Table 3:

Candidate Quantitative Composite Knee Scores in the Development Cohort

Score	Calculation
Principal Component 1**	Sum of CDI in the lateral and medial patella and BML in the medial patella
Principal Component 2*	Sum of BML in lateral and medial tibia
Principal Component 3*	Sum of CDI in the lateral patella, effusion-synovitis volume, and BML in the lateral patella
Principal Component 4*	Sum of CDI in the medial femur and tibia and BML in the medial femur
Principal Component 5*	Sum of BML in lateral femur, medial femur, and lateral patella
Principal Component 6*	Sum of CDI in the lateral femur and tibia
PCA-Weighted Total	Sum of all 13 measurements, weighted by the principal component loading
Inverse variance weighting Total	Sum of all 13 measures, Inverse variance weighted
Unweighted Total**	Sum of all 13 measurements (simple addition)
Cumulative Cartilage Damage**	Sum of all 6 CDI measures
BML+Effusion-Synovitis**	Sum of all 6 BML and effusion-synovitis measures
Whole knee BML volume	Sum of all 6 BML measures
Whole knee Effusion-Synovitis Volume	Sum of all effusion-synovitis volumes

^*All knee composite scores based on the principal components analysis are multiplied by the eigenvector for the component and divided by the sum of the eigenvectors of the 6 components.

^**Met criteria for further testing in the validation cohort.

PCA = principal component analysis, BML = bone marrow lesion, CDI = cartilage damage index