Table A2:

Summary of Missing and Imputed Data by Timepoint. Intermittent missing data imputed using multiple imputation (MI) based on multivariate normal distribution. Data were not imputed after dropout/lost-to-follow-up or TKR. The number of each data type for WOMAC pain (observed WOMAC pain score; imputed using MI; missing due to drop-out/lost-to-follow-up, not imputed; missing due to TKR, not imputed) are shown for each year.

Year	Observed	Imputed	Missing: Dropout/Lost-to-Follow-Up	Missing: TKR
0	1093 (100%)	0 (0%)	0 (0%)	0 (0%)
1	1054 (96.4%)	39 (3.6%)	0 (0%)	0 (0%)
2	1038 (95%)	55 (5%)	0 (0%)	0 (0%)
3	976 (89.3%)	53 (4.8%)	32 (2.9%)	32 (2.9%)
4	950 (86.9%)	28 (2.6%)	55 (5%)	60 (5.5%)
5	851 (77.9%)	52 (4.8%)	96 (8.8%)	94 (8.6%)
6	797 (72.9%)	63 (5.8%)	114 (10.4%)	119 (10.9%)
7	770 (70.4%)	53 (4.8%)	128 (11.7%)	142 (13%)
8	767 (70.2%)	5 (0.5%)	154 (14.1%)	167 (15.3%)
9	632 (57.8%)	0 (0%)	274 (25.1%)	187 (17.1%)
Total	8928 (81.7%)	348 (3.2%)	853 (7.8%)	801 (7.3%)