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 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 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 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:
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)
Evaluation of the strength of the novel suture technique by comparison with a 2-interrupted suture technique.
40 equine larynges.
40 larynges were used; 16 laryngoplasties were performed using the currently accepted 2-suture technique and 16 using the novel suture technique. These specimens were subjected to a single cycle to failure. Eight specimens were used to compare the rima glottidis area achieved with 2 different techniques.
The mean force to failure, as well as the rima glottidis area of both constructs, were not significantly different. The cricoid width did not have a significant effect on the force to failure.
Our results suggest that both constructs are equally strong and can achieve a similar cross-sectional area of the rima glottidis. Laryngoplasty (“tie-back”) is currently the treatment of choice for horses with exercise intolerance due to recurrent laryngeal neuropathy. Failure to maintain the expected degree of arytenoid abduction post-surgery occurs in some horses. We believe this novel 2-loop pulley load-sharing suture technique can help achieve and, more importantly, maintain the desired degree of abduction during surgery.
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.
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 evaluate the effect of hemi-circumferential
periosteal transection and elevation (HCPTE) in
foals with experimentally induced angular limb deformities.
Animals—10 healthy foals.
Procedure—When foals were 30 days old, transphyseal
bridge implants were placed on the lateral
aspects of both distal radial physes. At 90 days of age
(or when 15 degrees of angulation had developed),
implants were removed, and HCPTE was performed
on 1 limb. Foals were confined in small pens after
surgery; the front feet of the foals were rasped weekly
to maintain medial-to-lateral hoof wall balance.
Dorsopalmar radiographic projections of the carpi
were obtained before HCPTE and 2, 4, 6, 8, and 48
Results—At the time of transphyseal bridge removal
and HCPTE, both treated and control limbs were
observed to have a significantly greater carpal valgus,
compared with the initial degree of angulation at 30
days of age. Following HCPTE or sham surgery, all
limbs straightened over the subsequent 2 months of
the study. Median angulation was not significantly different
between treated and control limbs at any time
during the study.
Conclusions and Clinical Relevance—Results suggest
that in foals with experimentally induced limb deformities,
HCPTE was no more effective than stall confinement
and hoof trimming alone for correction of the
deformity. (J Am Vet Med Assoc 2002;221:536–540)