Objective—To evaluate pelvic movement over a large
number of strides in sound horses and in horses with
induced hind limb lameness by applying methods to
the pelvis that have been described for evaluating vertical
head movement in horses with induced forelimb
Animals—17 adult horses.
Procedure—Horses were filmed while trotting on a
treadmill before and after induction of transient mild
and moderate hind limb lamenesses. Vertical pelvic
movement was measured by a signal decomposition
method. The vertical pelvic signal was decomposed
into a periodic component (A1) that occurred at half
the stride frequency (representing vertical pelvic
movement caused by lameness) and another periodic
component (A2) that occurred at stride frequency
(representing normal vertical pelvic movement of a
trotting horse). Vertical pelvic and foot positions were
correlated for each stride to compare the difference
between the minimum and maximum heights of the
pelvis during and after stance of the right hind limb to
the minimum and maximum heights of the pelvis during
and after stance of the left hind limb.
Results—Maximum pelvic height difference and
lameness amplitude (A1) differed significantly
between sound and mild or moderate hind limb lameness
conditions. Mean A1 value for vertical pelvic
movement in sound horses was less than that previously
reported for vertical head movement.
Conclusions and Clinical Relevance—Pelvic height
differences and signal decomposition of pelvic movement
can be used to objectively evaluate hind limb
lameness in horses over a large number of strides in
clinical and research settings. (Am J Vet Res 2004;65:
Objective—To investigate continuous wavelet transformation
and neural network classification of gait
data for detecting forelimb lameness in horses.
Animals—12 adult horses with mild forelimb lameness.
Procedure—Position of the head and right forelimb
foot, metacarpophalangeal (ie, fetlock), carpal, and
elbow joints was determined by use of kinematic
analysis before and after palmar digital nerve blocks.
We obtained 8 recordings from horses without lameness,
8 with right forelimb lameness, and 8 with left
forelimb lameness. Vertical and horizontal position of
the head and vertical position of the foot, fetlock,
carpal, and elbow joints were processed by continuous
wavelet transformation. Feature vectors were
created from the transformed signals and a neural
network trained with data from 6 horses, which was
then tested on the remaining 2 horses for each category
until each horse was used twice for training and
testing. Correct classification percentage (CCP) was
calculated for each combination of gait signals tested.
Results—Wavelet-transformed vertical position of
the head and right forelimb foot had greater CCP
(85%) than untransformed data (21%). Adding data
from the fetlock, carpal, or elbow joints did not
improve CCP over that for the head and foot alone.
Conclusions and Clinical Relevance—Wavelet
transformation of gait data extracts information that is
important for the detection and differentiation of forelimb
lameness of horses. All of the necessary information
to detect lameness and differentiate the side
of lameness can be obtained by observation of vertical
head movement in concert with movement of the
foot of 1 forelimb. (Am J Vet Res 2003;64:1376–1381)
Objective—To identify hind limb and pelvic kinematic
variables that change in trotting horses after induced
lameness of the distal intertarsal and tarsometatarsal
joints and after subsequent intra-articular administration
Animals—8 clinically normal adult horses.
Procedure—Kinematic measurements were made
before and after transient endotoxin-induced lameness
of the distal intertarsal and tarsometatarsal joints and
after intra-articular administration of anesthetic.
Fourteen displacement and joint angle (metatarsophalangeal
[fetlock] and tarsal joints) measurements were
made on the right hind limb, sacrum, and the right and
left tubera coxae. Kinematic measurements were compared
by general linear models, using a repeated measures
ANOVA. Post hoc multiple comparisons between
treatments were evaluated with a Fisher least squared
difference test at α = 0.05.
Results—After lameness induction, fetlock and tarsal
joint extension during stance decreased, fetlock joint
flexion and hoof height during swing increased, limb protraction
decreased, and vertical excursion of the tubera
coxae became more asymmetric. After intra-articular
administration of anesthetic, limb protraction returned to
the degree seen before lameness, and vertical excursion
of the tubera coxae became more symmetric.
Conclusions and Clinical Relevance—Increased
length of hind limb protraction and symmetry of tubera
coxae vertical excursion are sensitive indicators of
improvement in tarsal joint lameness. When evaluating
changes in tarsal joint lameness, evaluating the horse
from the side (to assess limb protraction) is as important
as evaluating from the rear (to assess pelvic symmetry).
(Am J Vet Res 2000;61:1031–1036)
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 characterize compensatory movements
of the head and pelvis that resemble lameness
Animals—17 adult horses.
Procedure—Kinematic evaluations were performed
while horses trotted on a treadmill before and after
shoe-induced lameness. Lameness was quantified
and the affected limb determined by algorithms that
measured asymmetry in vertical movement of the
head and pelvis. Induced primary lameness and compensatory
movements resembling lameness were
assessed by the Friedman test. Association between
induced lameness and compensatory movements
was examined by regression analysis.
Results—Compensatory movements resembling
lameness in the ipsilateral forelimb were seen with
induced lameness of a hind limb. There was less
downward and less upward head movement during
and after the stance phase of the ipsilateral forelimb.
Doubling the severity of lameness in the hind limb
increased severity of the compensatory movements
in the ipsilateral forelimb by 50%. Compensatory
movements resembling lameness of the hind limb
were seen after induced lameness in a forelimb.
There was less upward movement of the pelvis after
the stance phase of the contralateral hind limb and, to
a lesser extent, less downward movement of the
pelvis during the stance phase of the ipsilateral hind
limb. Doubling the severity of lameness in the forelimb
increased compensatory movements of the contralateral
hind limb by 5%.
Conclusions and Clinical Relevance—Induced
lameness in a hind limb causes prominent compensatory
movements resembling lameness in the ipsilateral
forelimb. Induced lameness in a forelimb causes
slight compensatory movements resembling
lameness in the ipsilateral and contralateral hind
limbs. (Am J Vet Res 2005;66:646–655)
Objective—To determine the effectiveness of administering multiple doses of phenylbutazone alone or a combination of phenylbutazone and flunixin meglumine to alleviate lameness in horses.
Animals—29 adult horses with naturally occurring forelimb and hind limb lameness.
Procedures—Lameness evaluations were performed by use of kinematic evaluation while horses were trotting on a treadmill. Lameness evaluations were performed before and 12 hours after administration of 2 nonsteroidal anti-inflammatory drug (NSAID) treatment regimens. Phenylbutazone paste was administered at approximately 2.2 mg/kg, PO, every 12 hours for 5 days, or phenylbutazone paste was administered at approximately 2.2 mg/kg, PO, every 12 hours for 5 days in combination with flunixin meglumine administered at 1.1 mg/kg, IV, every 12 hours for 5 days.
Results—Alleviation of lameness was greater after administration of the combination of NSAIDs than after oral administration of phenylbutazone alone. Improvement in horses after a combination of NSAIDs did not completely mask lameness. Five horses did not improve after either NSAID treatment regimen. All posttreatment plasma concentrations of NSAIDs were less than those currently allowed by the United States Equestrian Federation Inc for a single NSAID. One horse administered the combination NSAID regimen died of acute necrotizing colitis during the study.
Conclusions and Clinical Relevance—Administration of a combination of NSAIDs at the dosages and intervals used in the study reported here alleviated the lameness condition more effectively than did oral administration of phenylbutazone alone. This may attract use of combinations of NSAIDs to increase performance despite potential toxic adverse effects.
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.
Case Description—A 4-month-old Missouri Fox Trotter colt was examined for a 5-week history of head tilt after treatment for suspected pulmonary Rhodococcus equi infection.
Clinical Findings—Computed tomography revealed osteolysis of the occipital, temporal, and caudal portion of the parietal bones of the left side of the cranium. A soft tissue mass compressing the occipital region of the cerebral cortex and cerebellum was associated with the osteolytic bone.
Treatment and Outcome—A rostrotentorial-suboccipital craniectomy approach was performed to remove fragmented occipital bone, debulk the intracranial mass, and obtain tissue samples for histologic examination and bacterial culture. All neurologic deficits improved substantially within 3 days after surgery. Bacterial culture of the resected soft tissue and bone fragments yielded R equi.
Clinical Relevance—Intracranial surgery in veterinary medicine has been limited to dogs and cats; however, in select cases, extrapolation of surgical techniques used in humans and small animals can assist with intracranial procedures in horses.