Table 2 The comparisons of the mean knee pain at three measurement time points
Measurement | Group | P value (t-test) | RM ANOVA | Mixed model analysis with interaction a,b | ||||
|---|---|---|---|---|---|---|---|---|
Intervention, Mean ± SD | Placebo, Mean ± SD |  | Parameter | P value | Parameter | Estimate | P value | |
Baseline pain | 6.86 ± 1.60 | 6.25 ± 1.61 | 0.111 | Time | 0.001 | Intercept | 5.527 | .000 |
Pain after 4 weeks | 5.22 ± 1.70 | 5.69 ± 1.52 | 0.221 | Group | 0.001 | Baseline pain | 0.733 | .000 |
Pain after 6 weeks | 4.52 ± 1.78 | 5.66 ± 1.65 | 0.006 | Group×time | 0.001 | Time | −0.494 | .080 |
Intervention group | −1.133 | .006 | ||||||
Baseline pain ×group | −.712 | .002 | ||||||
Baseline pain×time | −0.018 | .233 | ||||||