The reliability and validity of the Figure of 8 Walk test in older people with knee replacement: does the setting have an impact?
Barker KL., Batting M., Schlüssel M., Newman M.
OBJECTIVE: To determine the reliability and validity of the Figure of 8 Walk test (F8W) for older people after knee replacement surgery in the home setting. DESIGN: Observational repeated measures. SETTING: A specialist orthopaedic hospital and participants homes. PARTICIPANTS: Seventy-four older adults aged over 55 years one year following knee replacement surgery participated in two assessments more than one week apart. MAIN OUTCOME MEASURE: The time to complete, steps, boundary limits and smoothness score from the Figure of 8 Walk test (F8W), the time to complete the Timed Up and Go (TUG) test and the time to complete the Timed Walk Test (TWT). RESULTS: Overall, on 95% of occasions, the difference between the measurements for intra-rater reliability were within 1.8second of the two test times. The difference between the measurements for inter-rater reliability were found to be narrower than for intra-rater reliability with scores within 1.2second overall on 95% of occasions. The time to perform the F8W was highly correlated to the Timed Up and Go (overall sample r=0.921) and the variability spread within narrow limits (-0.8 to 0.8 z-scores). This was also true for the Timed Walk Test (overall sample r=0.834) with a narrow limit of variability on almost all of the observations (-1.16 to 1.16 z-scores). CONCLUSIONS: The F8W test has good reliability and validity when used in either a clinical or home setting for patients around one year following knee replacement surgery.