Reliability of the six-minute walk test after total hip arthroplasty

Background: Walking ability is a crucial component of lower extremity function. Assessment of walking after total hip arthroplasty (THA) provides important information about the healing process. Walking endurance, an important functional component of walking, can be reliably measured with the 6-minute walk test (6 mWT). Even though the 6 mWT is commonly used in patients with THA, its reliability has never been reported for this patient population. The aim of this study is to assess the reliability of the test-retest 6 mWT after THA. Methods: Thirty-four patients with THA performed two test trials on the same day, separated by a one hour seated rest. To assess reliability, intra-class correlation coefficient (ICC2,1), standard error of measurement (SEM), and smallest real difference (SRD) were calculated. Results: The 6 mWT showed a high reliability. The patients walked 3.71 metres more at the end of the second 6 mWT in comparison with the first test. The ICC2,1 (AS(95)), SEM (m), SEM95 (m) and SRD95 (m) were 0.96 (0.92), 3.67, 7.19, and 10.17 m respectively. Conclusions: Reliability of the 6 mWT was high in patients with THA. The 6 mWT is a simple and sensitive method to measure the functional performance in patients with THA in the clinical setting. Moreover, clinicians and researchers can use the 6 mWT to quantify even small changes in functional performance after THA.