Number of test trials needed for performance stability and interrater reliability of the one leg stand test in patients with a major non-traumatic lower limb amputation

Abstract

Introduction: Balance is beneficial for daily functioning of patients with a lower limb amputation and sometimes assessed by the one-leg stand test (OLST). The aims of the study were to examine (1) the number of trials needed to achieve performance stability, (2) the interrater reliability of the OLST in patients with a major non-traumatic lower limb amputation, and (3) to provide a test procedure.

Methods: Thirteen women and 23 men with a mean age (SD) of 67.4 (10.6) years; 19 below-knee and 17 above-knee amputees who performed the OLST at a mean of 14.5 (4.5) days post-amputation. All patients performed five timed OLST-trials with 1-min rest intervals between trials, supervised by a physical therapist, of which 28 included in the reliability-part conducted this twice, separated with a mean of 3.4 (0.78)h. Repeated measures Friedman determined the number of trials needed to ensure stable OLST-scores while the ICC1.1, the standard error of measurement (SEM) and the smallest real difference (SRD) determined reproducibility.

Results: No learning curve was found for the five OLST-trials (p=0.241), with the best of the five trials reaching a median (25-75% quartile) of 2.9 (1.7-8.2)s, and with only six patients able to stand for more than 10s. The ICC (95% CI), SEM and SRD were respectively 0.87 (0.61-0.96), 0.99 s and 2.74 s.

Conclusion: Findings suggest that the best of five trials be used for the OLST in unilateral non-traumatic amputee patients as we found excellent interrater reliability and acceptable agreement when using this score.

Keywords: Amputation; Balance; Number of test trials, Reliability; One-leg-stand-test.