Statistical analysis
pain
SECONDARY, COMPLICATIONS
Power and sample size considerations for the trial are found in Supplementary Material A repeated-measures analysis of change of VAS pain score (and change of KOOS pain score) was performed with a means model via the SAS MIXED Procedure (version 9.4; SAS Institute, Cary, NC), providing separate estimates of the means by treatment group (BMAC, SVF, UCT and CSI) time on study (1, 3, 6, 9 and 12 months on study) and treatment group. The models included treatment arm, time on study, the statistical interaction between treatment arm and time on study and study center as fixed effects. A compound-symmetric variance–covariance form in repeated measurements was assumed, and robust estimates of the standard errors of parameters were used to perform statistical tests and construct 95% confidence intervals (CIs)The heterogeneity of treatment effects across levels of a baseline variable was investigated using a statistical test for interaction. A prespecified subgroup analysis is one that is planned and documented before examination of the data. Planned subgroup analyses were performed to examine the impact of treatment on the primary outcomes in the prespecified subgroups (that is, sex, ethnicity and KL grade). Effect of treatment in subgroups was determined by including the interaction between treatment and subgroup in the repeated-measures model described above using an observed case analysis. Additional secondary and exploratory outcome measures included change in MRI cartilage and joint health from baseline to 1 year, analysis of AEs and complications between groups, as well as in-depth cellular analysis of each injectate.