Of the 142 participants randomized to undergo biomechanics testing, complete data on biomechanics were obtained at baseline from 134 subjects (94%). A total of 116 of the 142 participants (82%) had complete data from at least 1 biomechanics followup visit (at 6 and/or 18 months). Of the 116 participants who completed at least 1 followup visit, 94 completed the 6-month followup, 84 completed the 18-month followup, and 62 completed both visits. There were no significant visit effects (6 or 18 months) for any of the outcome measures; therefore, the average intervention effects over the followup period were estimated and used in all subsequent analyses. The proportion of subjects who completed followup biomechanics testing (116 of 142; 82%) was similar to the completion rate for the primary outcome in the entire ADAPT cohort (252 of 316; 80%).