Objective—To determine whether a full-body spandex
garment would alter rectal temperatures of
healthy dogs at rest in cool and warm environments.
Animals—10 healthy dogs.
Procedures—Each dog was evaluated at a low (20° to
25°C [68° to 77°F]) or high (30° to 35°C [86° to 95°F])
ambient temperature while wearing or not wearing a
commercially available whole-body spandex garment
designed for dogs. Oxygen consumption was measured
by placing dogs in a flow-through indirect
calorimeter for 90 to 120 minutes. Rectal temperature
was measured before dogs were placed in the
calorimeter and after they were removed.
Results—Rectal temperature increased significantly
more at the higher ambient temperature than at the
lower temperature and when dogs were not wearing
the garment than when they were wearing it. The
specific rate of oxygen consumption was significantly
higher at the lower ambient temperature than at the
Conclusions and Clinical Relevance—Results suggest
that wearing a snug spandex body garment does
not increase the possibility that dogs will overheat
while in moderate ambient temperatures. Instead,
wearing such a garment may enable dogs to better
maintain body temperature during moderate heat
loading. These results suggest that such garments
might be used for purposes such as wound or suture
protection without causing dogs to overheat. (J Am
Vet Med Assoc 2004;224:71–74)
Objective—To compare fit and geometry of reconstruction
of femoral components of 4 canine cemented
total hip replacement implants and determine
which implants are most compatible with current principles
of cemented arthroplasty.
Sample Population—Paired femurs from 16 adult
Procedure—Femurs were prepared for femoral stem
implantation of either the Bardet, BioMedtrix,
Mathys, or Richards II implant. Mediolateral and craniocaudal
radiographs were obtained with femoral
components in situ. Cross-sectional analysis of
implant fit was performed on transected cemented
specimens. Computer-aided analyses of digitized
images were performed.
Results—The Bardet and Richards II implants
reconstructed the original femoral head position significantly
better than the other 2 implants. None of
the implants allowed neutralization of the implant
axis in the sagittal plane or were routinely centralized
in the femoral canal. The Bardet implant had the
smallest minimum distal tip offset in the sagittal
plane. Greatest tip to cortex distance was provided
by the Richards II implant in the transverse plane
and the Mathys implant in the sagittal plane. The
thinnest cement mantle regions for all implants
were in the central longitudinal third of the femoral
Conclusions and Clinical Relevance—The Bardet
and BioMedtrix implants had stem design characteristics
that were most compatible with principles of
cemented stem fixation. None of the implants completely
satisfied the theoretically optimal conditions of
centralization and neutralization of the femoral stem.
Innovative design modifications, therefore, may be
needed if these conditions are important to the longterm
success of canine total hip replacement. (Am J
Vet Res 2000;61:1113–1121)
Objective—To evaluate areas of articular contact of
the proximal portions of the radius and ulna in normal
elbow joints of dogs and the effects of axial load on
size and location of these areas.
Sample Population—Forelimbs obtained from
cadavers of 5 adult mixed-breed dogs.
Procedure—After forelimbs were removed, liquidphase
polymethyl methacrylate was applied to articular
surfaces of the elbow joint, and limbs were axially
loaded. Articular regions void of casting material were
stained with water-soluble paint. Relative articular contact
areas were determined by computer-assisted
image analyses of stained specimens. Repeatability of
the technique was evaluated by analyses of casts from
bilateral forelimbs of 1 cadaver. Incremental axial loads
were applied to left forelimbs from 4 cadavers to
determine effects of load on articular contact.
Results—Specific areas of articular contact were
identified on the radius, the craniolateral aspect of the
anconeus, and the medial coronoid process. The
medial coronoid and radial contact areas were continuous
across the radioulnar articulation. There was no
articular contact of the medial aspect of the anconeus
with the central trochlear notch. Coefficients of variation
of contact areas between repeated tests and
between contralateral limbs was < 20%. Significant
overall effects of axial load on contact area or location
were not identified.
Conclusions—Three distinct contact areas were evident
in the elbow joint of dogs. Two ulnar contact
areas were detected, suggesting there may be physiologic
incongruity of the humeroulnar joint. There
was no evidence of surface incongruity between the
medial edge of the radial head and the lateral edge of
the medial coronoid process. (Am J Vet Res 2000;61:
Objective—To develop a model for measuring rotary
stability of the canine elbow joint and to evaluate the
relative contribution of the anconeal process (AN), lateral
collateral ligament (LCL), and medial collateral ligament
Sample Population—18 forelimbs from 12 canine
Procedure—Forelimbs were allocated to 3 experimental
groups (6 forelimbs/group). Each intact forelimb
was placed in extension at an angle of 135° and
cycled 50 times from –16° (pronation) to +28° (supination)
in a continuous manner at 2.0 Hz. Cycling was
repeated following sectioning of the structure of interest
(group 1, AN; group 2, LCL; and group 3, MCL).
Torque at –12° (pronation) and +18° (supination) was
measured for each intact and experimentally sectioned
limb. A Student t test was performed to compare
torque values obtained from intact verses experimentally
sectioned limbs and for comparison with
established criteria for differentiation of primary
(≥ 33%), secondary (10 to 33%), and tertiary rotational
stabilizers (< 10%).
Results—In pronation, the AN was the only primary
stabilizer (65%). For supination, the LCL was a primary
stabilizer (48%), AN was a secondary stabilizer
(24%), and MCL was a tertiary stabilizer (7%).
Conclusions and Clinical Relevance—With the
elbow joint in extension at an angle of 135°, the AN is
a primary rotational stabilizer in pronation, and the
LCL is a primary stabilizer in supination. Disruption of
the AN or LCL may affect rotary range of motion or
compromise stability of the elbow joint in dogs.
(Am J Vet Res 2002;63:1520–1526)
Objective—To determine effects of incremental radial
shortening and subsequent ulnar ostectomies on joint
surface contact patterns in a canine elbow joint model.
Sample Population—Paired forelimbs from 9 adult
Procedure—Joint casting was performed by placement
of colored polymethylmethacrylate in the elbow
joint cavity and loading in a materials testing system
at physiologic angle and load. Joint casting was performed
in unaltered specimens, after radial shortening,
and after subsequent distal ulnar ostectomy,
proximal ulnar ostectomy, and proximal ulnar ostectomy
with intramedullary pinning. Computer-aided
analysis of photographs of proximal radial and ulnar
articular surfaces without joint casts was performed
before and after each casting procedure.
Results—All increments of radial shortening changed
the size and location of radial and ulnar contact areas.
The radial contact area became smaller, the anconeal
contact area disappeared, the medial coronoid contact
area migrated craniolaterally, and the lateral projection
of the coronoid process became a contact area. A proximal
ulnar ostectomy stabilized with an intramedullary
pin restored normal contact area size and location and
restored continuity of the radial and coronoid contact
areas across the radioulnar articulation in 6 of 10 specimens.
A midshaft ulnar ostectomy, distal to the level of
the radioulnar ligament, had no effect on contact patterns.
A proximal ulnar ostectomy without stabilization
resulted in varus deformity during loading.
Conclusion and Clinical Relevance—Proximal radial
shortening, which creates articular step incongruity,
changes the location and size of the radioulnar contact
areas. Dynamically stabilized ulnar ostectomies
proximal to the radioulnar ligament restore contact
patterns in vitro . (Am J Vet Res 2001;62:1548–1556)
Objective—To compare in vitro mechanical properties
of toggle pins and toggle rods used as suture
anchors and of 3 suture materials (50-lb monofilament
polybutester, No. 5 braided polyester, and 5-mm
woven polyester) commonly used as prosthetic ligaments
in the repair of hip joint luxation in dogs.
Sample Population—Femoropelvic specimens from
the cadavers of 18 dogs.
Procedure—Suture anchors were compared by use
of pullout tests. Suture materials were compared by
use of monotonic and cyclic tensile tests; cyclic tensile
tests were performed with the suture placed over
the edge of an aluminum bar to simulate the edge of
the femoral bone tunnel. In vitro mechanical properties
of the ligament of the femoral head were determined
by use of monotonic tensile tests, using boneligament-bone cadaveric specimens. The in vitro
mechanical properties of the acetabulum-ligamentfemur
complex and of this complex following rupture
of the ligament and stabilization with a toggle rod and
5-mm woven polyester were determined by use of
compression tests that simulated weight-bearing.
Results—Mechanical properties of the toggle rod
were not significantly different from those of the toggle
pin. Woven polyester had the longest fatigue life
in cyclic testing. Hip joints stabilized with a toggle rod
and woven polyester had less than half the strength
in vitro of intact joints.
Conclusions and Clinical Relevance—Results suggested
that a toggle rod or toggle pin can be used for
stabilization of hip joint luxations in dogs. Of the
materials tested, braided polyester had the best in
vitro mechanical properties. (Am J Vet Res 2001;62:
Objective—To evaluate subchondral bone density patterns
in elbow joints of clinically normal dogs by use of
computed tomographic (CT) osteoabsorptiometry.
Sample Population—20 cadaver forelimbs from 10
clinically normal dogs.
Procedure—Each elbow joint was imaged in
parasagittal and transverse planes of 1.5-mm thickness.
Slice data were converted to dipotassium phosphate
equivalent density (PPED) values. Sagittal,
parasagittal, and transverse medial coronoid process
topographic maps were constructed. Defined zones
were created for each of the 3 CT planes, and confluence
and peak PPED values were determined.
Results—The lowest PPED value was 340 mg/ml
(articular and subchondral confluence), and the highest
was 1780 mg/ml (peak subchondral density).
Detectable effects of joint laterality were not found in
the confluence or peak PPED measurements or in the
peak-to-confluence PPED ratio for all 3 CT planes.
Significant differences were found among zones in all
3 planes for confluence and peak PPED measurements
and between sagittal and transverse planes for
peak-to-confluence PPED ratios. Subjectively, the pattern
of density distribution among dogs was fairly
consistent for the sagittal and parasagittal slices.
Three specific patterns of density distribution were
apparent on the transverse topographic maps of the
medial coronoid process that corresponded to conformational
Conclusions and Clinical Relevance—The use of CT
osteoabsorptiometry provides a repeatable technique
that can be used to noninvasively examine bone density
and the effects of stress acting on joints in vivo.
Variability in density values for any of the CT planes
was not identified among clinically normal dogs.
(Am J Vet Ress 2002;63:1159–1166
Procedure—Joint casting was performed by placement
of colored polymethylmethacrylate in the elbow
joint cavity followed by loading in a materials testing
system at physiologic angle and load. Joint casting
was performed in unaltered specimens, after 10°
medial opening wedge osteotomy, and after lateral
sliding osteotomy of the proximal portion of the
humerus. Computer-aided analysis of photographs of
proximal radial and ulnar articular surfaces after each
casting procedure was performed.
Results—The lateral sliding humeral osteotomy and
10° medial opening wedge osteotomy significantly
altered joint surface contact regions of the canine
elbow joint. Osteotomies resulted in a reduction in
the size of the radial, ulnar, and combined radioulnar
contact areas. Both osteotomies also resulted in craniolateral
migration of the radial contact area and craniomedial
recession of the ulnar contact area. Although
the reduction in ulnar contact area with these treatments
is consistent with our hypotheses, the reduction
in radial contact area was not anticipated.
Conclusions and Clinical Relevance—Humeral
osteotomies alter joint surface contact areas of the
canine elbow joint in vitro. Humeral osteotomies may
decrease contact areas on the diseased region of the
joint in dogs with elbow dysplasia; however, the overall
decrease in joint surface contact area suggests
that these procedures may induce focal increases in
pressure that may cause iatrogenic cartilage damage
when applied in vivo. (Am J Vet Res 2003;64:506–511)
Objective—To calculate normative joint angle, intersegmental
forces, moment of force, and mechanical
power at elbow, antebrachiocarpal, and metacarpophalangeal
joints of dogs at a walk.
Animals—6 clinically normal mixed-breed dogs.
Procedure—Kinetic data were collected via a force
platform, and kinematic data were collected from
forelimbs by use of 3-dimensional videography.
Length, location of the center of mass, total mass,
and mass moment of inertia about the center of mass
were determined for each of 4 segments of the forelimb.
Kinematic data and inertial properties were combined
with vertical and craniocaudal ground reaction
forces to calculate sagittal plane forces and moments
across joints of interest throughout stance phase.
Mechanical power was calculated as the product of
net joint moment and the angular velocity. Joint
angles were calculated directly from kinematic data.
Results—All joint intersegmental forces were similar
to ground reaction forces, with a decrease in magnitude
the more proximal the location of each joint.
Flexor moments were observed at metacarpophalangeal
and antebrachiocarpal joints, and extensor
moments were observed at elbow and shoulder
joints, which provided a net extensor support
moment for the forelimb. Typical profiles of work
existed for each joint.
Conclusions and Clinical Relevance—For clinically
normal dogs of a similar size at a walk, inverse
dynamic calculation of intersegmental forces,
moments of force, and mechanical power for forelimb
joints yielded values of consistent patterns and magnitudes.
These values may be used for comparison in
evaluations of gait in other studies and in treatment of
dogs with forelimb musculoskeletal disease. (Am J Vet Res 2003;64:609–617)
Objective—To investigate the biomechanics of cervical
vertebral motion units (VMUs) before and after a
ventral slot procedure and after subsequent pin-polymethylmethacrylate
(pin-PMMA) fixation and to
assess the use of smooth and positive-profile threaded
(PPT) pins in pin-PMMA fixation and intravertebral
Sample Population—Cervical portions (C3 through
C6 vertebrae) of 14 cadaveric canine vertebral
Procedure—Flexion and extension bending moments
were applied to specimens before and after creation
of a ventral slot across the C4-C5 intervertebral space
and after subsequent smooth or PPT pin-PMMA fixation
at that site. Data for the C3-C4, C4-C5, and C5-C6
VMUs were compared among treatments and
between pin types, and pin protrusion was compared
between pin types.
Results—Compared with values in intact specimens,
ventral slot treatment increased neutral zone range of
motion (NZ-ROM) by 98% at the treated VMUs and
appeared to decrease overall ROM at adjacent VMUs;
pin-PMMA fixation decreased NZ-ROM by 92% at the
treated VMUs and increased overall NZ-ROM by 19%
to 24% at adjacent VMUs. Specimens fixed with PPT
pins were 82% (flexion) and 80% (extension) stiffer
than smooth–pin-fixed specimens. Overall, 41% of
pins protruded into foramina; PPT pins were more
likely to protrude into transverse foramina.
Conclusions and Clinical Relevance—Results indicated
that fixation of a cervical VMU alters the biomechanics
of adjacent VMUs and may contribute to
degeneration of adjacent intervertebral disks. Use of
threaded pins may lower the incidence of pin loosening
and implant failure but enhances the likelihood of
transverse foramina penetration. ( Am J Vet Res 2005;66:678–687)