Reliability, validity, and minimal detectable change of the Step Test in patients with total knee arthroplasty

Background Step Test (ST) is frequently used to assess dynamic balance and locomotor function in clinical practice. Aims This study aimed to determine the concurrent validity, reliability, and minimal detectable change (MDC) of the ST in patients with total knee arthroplasty (TKA). Methods The study included 56 patients with TKA. The intraclass correlation coefficient (ICC) was used to assess the test-retest reliability of the ST. The correlations of the ST with timed up and go (TUG) and 10-m walk test (10MWT) were assessed for concurrent validity. Results Test-retest (ICC 0.90) reliability of the ST was determined to be excellent. The SEM and MDC95 values of test-retest reliability were 0.76 and 2.11, respectively. A significantly moderate correlation was found between the ST and TUG (p < 0.05, r: - 0.69), and 10MWT (p < 0.05, r: - 0.67). Conclusion The ST is a valid and reliable method in the assessment of dynamic balance ability and locomotor function in patients with TKA. The ST can be used to quantify changes in dynamic balance level and locomotor function in patients with TKA.