Objective—To correlate quantitative analysis of ultrasonographic
images of normal (injury-free) equine
superficial digital flexor (SDF) tendons and equine
SFD tendons that have pathologic changes with corresponding
Sample Population—4 SDF tendons, 2 of which
had various stages of tissue integrity. The 2 ipsilateral
tendons were used as points of reference.
Procedure—Tendons were mounted in a custommade
device that permitted sequential scanning,
transversely and perpendicular to the tendon long
axis. At precise steps of 0.5 mm, transverse ultrasonographic
images were collected. Subsequently,
tendons were fixed and prepared for histologic
examination. The following 8 tissue types were
discerned: normal young, normal old, necrotic,
early granulation, late granulation, early fibrotic,
late fibrotic, and scar tissues. In areas of interest,
the corresponding ultrasonographic images were
selected for gray level statistical analysis.
Results—Compared with other tissue types, earlystage
granulation tissue was characterized by substantially
lower mean gray level and a clearly different
histogram. Necrotic tissue had a higher mean
gray level, with a virtually normal histogram. In late
granulation and early fibrotic tissues, the mean gray
level and the histogram could not be discerned
from those of normal tendon tissue. The same
applied to late fibrotic and scar tissues; mean gray
levels were fractionally lower than those of normal
tendon tissue with a completely normal histogram.
Conclusions—Although quantification of the transverse
ultrasonographic image by use of first-order
gray level statistics may be helpful, the method is
not sufficiently sensitive to accurately and unequivocally
determine the type of tendon tissue.
Quantitative analysis should incorporate transverse
and longitudinal information. (Am J Vet Res 2000;61:
Objective—To determine whether serum concentrations
of biomarkers of skeletal metabolism can,
in conjunction with radiographic evaluation, indicate
severity of osteochondrosis in developing
Animals—43 Dutch Warmblood foals with varying
severity of osteochondrosis.
Procedure—24 foals were monitored for 5 months
and 19 foals were monitored for 11 months. Monthly
radiographs of femoropatellar-femorotibial and tibiotarsal
joints were graded for osteochondral abnormalities.
Serial blood samples were assayed for 8 cartilage
and bone biomarkers. At the end of the monitoring
period, foals were examined for macroscopic
Results—Temporal relationships were evident
between certain serum biomarkers and osteochondrosis
severity in foals during their first year.
Biomarkers of collagen degradation (collagenasegenerated
neoepitopes of type-II collagen fragments,
type-I and -II collagen fragments [COL2-3/4Cshort],
and cross-linked telopeptide fragments
of type-I collagen) and bone mineralization (osteocalcin)
were positive indicators of osteochondrosis
severity at 5 months of age. In foals with lesions at
11 months of age, osteochondrosis severity correlated
negatively with COL2-3/4Cshort and osteocalcin
and positively with C-propeptide of type-II procollagen
(CPII), a collagen synthesis marker.
Radiographic grading of osteochondrosis lesions
significantly correlated with macroscopic osteochondrosis
severity score at both ages and was
strongest when combined with osteocalcin at 5
months and CPII at 11 months.
Conclusions and Clinical Relevance—The ability of
serum biomarkers to indicate osteochondrosis severity
appears to depend on stage of disease and is
strengthened with radiography. In older foals with
more permanent lesions, osteochondrosis severity is
significantly related to biomarker concentrations of
decreased bone formation and increased cartilage synthesis.
(Am J Vet Res 2004;65:143–150)
Objective—To assess whether site-related changes
in biochemical composition are present in the cartilage
and subchondral and trabecular bone of the
metacarpophalangeal joint of horses with early
Sample Population—Right metacarpophalangeal
joints from 59 mature warmblood horses.
Procedure—Biochemical data (cross-link, amino acid,
DNA, and ash contents; denatured collagen and glycosaminoglycan
[GAG] concentrations; bone mineral
density; and mineral composition) were obtained
from 2 differently loaded sites of phalanx I cartilage
and subchondral and trabecular bone samples; data
were compared with previously published values
from nonosteoarthritic equine joints.
Results—Compared with findings in nonosteoarthritic
joints, GAG concentration was lower in cartilage from
osteoarthritic joints and there was a loss of site differences
in cellularity and lysylpyridinoline (LP) cross-link
content. In subchondral bone, LP cross-link content was
decreased overall and there was a loss of site differences
in osteoarthritic joints; ash content was higher in
the osteoarthritic joints. Hydroxyproline content in trabecular
bone from osteoarthritic joints was greater than
that in nonosteoarthritic trabecular bone. In all 3 layers
and at both sites, the linear increase of the pentosidine
cross-link content with age had diminished or was not
apparent in the horses with osteoarthritic joints.
Conclusions and Clinical Relevance—In equine
metacarpophalangeal joints with early osteoarthritis,
distinct biochemical changes were detected in the
cartilage and subchondral and trabecular bone. The
dissimilarity in response of the different tissues and
differences between the sites that are affected may
be related to differences in biomechanical loading and
transmission and dissipation of force. (Am J Vet Res
To verify the existence of intertransverse joints (ITJs) in young foals.
11 warmblood foals.
Postmortem examination of the lumbar area in foals < 200 days old using CT, MRI, dissection, and histomorphology. Data were analyzed with descriptive statistics.
Age of foals varied between 1 and 200 days (median, 11 days). Ten foals had 6 lumbar (L) vertebrae, and 1 foal had 5. All 11 foals, irrespective of age, had ITJs between the first sacral and last lumbar vertebrae and between the last and second-to-last lumbar vertebrae. In 6 foals (all with 6 L vertebrae), ITJs also existed between the fourth and fifth L vertebra. One foal, also with 6 L vertebrae, additionally had a unilateral (right) ITJ between the transverse processes of the third and fourth L vertebra. Based on CT, width of ITJs was seemingly greater in young (< 1 month old) foals because of the incomplete ossification of the transverse processes. The ITJs were confirmed and further characterized by MRI, dissection, and histomorphology.
ITJs already exist in very young warmblood foals and are present at birth. During the first months of life, these juvenile ITJs develop similarly to other synovial joints with increasing ossification and concomitant decrease of thickness of the cartilage layer. Knowledge of the presence of these ITJs in young animals is clinically relevant, as they should be recognized as nonpathologic when for instance a young foal is presented for presumed arthropathy and examined with advanced imaging techniques.