Objective—To evaluate mediolateral, axial, torsional,
and craniocaudal bending behavior of 6 distal ring-block
configurations commonly used to stabilize short
juxta-articular bone segments in small animals.
Sample Population—8 circular external skeletal fixator
constructs of each of 6 distal ring-block configurations.
The distal ring-block configurations were composed
of combinations of complete rings, incomplete
rings, and drop wires.
Procedure—Constructs were nondestructively
loaded in axial compression, craniocaudal bending,
mediolateral bending, and torsional loading by use of
a materials testing machine. Gap stiffness was determined
by use of the resultant load displacement
Results—Circular external skeletal fixator configurations
and constructs significantly affected gap stiffness
in all testing modes. Within each loading mode,
gap stiffness was significantly different among most
configurations. In general, complete ring configurations
were significantly stiffer than similar incomplete
ring configurations, and addition of a drop wire to a
configuration significantly increased stiffness of that
Conclusions and Clinical Relevance—When regional
anatomic structures permit, the use of complete
ring configurations is preferred over incomplete ring
configurations. When incomplete ring configurations
are used, the addition of a drop wire is recommended.
(Am J Vet Res 2004;65:393–398)
Objective—To compare preoperative administration
of meloxicam and butorphanol to perioperative administration
of butorphanol alone for control of postoperative
signs of pain in dogs.
Animals—40 client-owned dogs scheduled for surgical
repair of a cranial cruciate ligament rupture.
Procedure—Group-1 dogs received butorphanol (0.2
mg/kg, IV) and meloxicam (0.2 mg/kg, IV) just prior to
surgery. Group-2 dogs received butorphanol just prior
to surgery (0.2 mg/kg, IV) and at incision closure (0.1
mg/kg, IV). Pain assessment began 1 to 2 hours
before surgery and from extubation until 24 hours
after surgery by obtaining the following measurements:
the visual analog scale (VAS) score, cumulative
pain score (CPS), adjusted cumulative pain score,
modified cumulative pain score, and the adjusted
modified cumulative pain score (AMCPS). Serum cortisol
concentration was measured between 12 to 24
and between 1 to 2 hours prior to surgery, and at 30
minutes, and 1, 2, 4, 8, 18, and 24 hours after extubation.
Results—No significant differences between treatment
groups were observed in CPS or VAS score. At
8, 9, 10, and 11 hours after extubation, meloxicambutorphanol-
treated dogs had a significantly lower
AMCPS, compared with butorphanol-alone-treated
dogs. Total serum cortisol concentration (area under
the curve) during the measurement period was significantly
lower in meloxicam-butorphanol-treated
dogs, compared with butorphanol-alone treated dogs.
Conclusions and Clinical Relevance—Preoperative
single dose administration of meloxicam-butorphanol
is equivalent to or slightly better than the administration
of 2 perioperative doses of butorphanol for the
control of postoperative signs of pain in dogs. (Am J
Vet Res 2002;63:1557–1563)
Objective—To determine relative effects of ring
diameter and wire tension on axial biomechanical
properties of 4-ring circular external skeletal fixator
Sample Population—4-ring circular external skeletal
fixator constructs and artificial bone models.
Procedure—4-ring constructs were assembled,
using 50-, 66-, 84-, or 118-mm-diameter rings. Two
1.6-mm-diameter fixation wires were attached to
opposing surfaces of each ring at intersection angles
of 90o and placed through a gap-fracture bone model.
Three examples of each construct were loaded in
axial compression at 7 N/s to a maximum load of 400
N at each of 4 wire tensions (0, 30, 60, and 90 kg).
Response variables were determined from resulting
load-displacement curves (construct stiffness, load at
1 mm of displacement, displacement at 400 N).
Results—Ring diameter and wire tension had a significant
effect on all response variables and had a significant
interaction for construct stiffness and displacement
at 400 N. Significant differences within all
response variables were seen among all 4 ring diameters
and all 4 wire tensions. As ring diameter
increased, effect of increasing wire tension on gap
stiffness and gap displacement at 400 N decreased.
Ring diameter had a greater effect than wire tension
on all response variables.
Conclusions and Clinical Relevance—Although
effects of wire tension decrease as ring diameter
increases, placing tension on wires in larger ring constructs
is important because these constructs are
inherently less stiff. The differential contribution of
ring diameter, wire tension, and their interactions
must be considered when using circular external
skeletal fixators. (Am J Vet Res 2001;62:1025–1030)
Objective—To describe a percutaneously controlled
static hydraulic urethral sphincter (SHUS) and evaluate
urodynamic effects of the SHUS in canine cadavers.
Sample Population—Cadavers of 6 adult female
Procedure—Cadavers were obtained immediately
after dogs were euthanatized. Baseline maximal urethral
closure pressure (MUCP) and cystourethral leak
point pressure (CLPP) were measured by use of a
urethral pressure profilometer. An SHUS system was
constructed by use of a silicone vascular occluder and
subcutaneous infusion port. The SHUS system was
then placed around the pelvic urethra in each cadaver.
Measurements of MUCP and CLPP were repeated
after varying occlusion of the SHUS (0%, 25%, and
50% occlusion). Baseline MUCP and CLPP values
were compared with values obtained at 0%, 25%,
and 50% occlusion of the SHUS by use of repeatedmeasures
Results—Mean ± SD MUCP for canine cadavers was
7 ± 1.3 cm H2O at baseline, which increased to 127 ±
53 cm H2O after 50% occlusion of the SHUS. Mean
CLPP was 11 ± 8.6 cm H2O at baseline, which
increased to 73 ± 38 cm H2O after 50% occlusion of
the SHUS. Mean MUCP and CLPP were significantly
associated with the amount of occlusion.
Conclusions and Clinical Relevance—The SHUS
had positive effects on MUCP and CLPP in canine
cadavers. Therefore, additional evaluation of the
SHUS in live dogs is warranted. ( Am J Vet Res 2004;
Objective—To compare the axial stiffness, maximum axial displacement, and ring deformation during axial loading of single complete and incomplete circular (ring) external skeletal fixator constructs.
Sample—32 groups of single ring constructs (5 constructs/group).
Procedures—Single ring constructs assembled with 2 divergent 1.6-mm-diameter Kirschner wires were used to stabilize a 60-mm-long segment of 16-mm-diameter acetyl resin rod. Construct variables included ring type (complete or incomplete), ring diameter (50, 66, 84, or 118 mm), and fixation wire tension (0, 30, 60, or 90 kg). Axial loading was performed with a materials testing system. Construct secant stiffness and maximum displacement were calculated from the load-displacement curves generated for each construct. Ring deformation was calculated by comparing ring diameter during and after construct loading to ring diameter prior to testing.
Results—Complete ring constructs had greater axial stiffness than did the 66-, 84-, and 118-mm-diameter incomplete ring constructs. As fixation wire tension increased, construct stiffness increased in the 66-, 84-, and 118-mm-diameter incomplete ring constructs. Maximum axial displacement decreased with increasing fixation wire tension, and complete ring constructs allowed less displacement than did incomplete ring constructs. Incomplete rings were deformed by wire tensioning and construct loading.
Conclusions and Clinical Relevance—Mechanical performance of the 66-, 84-, and 118-mm-diameter incomplete ring constructs improved when wire tension was applied, but these constructs were not as stiff as and allowed greater displacement than did complete ring constructs of comparable diameter. For clinical practice, tensioning the wires placed on 84- and 118-mm-diameter incomplete rings to 60 kg is recommended.
Objective—To compare radius of curvature along the
ulnar trochlear notch of Rottweilers and Greyhounds
to determine whether morphologic differences exist
that may contribute to the cause and pathogenesis of
fragmented coronoid process in Rottweilers.
Sample Population—Paired elbow joints from 13
Rottweilers and 14 Greyhounds.
Procedure—Elbow joints were radiographically
scored on the basis of severity of osteoarthritic
lesions. The articular contour of each ulnar trochlear
notch was digitized. The radius of curvature at
defined points along the ulnar trochlear notch was
compared between breeds.
Results—Radius of curvature of the ulnar trochlear
notch was not a constant function of arc length in
either breed but had a consistent characteristic
appearance in both breeds. Radius of curvature was
greatest at each end of the ulnar trochlear notch and
had 2 peaks in the midportion of the notch in both
breeds. These peaks occurred farther distally in the
notch and were larger in Rottweiler ulnae than
Greyhound ulnae. A significant difference in mean
radius of curvature was detected between breeds at
these peaks. Greyhounds had significantly greater
mean radius of curvature at the end of the medial
coronoid process, compared with Rottweilers.
Conclusions and Clinical Relevance—Radius of curvature
of the ulnar trochlear notch is a complex function
of arc length in Rottweilers and Greyhounds. The
waveform has a consistent characteristic appearance
in both breeds. Although significant differences were
identified between breeds, associations between
these differences and cause or pathogenesis of fragmented
coronoid process in Rottweilers were not
apparent. ( Am J Vet Res 2001; 62:968–973)
Animals—38 client-owned dogs with osteoarthritis examined at 2 university veterinary clinics.
Procedures—Dogs were randomly assigned to receive a typical commercial food (n = 16) or a test food (22) containing 3.5% fish oil omega-3 fatty acids. On day 0 (before the trial began) and days 45 and 90 after the trial began, investigators conducted orthopedic evaluations and force-plate analyses of the most severely affected limb of each dog, and owners completed questionnaires to characterize their dogs' arthritis signs.
Results—The change in mean peak vertical force between days 90 and 0 was significant for the test-food group (5.6%) but not for the control-food group (0.4%). Improvement in peak vertical force values was evident in 82% of the dogs in the test-food group, compared with 38% of the dogs in the control-food group. In addition, according to investigators' subjective evaluations, dogs fed the test food had significant improvements in lameness and weight bearing on day 90, compared with measurements obtained on day 0.
Conclusions and Clinical Relevance—At least in the short term, dietary supplementation with fish oil omega-3 fatty acids resulted in an improvement in weight bearing in dogs with osteoarthritis.