Semi‐automated programs were used to quantify tibiofemoral and patellar cartilage damage, BML volume, and whole‐knee effusion‐synovitis volume. The candidate composite scores were formed by summing changes from baseline to 24 months based on pre‐specified methods. We evaluated the candidate composite scores:
- Ability to differentiate groups with and without KOA progression (17 radiographic and patient‐reported definitions);
- Sensitivity to change (standardized response means);
- Relative performance relating to legacy outcome measures of KOA progression.
Three out of the thirteen developed composite scores qualified for testing in the validation cohort (ranked by the sensitivity to change):
1) Whole‐knee cumulative cartilage damage
2) Unweighted total knee score
3) BML+effusion‐synovitis volume
The changes in the cumulative cartilage damage were associated with radiographic progression. Changes in the unweighted total knee score (OR=1.97) and BML+effusion‐synovitis score (OR=1.92) associated with WOMAC knee pain progression. In conclusion, two composite scores emerged, reflecting discrete domains of KOA progression. First, cumulative damage measured by a whole‐knee cartilage damage score reflects the damage accrued over time. Second, dynamic disease activity, measured by a BML+effusion‐synovitis score, relates to changes in a patient’s state of disease and symptoms.