Objective—To determine localization of tartrate-resistant
acid phosphatase (TRAP) and cathepsin K in ruptured
and healthy cranial cruciate ligaments (CCL) in
Animals—30 dogs with ruptured CCL, 8 aged dogs
without ruptured CCL, and 9 young dogs without ruptured
Procedure—The CCL was examined histologically
and cells containing TRAP and cathepsin K were identified
histochemically and immunohistochemically,
Results—Cathepsin K and TRAP were detected within
the same cells, principally within the epiligamentous
region and to a lesser extent in the core region
of ruptured CCL. Numbers of cells containing TRAP
and cathepsin K were significantly greater in ruptured
CCL, compared with CCL from young or aged dogs,
and numbers of such cells were greater in CCL from
aged dogs, compared with those of young dogs. In
aged dogs, small numbers of cells containing TRAP
and cathepsin K were seen in intact CCL associated
with ligament fascicles in which there was chondroid
transformation of ligament fibroblasts and disruption
of the extracellular matrix.
Conclusion and Clinical Relevance—Ruptured
CCL contain greater numbers of cells with the proteinases
TRAP and cathepsin K than CCL from
healthy, young, or aged dogs. Results suggest that
cell-signaling pathways that regulate expression of
these proteinases may form part of the mechanism
that leads to upregulation of collagenolytic ligament
remodeling and progressive structural failure of the
CCL over time. (Am J Vet Res 2002;63:1279–1284).
Objective—To describe the cancellous bone architecture
of the head and neck of the femur in healthy
dogs by use of automated histomorphometry techniques
in conjunction with histologic grading of articular
Animals—30 mature male dogs with healthy coxofemoral
Procedure—Dogs were 1.5 to 4 years old and
weighed 27 to 37 kg. Computer images of fine-detail
radiographs of 100-µm-thick coronal and transverse
plane sections of the head and neck of the femur
(14 dogs) were analyzed by use of histomorphometry
software. Statistical comparisons among histomorphometric
indices of 4 regions were performed.
Histologic preparations of coronal and transverse
plane sections of femoral head articular cartilage
(16 dogs) were graded. Median grades for lateral,
medial, cranial, and caudal halves of the femoral head
articular cartilage were determined.
Results—Bone volume/total volume, trabecular thickness
and number, and bone surface/total volume were
significantly higher in the femoral head than in the
femoral neck. Anisotropy (trabecular alignment) and
trabecular separation were significantly higher in the
femoral neck than in the femoral head. Anisotropy was
significantly higher in the caudal half of the femoral
neck than in the cranial half. Cartilage had histologic
grades indicating health without significant differences
among lateral, medial, cranial, and caudal halves of
femoral head cartilage.
Conclusions and Clinical Relevance—A predictable
cancellous architecture in the head and neck of the
femur is associated with healthy cartilage. (Am J Vet
Objective—To describe cancellous architecture of the
proximal portion of the femur in dogs with osteoarthritis.
Animals—30 dogs with coxofemoral osteoarthritis.
Procedure—All dogs had femoral head and neck excision
or total hip arthroplasty. Histomorphometry software
was used to analyze computer images of 100-
μm-thick coronal and transverse plane sections of the
head and neck of the femur. Histologic preparations
of coronal and transverse sections of articular cartilage
Results—Bone volume/total volume, trabecular thickness,
trabecular number, and bone surface/total volume
were significantly higher in the femoral head
than femoral neck. Trabecular alignment (anisotropy)
and separation were significantly higher in the
femoral neck than femoral head. Anisotropy was significantly
increased in the medial portion of the
femoral head in the coronal plane and in the cranial
portion of the femoral neck in the transverse plane,
compared with healthy dogs. The medial half of
femoral head cartilage that overlies the proximomedial
cancellous bone region had significantly more
degraded cartilage than the lateral half. Histologic
grades for cranial and caudal halves of femoral head
articular cartilage were similar.
Conclusions and Clinical Relevance—Most findings
were similar to those in healthy dogs. Greater trabecular
alignment in the proximomedial region of the
femoral head and craniolateral region of the femoral
neck in dogs with osteoarthritis suggests an altered
transfer of load through the coxofemoral joint. Greater
cartilage degradation on the medial half of the femoral
head supports an association between increased trabecular
alignment and cartilage degradation. (Am J
Vet Res 2000;61:1267–1272)
OBJECTIVE To characterize the MRI and histologic features of the supraspinatus tendon in nonlame dogs.
ANIMALS 7 cadavers (14 shoulder joints) of nonlame 2-year-old sexually intact male Beagles.
PROCEDURES Multiple MRI fluid-sensitive pulse sequences were obtained for both shoulder joints of each cadaver, and the thickness, volume, and signal intensity of each supraspinatus tendon were assessed. After MRI scanning was complete, the shoulder joints were processed for histologic examination. Tissue specimens were stained with various stains to determine tendon morphology and composition. Histologic and MRI findings were correlated and described.
RESULTS All supraspinatus tendons had a trilaminar appearance on sagittal and transverse MRI images, which was characterized by a thick, hyperintense center layer (central substance) sandwiched between thin hypointense superficial and deep margins. The mean ± SD central substance-to-superficial margin and central substance-to-deep margin thickness ratios were 8.4 ± 1.2 and 9.0 ± 0.9, respectively; supraspinatus tendon-to-triceps brachii muscle signal intensity ratio was 1.3 ± 0.2; and tendon volume was 445 ± 20 mm3. The superficial and deep margins histologically resembled other tendons with highly ordered collagen fibers. The central substance was comprised of water-rich glycosaminoglycans interspersed among haphazardly arranged collagen bundles.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated histologically normal canine supraspinatus tendons have a trilaminar appearance on MRI images. In dogs, a diagnosis of supraspinatus tendinosis should not be based solely on the tendon having a hyperintense signal on MRI images; other MRI evidence of shoulder joint disease and diagnostic findings are necessary to support such a diagnosis.
Objective—To determine fibroblast viability, assess
development of apoptosis, and evaluate tissue hypoxia
via histochemical, in-situ hybridization, or immunohistochemical
staining in ruptured and intact cranial
cruciate ligaments (CCLs) of dogs.
Animals—32 dogs with ruptured CCLs, and 8 aged
and 19 young dogs with intact CCLs.
Procedure—Markers of cell viability (lactate dehydrogenase
[LDH]), apoptosis (terminal deoxynucleatidyl
transferase-mediated deoxyuridine triphosphate-nick
end labeling [TUNEL] method), and hypoxia (hypoxiainducible
factor-1α [HIF-1α] monoclonal antibody)
were applied to CCL specimens; positive cells were
assessed objectively (LDH) and subjectively (TUNEL
and HIF-1α) in the main axial tissue component (core)
and synovial intima and subintima (epiligamentous tissue).
Results—Viable fibroblasts were seen in all intact and
ruptured CCLs. More nonviable cells were found in
the core regions of ruptured CCLs and intact CCLs of
young dogs than in the epiligamentous regions.
Number of nonviable cells in the core region of ruptured
CCLs was greater than that in intact CCLs of
young and aged dogs, whereas the number in the
epiligamentous region was similar in all specimens.
The TUNEL and HIF-1αstaining was only found in the
epiligamentous region of ruptured CCLs.
Conclusions and Clinical Relevance—Ruptured
CCLs contained a high number of nonviable cells but
not a great number of apoptotic cells. Repair processes
in the epiligamentous region of the CCL include a
metabolic response to hypoxia, suggesting that
necrosis of ligament fibroblasts and transformation of
surviving cells to a spheroid phenotype may be a
response to hypoxia cause by microinjury or inadequate
blood flow. (Am J Vet Res 2003;64:1010–1016)
OBJECTIVE To identify risk factors associated with surgical site infection (SSI) in dogs following tibial plateau leveling osteotomy (TPLO).
DESIGN Retrospective cohort study.
ANIMALS 320 dogs that underwent unilateral or bilateral TPLO (n = 405 procedures) between 2007 and 2015 and were reexamined by a veterinarian at least once ≥ 8 weeks after the procedure.
PROCEDURES Data were extracted from medical records regarding signalment, TPLO procedure details, medical history of dermatitis, and SSI status. Logistic regression was performed to identify factors associated with SSI development.
RESULTS An SSI developed following 34 (8.4%; 95% confidence interval [CI], 6.1% to 11.5%) procedures. Prophylactic antimicrobial administration was provided following 36.8% (n = 149) of procedures. For 71 (17.5%) procedures, the dog had dermatitis at the time of surgery; 12 of these procedures involved dermatitis at the surgical site. The incidence of SSI following the 12 procedures for dogs with dermatitis at the surgical site was 16.7% (2/12 [95% CI, 3.3% to 54.3%]) and was 10.2% (6/59 [95% CI, 4.5% to 21.3%]) for dogs with dermatitis elsewhere; however, these differences in incidence were not significant. On multivariable analysis, German Shepherd Dogs (vs other breeds), meniscectomy (vs no meniscectomy), and attending surgeon having performed ≤ 20 (vs > 20) procedures during the study period were associated with increased odds of SSI.
CONCLUSIONS AND CLINICAL RELEVANCE SSI following TPLO was associated with the German Shepherd breed, meniscectomy, and surgeon. Prospective studies are needed to investigate the mechanisms underlying these associations.
Objective—To determine prevalence of the contralateral radiographic infrapatellar fat pad sign and contralateral radiographic degenerative sign (degenerative changes) and evaluate both signs as risk factors for subsequent contralateral cranial cruciate ligament (CrCL) rupture in dogs with unilateral CrCL rupture.
Design—Retrospective cohort study.
Animals—96 dogs with unilateral CrCL rupture and 22 dogs with bilateral CrCL rupture.
Procedures—Dogs with unilateral CrCL rupture were classified as having normal (n = 84) or abnormal (12) contralateral stifle joints on the basis of joint palpation. Associations between potential predictive variables and rates of subsequent contralateral CrCL rupture were evaluated.
Results—Of the 84 dogs with unilateral CrCL rupture in which the contralateral stifle joint was palpably normal, 29 (34.5%) had a contralateral fat pad sign and 31 (36.9%) had a degenerative sign. All dogs with unilateral CrCL rupture in which the contralateral stifle joint was palpably abnormal had a contralateral fat pad sign and degenerative sign. The contralateral fat pad sign was the most important risk factor for subsequent rupture of the contralateral CrCL. For dogs with unilateral CrCL rupture and palpably normal contralateral stifle joint with and without a contralateral fat pad sign, median time to subsequent rupture was 421 and 1,688 days, respectively, and the 3-year probability of subsequent rupture was 85.3% and 24.9%, respectively.
Conclusions and Clinical Relevance—Bilateral stifle joint radiography should be performed for all dogs with CrCL rupture. Bilateral stifle joint arthroscopy should be considered for dogs with a contralateral fat pad sign.