± 0.25 | -0.49 to +0.51 | 0.96 (0.93–0.98), 0.99 |
| 2 | 2.69 ± 1.05 | 2.68 ± 1.01 | 0.01 ± 0.15 | -0.29 to +0.31 | (0.98–0.99) 0.98 (0.97–0.99) | |
| Mean (1 + 2) | 2.55 ± 0.94 | 2.54 ± 0.92 | 0.01 ± 0.16 | -0.30 to +0.32 | ||
| Oblique | 1 | 2.37 ± 0.79 | 2.29 ± 0.78 | 0.08 ± 0.37 | -0.89 to +0.71 | 0.88 (0.80–0.93), 0.98 |
| 2 | 2.69 ± 0.78 | 2.70 ± 1.01 | -0.02 ± 0.21 | -0.41 to +0.51 | (0.96–0.99) 0.96 (0.94–0.98) | |
| Mean (1 + 2) | 2.53 ± 0.85 | 2.50 ± 0.87 | 0.03 ± 0.21 | -0.29 to +0.35 | ||
Shown is the cross-sectional intraobserver reproducibility of radiographic measurements of joint space width (JSW) performed on baseline radiographs. CI, confidence interval; ICC, intraclass coefficient of correlation; SD, standard deviation.