Article

Three-dimensional motion analysis has provided important information
about functional outcome for patients who have undergone total knee replacement,
yet many comparisons to control populations are inconclusive. Some of these
findings may be explained by variability in patients' repeated performance,
however this has not been previously reported. Therefore the objective of this
study was to determine the variability of repeated performance in patients who
have undergone total knee replacement during walking and selected activities of
daily living using three-dimensional motion analysis. METHODS: The variability of
kinematic and kinetic parameters over six repetitions of walking at comfortable
and fast speeds, lunging, stair ascent and descent, squatting and standing up
from sitting were measured using motion analysis. Variability was calculated
using both the co-efficient of variation, and the group average of the range of
data within each subject. FINDINGS: During level walking the within-subject
difference was less than 3.2 degrees or 0.9 Nm/kg and co-efficients of variation
ranged from 2% to 29%. When patients performed other activities of daily living
the within-subject difference was up to 8.2 degrees or 1.3 Nm/kg and
co-efficients of variation were between 0.5% and 50.5%. INTERPRETATION: Although
patients walked and performed the activities with reasonable consistency, the
variability of their performance appeared to be related to the size of the group
mean for each parameter. Comparison of patient groups on parameters with small
mean values requires larger sample sizes to prevent intra-subject variability
from obscuring differences between groups.

Langue : ANGLAIS