Relationship between STV and pain scores
| Effect of change in STV on outcome (mm3) | ||||
|---|---|---|---|---|
| Model outcome | b* (95% CI) | p Value | β | Change in R2 overall† |
| KOOS pain subscale score (0–100), mean (SD) | −1.13 (−1.87 to −0.39) | 0.003 | −0.28 | 0.02 |
| Pain on nominated activity VAS (0–10), mean (SD) | 0.17 (0.05 to 0.29) | 0.006 | 0.32 | 0.04 |
Linear regression analysis.
*b coefficients have been scaled to reflect a change in STV of 1000 mm3. The models used to derive these coefficients were yit=Xit1β+Xit2β+αi+uit, where yit =either KOOS pain subscale score or VASNA, and Xit1=STV, Xit2=study visit (coded as dummy variables), αi=subject, and uit=error. Coefficients for study visit dummy variables not presented, for clarity.
†‘Change in R2 overall’=Difference in overall R2 between a fixed-effect panel model including study visit alone as the predictor and a fixed-effect panel model with study visit and STV as predictors—shows the amount of additional variance explained by adding STV into the fixed-effect regression models.
b, unstandardised coefficient; KOOS, Knee Injury and Osteoarthritis Outcome Score; STV, synovial tissue volume; VAS, Visual Analogue Scale; β, standardised coefficient.