Objective—To determine whether kinematic changes
induced by heel pressure in horses differ from those
induced by toe pressure.
Animals—10 adult Quarter Horses.
Procedure—A shoe that applied pressure on the
cuneus ungulae (frog) or on the toe was used.
Kinematic analyses were performed before and after 2
levels of frog pressure and after 1 level of toe pressure.
Values for stride displacement and time and joint angles
were determined from horses trotting on a treadmill.
Results—The first level of frog pressure caused
decreases in metacarpophalangeal (fetlock) joint extension
during stance and increases in head vertical movement
and asymmetry. The second level of frog pressure
caused these changes but also caused decreases in
stride duration and carpal joint extension during stance
as well as increases in relative stance duration. Toe pressure
caused changes in these same variables but also
caused maximum extension of the fetlock joint to occur
before midstance, maximum hoof height to be closer to
midswing, and forelimb protraction to increase.
Conclusion and Clinical Relevance—Decreased fetlock
joint extension during stance and increased head
vertical movement and asymmetry are sensitive indicators
of forelimb lameness. Decreased stride duration,
increased relative stance duration, and decreased
carpal joint extension during stance are general but
insensitive indicators of forelimb lameness. Increased
forelimb protraction, hoof flight pattern with maximum
hoof height near midswing, and maximum fetlock joint
extension in cranial stance may be specific indicators
of lameness in the toe region. Observation of forelimb
movement may enable clinicians to differentiate lameness
of the heel from lameness of the toe. (Am J Vet Res 2000;61:612-619)
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 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 evaluate the efficacy and safety of intra-articular administration of ethyl alcohol for arthrodesis of tarsometatarsal joints in horses.
Animals—8 healthy female horses without lameness or radiographic evidence of tarsal joint osteoarthritis.
Procedure—In each horse, 1 tarsometatarsal joint was treated with 4 mL of 70% ethyl alcohol and the opposite joint was treated with 4 mL of 95% ethyl alcohol. Lameness examinations were performed daily for 2 weeks, followed by monthly evaluations for the duration of the 12-month study. Radiographic evaluations of both tarsi were performed 1 month after injection and every 3 months thereafter. Gross and histologic examinations of the tarsi were undertaken at completion of the study.
Results—Horses had minimal to no lameness associated with the treatments. Radiography revealed that 8 of 16 joints were fused by 4 months after treatment, with significantly more joints fused in the 70% ethyl alcohol group. Fifteen of 16 joints were considered fused at postmortem examination at 12 months. Gross and histologic examinations revealed foci of dense mature osteonal bone spanning the joint spaces. Bony fusion appeared to be concentrated on the dorsolateral, centrolateral, and plantarolateral aspects of the joints. Significant differences were not detected between treatment groups for lameness or pathologic findings.
Conclusions and Clinical Relevance—Administration of ethyl alcohol into the tarsometatarsal joint of healthy horses appeared to facilitate arthrodesis of the joint in a pain-free manner. Results warrant further investigation into the potential use of ethyl alcohol in horses clinically affected with osteoarthritis of the tarsometatarsal and distal intertarsal joints.
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 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 compare induction and recovery characteristics
and cardiopulmonary effects of isoflurane
and sevoflurane in foals.
Design—Prospective crossover study.
Animals—6 healthy foals.
Procedure—Foals were anesthetized twice (once at
1 month of age and again at 3 months of age).
Anesthesia was induced by administration of the
agent in oxygen through a nasotracheal tube. During
maintenance of anesthesia, foals were positioned in
dorsal recumbency; intermittent positive-pressure
ventilation was performed. Characteristics of induction
and recovery were recorded. Cardiopulmonary
variables were recorded 10 minutes after anesthetic
induction and 15, 30, 45, and 60 minutes later.
Results—All 6 foals were successfully anesthetized
with isoflurane and sevoflurane. There were no significant
differences between the 2 drugs in regard to
characteristics of induction or recovery, and induction
and recovery were generally smooth and unremarkable.
There were no significant differences between
drugs in regard to measured cardiopulmonary variables;
however, both drugs caused initial hypotension
that resolved over time.
Conclusions and Clinical Relevance—Results suggest
that isoflurane and sevoflurane can both be used
for general anesthesia of 1- to 3-month-old foals.
Significant differences between the 2 agents were
not detected for any of the variables measured, suggesting
that quality of anesthesia with these 2 agents
was comparable. (J Am Vet Med Assoc 2002;221:
To compare laryngeal impedance, in terms of air flow and pressure, following arytenoid corniculectomy (COR) versus 3 other airway interventions (left-sided laryngoplasty with ipsilateral ventriculocordectomy [LLP], LLP combined with COR [LLPCOR], and partial arytenoidectomy [PA]) performed on cadaveric equine larynges with simulated left recurrent laryngeal neuropathy (RLN) and to determine whether relative laryngeal collapse correlated with the interventions performed.
28 cadaveric equine larynges.
Each larynx in states of simulated left RLN alone and with airway interventions in the order LLP, LLPCOR, COR, and PA was evaluated in a box model construct that replicated upper airway flow mechanics consistent with peak exercise in horses. Results for impedance, calculated from airflow and pressure changes, were compared between states for each larynx. Multivariable mixed-effects analysis controlling for repeated measures within larynx was performed to calculate the predicted mean impedance for each state.
Results indicated that tracheal adapter diameter, individual larynx properties, airway intervention, and relative laryngeal collapse affected laryngeal impedance. The LLP and LLPCOR interventions had the lowest impedance, whereas the COR and PA interventions did not differ substantially from the simulated left RLN state. Residual intraclass correlation of the model was 27.6 %.
CONCLUSIONS AND CLINICAL RELEVANCE
Although impedance was higher for the simulated left RLN with the COR intervention state than with the LLP intervention state, given the clinical success of PA for treating RLN in horses and the similar results for the COR and PA intervention states in the present study, the use of COR warrants further investigation. The residual interclass correlation suggested that individual laryngeal variation affected impedance and may have a clinical effect.
To compare results for initial body-mounted inertial sensor (BMIS) measurement of lameness in equids trotting in a straight line with definitive findings after full lameness evaluation.
Lameness measured with BMIS equipment while trotting in a straight line was classified into categories of none, forelimb only, hind limb only, and 8 patterns of combined forelimb and hind limb lameness (CFHL). Definitive findings after full lameness evaluation were established in most horses and classified into types (no lameness, forelimb- or hind limb–only lameness, CFHL, or lameness not localized to the limbs). Observed proportions of lameness type in equids with definitive findings for each initial BMIS-assessed category were compared with hypothetical expected proportions through χ2 goodness-of-fit analysis.
The most common initial BMIS-assessed lameness category was CFHL (693/1,224 [56.6%]), but this was the least common definitive finding (94/ 862 [10.9%]). The observed frequency of no lameness after full lameness evaluation was greater than expected only when initial BMIS measurements indicated no lameness. The observed frequency of forelimb-only lameness was greater than expected when initially measured as forelimb-only lameness and for CFHL categories consistent with the diagonal movement principle of compensatory lameness. Observed frequency of hind limb–only lameness was greater than expected when initially measured as hind limb–only lameness and for CFHL categories consistent with the sagittal movement principle of compensatory lameness. Equids initially assessed as having no lameness had the highest (103/112 [92%]) and those assessed as CFHL pattern 7 (forelimb with contralateral hind limb impact-only lameness) had the lowest (36/66 [55%]) rates of definitive findings.
CONCLUSIONS AND CLINICAL RELEVANCE
In equids, results of initial straight-line trotting evaluations with a BMIS system did not necessarily match definitive findings but may be useful in planning the remaining lameness evaluation.
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.