Assessing Minimal Detectable Changes and Test-Retest Reliability of the Timed Up and Go Test and the 2-Minute Walk Test in Patients With Total Knee Arthroplasty.

Abstract

Two-minute walk test (2MWT) and the Timed Up and Go test (TUG) are simple, quick, and can be applied in a short time as part of the routine medical examination. They were shown to be reliable and valid tests in many patient groups. The aims of the present study were: (1) to determine test-retest reliability of data for the TUG and 2MWT and (2) to determine minimal detectable change (MDC) scores for the TUG and 2MWT in patients with TKA. Forty-eight patients with total knee arthroplasty, operated by the same surgeon, were included in this study. Patients performed trials for TUG and 2MWT twice on the same day. Between the first and second trials, patients waited for an hour on sitting position to prevent fatigue. The TUG and 2MWT showed an excellent test-retest reliability in this study. Intraclass correlation coefficient [ICC(2,1)] for TUG and 2MWT were 0.98 and 0.97, respectively. Standard error of measurement and MDC₉₅ for TUG were 0.82 and 2.27, respectively. Standard error of measurement and MDC₉₅ for 2MWT were 5.40 and 14.96, respectively. The TUG and 2MWT have an excellent test-retest reliability in patients with TKA. Clinicians and researchers can be confident that changes in TUG time above 2.27 seconds and changes in 2MWT distances above 14.96 meters, represent a "real" clinical change in an individual patient with TKA. We, therefore, recommend the use of these 2 tests as complementary outcome measures for functional evaluation in patients TKA.