Objective—To compare a sensor-based accelerometer-gyroscopic (A-G) system with a video-based
motion analysis system (VMAS) technique for detection
and quantification of lameness in horses.
Animals—8 adult horses.
Procedure—2 horses were evaluated once, 2 had
navicular disease and were evaluated before and after
nerve blocks, and 4 had 2 levels of shoe-induced
lameness, alternatively, in each of 4 limbs. Horses
were instrumented with an accelerometer transducer
on the head and pelvis, a gyroscopic transducer on
the right forelimb and hind feet, and a receiver-transmitter.
Signals from the A-G system were collected
simultaneously with those from the VMAS for collection
of head, pelvis, and right feet positions with horses
trotting on a treadmill. Lameness was detected
with an algorithm that quantified lameness as asymmetry
of head and pelvic movements. Comparisons
between the A-G and VMAS systems were made by
use of correlation and agreement (κ value) analyses.
Results—Correlation between the A-G and VMAS
systems for quantification of lameness was linear and
high ( r2 = 0.9544 and 0.8235 for forelimb and hind
limb, respectively). Quantification of hind limb lameness
with the A-G system was higher than measured
via VMAS. Agreement between the 2 methods for
detection of lameness was excellent (κ = 0.76) for the
forelimb and good (κ = 0.56) for the hind limb.
Conclusions and Clinical Relevance—The A-G system
detected and quantified forelimb and hind limb
lameness in horses trotting on the treadmill. Because
the data are collected wirelessly, this system might
be used to objectively evaluate lameness in the field.
( Am J Vet Res 2004;65:665–670)
Objective—To determine whether a shoe with an axialcontoured
lateral branch would induce greater lateral roll
of the forelimb hoof during the time between heel and
toe lift-off at end of the stance phase (breakover).
Animals—10 adult horses.
Procedure—A gyroscopic transducer was placed on
the hoof of the right forelimb and connected to a
transmitter. Data on hoof angular velocity were collected
as each horse walked and trotted on a treadmill
before (treatment 1, no trim–no shoe) and after 2
treatments by a farrier (treatment 2, trim–standard
shoe; and treatment 3, trim–contoured shoe). Data
were converted to hoof angles by mathematical integration.
Breakover duration was divided into 4 segments,
and hoof angles in 3 planes (pitch, roll, and
yaw) were calculated at the end of each segment.
Multivariable ANOVA was performed to detect differences
among treatments and gaits.
Results—Trimming and shoeing with a shoe with contoured
lateral branches induced greater mean lateral roll
to the hoof of 3.2° and 2.5° during the first half of
breakover when trotting, compared with values for no
trim–no shoe and trim–standard shoe, respectively. This
effect dissipated during the second half of breakover.
When horses walked, lateral roll during breakover was
not significantly enhanced by use of this shoe.
Conclusions and Clinical Relevance—A shoe with
an axial-contoured lateral branch induced greater lateral
roll during breakover in trotting horses, but
change in orientation of the hoof was small and limited
to the first half of breakover. (Am J Vet Res
Objective—To determine repeatability of a wireless, inertial sensor–based lameness evaluation system in horses.
Procedures—Horses were from 2 to 29 years of age and of various breeds and lameness disposition. All horses were instrumented with a wireless, inertial sensor-based motion analysis system on the head (accelerometer), pelvis (midline croup region [accelerometer]), and right forelimb (gyroscope) before evaluation in 2 consecutive trials, approximately 5 minutes apart, as the horse was trotted in a straight line. Signal-processing algorithms generated overall trial asymmetry measures for vertical head and pelvic movement and stride-by-stride differences in head and pelvic maximum and minimum positions between right and left sides of each stride. Repeatability was determined, and trial difference was determined for groups of horses with various numbers of strides for which data were collected per trial.
Results—Inertial sensor–based measures of torso movement asymmetry were repeatable. Repeatability for measures of torso asymmetry for determination of hind limb lameness was slightly greater than that for forelimb lameness. Collecting large numbers of strides degraded stride-to-stride repeatability but did not degrade intertrial repeatability.
Conclusions and Clinical Relevance—The inertial sensor system used to measure asymmetry of head and pelvic movement as an aid in the detection and evaluation of lameness in horses trotting in a straight line was sufficiently repeatable to investigate for clinical use.
OBJECTIVE To investigate associations between inertial sensor and stationary force plate measurements of hind limb lameness in horses.
ANIMALS 21 adult horses with no lameness or with mild hind limb lameness.
PROCEDURES Horses were instrumented with inertial sensors and evaluated for lameness with a stationary force plate while trotting in a straight line. Inertial sensor–derived measurements of maximum and minimum pelvic height differences between right and left halves of the stride were compared with vertical and horizontal ground reaction forces (GRFs). Stepwise linear regression was performed to investigate the strength of association between inertial sensor measurements of hind limb lameness and amplitude, impulse, and time indices of important events in the vertical and horizontal GRF patterns.
RESULTS Difference in minimum pelvic position was moderately (Ra2 = 0.60) associated with the difference in peak vertical GRF but had little association with any horizontal GRF measurements. Difference in maximum pelvic position was strongly (Ra2 = 0.77) associated with a transfer of vertical to horizontal ground reaction impulse in the second half of the stance but was not associated with difference in peak vertical GRF.
CONCLUSIONS AND CLINICAL RELEVANCE Inertial sensor–derived measurements of asymmetric pelvic fall (difference in minimum pelvic position) indicated a decrease in vertical GRF, but similar measurements of asymmetric pelvis rise (difference in maximum pelvic position) indicated a transfer of vertical to horizontal force impulse in the second half of the stance. Evaluation of both pelvic rise and fall may be important when assessing hind limb lameness in horses.
Objective—To assess the analytic sensitivity of an inertial sensor system for detection of the more severely affected forelimb in horses with bilateral lameness.
Animals—18 adult horses with forelimb lameness.
Procedures—Horses were fitted with inertial sensors and evaluated for lameness with a stationary force plate as they were trotted in a straight line. Inertial sensor-derived measurements for vertical head movement asymmetry (HMA) and vector sum (VS) of maximum and minimum head height differences between right and left halves of the stride were used to predict differences in mean peak vertical force (PVF) as a percentage of body weight between the right and left forelimbs. Repeatability was compared by calculation of the intraclass correlation coefficient (ICC) for each variable. Correct classification percentages for the lamer forelimb were determined by use of a stationary force plate as the standard.
Results—SEs of the prediction of difference in PVF between the right and left forelimbs from HMA and VS were 6.1% and 5.2%, respectively. Head movement asymmetry (ICC, 0.72) was less repeatable than PVF (ICC, 0.86) and VS (ICC, 0.84). Associations were positive and significant between HMA (R2 = 0.73) and VS (R2 = 0.81) and the difference in PVF between the right and left forelimbs. Correct classification percentages for HMA and VS for detecting the lamer forelimb were 83.3% and 77.8%, respectively.
Conclusions and Clinical Relevance—Results suggested that an inertial sensor system to measure vertical asymmetry (HMA and VS) due to forelimb lameness in horses trotting in a straight line has adequate analytic sensitivity for clinical use. Additional studies are required to assess specificity of the system.
Objective—To compare data obtained with an inertial sensor system with results of subjective lameness examinations performed by 3 experienced equine veterinarians for evaluation of lameness in horses.
Procedures—Horses were evaluated for lameness with a body-mounted inertial sensor system during trotting in a straight line and via subjective evaluation by 3 experienced equine practitioners who performed complete lameness examinations including lunging in a circle and limb flexion tests. Agreement among evaluators regarding results of subjective evaluations and correlations and agreements between various inertial sensor measures and results of subjective lameness evaluations were determined via calculation of Fleiss’ κ statistic, regression analysis, and calculation of 95% prediction intervals.
Results—Evaluators agreed on classification of horses into 3 mutually exclusive lameness categories (right limb lameness severity greater than left limb lameness severity, left limb lameness severity greater than right limb lameness severity, or equal right and left limb lameness severity) for 58.8% (κ = 0.37) and 54.7% (κ = 0.31) of horses for forelimb and hind limb lameness, respectively. All inertial sensor measures for forelimb and hind limb lameness were positively and significantly correlated with results of subjective evaluations. Agreement between inertial sensors measures and results of subjective evaluations was fair to moderate for forelimb lameness and slight to fair for hind limb lameness.
Conclusions and Clinical Relevance—Results of lameness evaluation of horses with an inertial sensor system and via subjective lameness examinations were significantly correlated but did not have strong agreement. Inertial sensor-based evaluation may augment but not replace subjective lameness examination of horses.
OBJECTIVE To evaluate head, pelvic, and limb movement to detect lameness in galloping horses.
ANIMALS 12 Thoroughbreds.
PROCEDURES Movement data were collected with inertial sensors mounted on the head, pelvis, and limbs of horses trotting and galloping in a straight line before and after induction of forelimb and hind limb lameness by use of sole pressure. Successful induction of lameness was determined by measurement of asymmetric vertical head and pelvic movement during trotting. Differences in gallop strides before and after induction of lameness were evaluated with paired-sample statistical analysis and neural network training and testing. Variables included maximum, minimum, range, and time indices of vertical head and pelvic acceleration, head rotation in the sagittal plane, pelvic rotation in the frontal plane, limb contact intervals, stride durations, and limb lead preference. Difference between median standardized gallop strides for each limb lead before and after induction of lameness was calculated as the sum of squared differences at each time index and assessed with a 2-way ANOVA.
RESULTS Head and pelvic acceleration and rotation, limb timing, stride duration measurements, and limb lead preference during galloping were not significantly different before and after induction of lameness in the forelimb or hind limb. Differences between limb leads before induction of lameness were similar to or greater than differences within limb leads before and after lameness induction.
CONCLUSIONS AND CLINICAL RELEVANCE Galloping horses maintained asymmetry of head, pelvic, and limb motion between limb leads that was unrelated to lameness.