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  • Author or Editor: P. R. van Weeren x
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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 histologic sections.

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: 210–219)

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in American Journal of Veterinary Research


Objective—To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses.

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 osteochondrosis lesions.

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)

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in American Journal of Veterinary Research


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 osteoarthritis.

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 2005;66:1238–1246)

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in American Journal of Veterinary Research



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.

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in Journal of the American Veterinary Medical Association