Objective—To evaluate the association between subjective
lameness grades and kinetic gait parameters
and assess the variability in kinetic parameters in
horses with experimentally induced forelimb lameness.
Procedures—Forelimb lameness was induced in
each horse via injection of lipopolysaccharide into 1
metacarpophalangeal joint (40 experimental trials).
Subjective lameness grading and 13 kinetic gait parameters
(force plate analysis) were assessed before
(baseline) and at 12, 18, and 24 hours after
lipopolysaccharide injection. While horses were trotting,
kinetic gait analysis was performed for 8 valid
repetitions at each time point. Repeated-measures
analyses were performed with 8 repetitions for each
kinetic parameter as the outcome, and lameness
grades, time points after lipopolysaccharide injection,
and repetition order as explanatory variables.
Sensitivity and specificity of kinetic parameters for
classification of horses as sound or lame (in relation
to subjective lameness scores) were calculated.
Between- and within-horse variabilities of the 13
kinetic parameters were assessed by calculation of
coefficients of variation.
Results—Subjective lameness grades were significantly
associated with most of the kinetic parameters.
Vertical force peak and impulse had the lowest
between- and within-horse coefficients of variation
and the highest correlations with subjective lameness
grade. Vertical force peak had the highest sensitivity
and specificity for lameness classification. Vertical
force peak and impulse were significantly decreased
even in horses with mild or unobservable lameness.
Conclusions and Clinical Relevance—Among the
kinetic gait parameters, vertical force peak and
impulse had the best potential to reflect lameness
severity and identify subclinical forelimb gait abnormalities.
(Am J Vet Res 2005;66:1805–1815)