Objective—To assess different components of the
extracellular matrix with regard to their thermal properties,
composition, and turnover in ruptured cranial
cruciate ligaments (CCLs) of dogs, compared with
components of intact CCLs from a breed predisposed
to CCL failure.
Sample Population—Ruptured CCLs obtained from
8 dogs of breeds predisposed to ruptured CCLs and
intact CCLs from 12 cadaveric Labrador Retrievers.
Procedure—Ruptured and intact CCLs were analyzed
for water content; collagen content and collagen
cross-links were evaluated via hydroxyproline and
amino-acid analyses, respectively. Glycosaminoglycan
(GAG) content was analyzed via dimethylmethylene
blue and uronic acid assays. Matrix metalloproteinases
(MMPs)-2 and -9 and the tissue inhibitors of metalloproteinases
(TIMPs)-1 and -2 were detected via
gelatin SDS-PAGE zymography and reverse gelatin
zymography. Thermal analysis of ligaments was performed
by use of differential scanning calorimetry.
Results—Ruptured CCLs had significantly higher lamounts
of immature cross-links, total and sulfated GAGs,
and water content, compared with that of the intact ligaments.
Compared with intact CCLs, concentration of
pro–MMP-2 was significantly higher in ruptured CCLs;
the maximum temperature of collagen denaturation
was significantly lower in the ruptured CCLs.
Conclusions and Clinical Relevance—The extracellular
matrix of ruptured CCLs had an increased matrix
turnover indicated by increased collagen and GAG synthesis,
compared with that of intact CCLs. Although
the extracellular matrix changes may have occurred
before ligament rupture, it is possible that these
observed changes may be part of a reparative process
after rupture. (Am J Vet Res 2004;65:1136–1141)
To compare the attenuation of the medial coronoid process (MCP) in dogs with and without arthroscopically confirmed evidence of medial coronoid disease (MCD).
The database at our institution was searched for cases with thoracic limb lameness, diagnosed with MCD by arthroscopic examination that had CT as part of their investigation and compared with a control group of elbow joints from cadavers euthanized for reasons unrelated to MCD. A total of 84 elbow joints were included that met these criteria.
Following CT, a standardized measurement of the MCP was obtained from apex to base and the mean attenuation, SD, and total area were recorded. A comparative measurement was obtained from the proximal radial cortex at the level of the nutrient foramen. Elbow joint arthroscopy was carried out using standard portals, and the modified Outerbridge score was (MOS) used to score elbow joint cartilage. Descriptive and inferential statistics were carried out using MLwiN and R.
Attenuation of the MCP was reduced in dogs with MCD compared with those with no MCD (P < .002). No significant differences were observed in the attenuation between categories of severity (MOS). There was good inter- and intraobserver agreement between measurements (intraclass correlation coefficient = 0.89 and 0.95, respectively).
MCP attenuation is reduced in dogs with MCD compared with dogs with no evidence of MCD. This finding may be a useful tool for early detection of MCD, but there is no relationship with arthroscopic lesion severity.
Objective—To quantify angular excursions; net joint
moments; and powers across the stifle, tarsal, and
metatarsophalangeal (MTP) joints in Labrador
Retrievers and Greyhounds and investigate differences
in joint mechanics between these 2 breeds of
Animals—12 clinically normal dogs (6 Greyhounds
and 6 Labrador Retrievers) with no history of hind
Procedure—Small retroreflective markers were
applied to the skin over the pelvic limb joints, and a 4-
camera kinematic system captured data at 200 Hz in
tandem with force platform data while the dogs trotted
on a runway. Breed-specific morphometric data
were combined with kinematic and force data in an
inverse-dynamics solution for stance-phase net joint
moments and powers at the stifle, tarsal, and MTP
Results—There were gross differences in kinematic
patterns between Greyhounds and Labradors. At the
stifle and tarsal joints, moment and power patterns
were similar in shape, but amplitudes were larger for
the Greyhounds. The MTP joint was a net absorber of
energy, and this was greater in the Greyhounds.
Greyhounds had a positive phase across the stifle,
tarsal, and MTP joints at the end of stance for an
active push-off, whereas for the Labrador Retrievers,
the only positive phase was across the tarsus, and
this was small, compared with values for the
Conclusions and Clinical Relevance—Gross differences
in pelvic limb mechanics are evident between
Greyhounds and Labrador Retrievers. Joint kinetics in
specific dogs should be compared against breed-specific
patterns. (Am J Vet Res 2005;66:1563–1571)