Validation and reliability of six-minute walk test predictive model equation of total knee replacement

Background Total knee replacement (TKR) is the most common surgical technique for improving mobility, reducing pain, and improving quality of life in patients with end-stage osteoarthritis. The 6-minute walk test (6MWT) is a reliable assessment for evaluating changes in the physical performance among TKR patients. The goal of the current study was to compare predicted 6MWT distance and the actual 6MWT distance among patients who underwent TKR. Objective The objectives are to assess the predictive model equation’s validity in individuals who had undergone total knee replacements and to determine whether 6MWT’s predictive equation is reliable. Method Using purposive sampling, 82 samples of people who underwent TKR after 3 months were included. Knee range of motion, knee muscle strength, Knee Injury and Osteoarthritis Score (KOOS) pain score, and 6-minute walk test were used in the prediction equation. The patients’ (actual) 6MWT distance was measured and compared with the predicted values. The validity (concurrent validity) and reliability (test–retest reliability) of the 6MWD predictor model equation were evaluated. Result The correlation coefficient (Pearson r) between the actual six-minute walk test and the predictor equation value was 0.85, indicating high concurrent validity and also high test–retest reliability with intraclass correlation coefficient of 0.9. Conclusion The predicted 6MWT model evaluated in this study is proved to be valid and reliable which can be used to determine the walking distance a TKR patient should achieve at 3 months post-surgery.