Measurement properties of the L Test with fast walking speed in patients after lower limb amputation in initial prosthetic training phase

Abstract

The L Test is a clinical mobility test used in patients after lower limb amputation. To assess dynamic balance, it should be performed with fast walking speed. Its measurement properties in the initial prosthetic training phase are not known yet. The objective of the study was to establish intra- and interrater reliability, concurrent and discriminant validity, minimal detectable change, effect size between the rehabilitation time points and ceiling effect of the L Test with fast walking speed in patients after lower limb amputation in initial prosthetic training phase. The study included 36 inpatients aged 19-86 years who were provided with a prosthesis for the first time. They were assessed repeatedly with the L Test, Ten-meter Walk Test and 6-min Walk Test. The intra- (ICC3, k = 0.94) and interrater reliability (ICC2, k = 0.96) of the L Test were excellent. Correlations with the walking tests were very good (r = 0.75-0.86). Regression analysis with respect to the level of lower limb amputation showed a linear relationship with other variables (R2 = 0.55). Influences of age, cause of lower limb amputation and walking aid were statistically significant. The L Test was responsive to change after two weeks of prosthetic training (Cohen's d = 1.21). No ceiling effect was identified. The L Test with fast walking speed is a feasible, reliable, valid, and responsive measure of basic mobility skills in patients after lower limb amputation in the initial prosthetic training phase.