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  • Author or Editor: C. Wayne McIlwraith x
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Abstract

Objective—To determine the outcome of horses with basal fractures of the proximal sesamoid bone from which a fracture fragment involving a portion of the base of the bone was removed arthroscopically and to determine whether fragment size was associated with outcome.

Design—Retrospective study.

Animals—26 horses.

Procedure—Dorsopalmar and axial-abaxial lengths of the fracture fragment were measured on the dorsopalmar and mediolateral radiographic views, respectively, and percentage of the base of the sesamoid bone involved was estimated. Fractures were classified as grade 1 (≤ 25% of the base involved) or grade 2 (> 25% but < 100% of the base involved). Outcome was classified as successful if the horse started at least 2 races or unsuccessful if the horse started only 1 race or failed to return to racing.

Results—There were 24 racehorses and 2 nonracehorses. Twelve (50%) of the racehorses returned to racing and started at least 2 races. Eight of 14 horses with grade-1 fractures and 4 of 10 horses with grade- 2 fractures had a successful outcome. Ten of 16 horses without associated articular disease had successful outcomes, compared with 2 of 8 horses with associated articular disease. However, fragment size and presence of associated articular disease were not significantly associated with outcome.

Conclusions and Clinical Relevance—Horses with basal fractures of the proximal sesamoid bone from which a fracture fragment involving a portion of the base of the bone is removed arthroscopically have a fair prognosis for return to racing. (J Am Vet Med Assoc 2000;217:236–240)

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in Journal of the American Veterinary Medical Association

Abstract

Objectives—To evaluate the effects of equine recombinant interleukin-1α (rEqIL-1α) and recombinant interleukin- 1β (rEqIL-1β) on proteoglycan metabolism and prostaglandin E2 (PGE2) synthesis by equine articular chondrocytes in explant culture.

Sample Population—Near full-thickness articular cartilage explants (approx 50 mg) harvested from stifle joints of a 3-year-old and a 5-year-old horse.

Procedure—Expression constructs containing cDNA sequences encoding EqIL-1α and EqIL-1β were generated, prokaryotically expressed, and the recombinant protein purified. Near full-thickness articular cartilage explants (approx 50 mg) harvested from stifle joints of a 3-year-old and a 5-year-old horse were separately randomized to receive rEqIL- 1α or rEqIL-1β treatments (0 to 500 ng/ml). Proteoglycan release was evaluated by 1,9-dimethylmethylene blue spectrophotometric analysis of explant media glycosaminoglycan (GAG) concentration and release of 35S-sulfate-labeled GAG to explant media. Proteoglycan synthesis was assessed by quantification of 35S-sulfate incorporation into proteoglycan. Explant media PGE2 concentrations were evaluated using a PGE2-specific enzyme-linked immunoassay. Data were collected at 48-hour intervals and normalized by DNA content.

Results—Proteoglycan release was induced by rEqIL- 1α and rEqIL-1β at concentrations ≥ 0.1 ng/ml, with 38 to 76% and 88 to 98% of total GAG released by 4 and 6 days, respectively. Inhibition of proteoglycan synthesis (42 to 64%) was observed at IL-1 concentrations ≥ 0.1 ng/ml at 2 and 4 days. Increased PGE2 concentrations were observed at IL-1 concentrations ≥ 0.1 ng/ml at 2 and 4 days.

Conclusions and Clinical Relevance—The rEqIL-1 induced potent concentration-dependent derangement of equine chondrocyte metabolism in vitro . These findings suggest this model may be suitable for the in vitro study of the pathogenesis and treatment of joint disease in horses. (Am J Vet Res 2002; 63:551–558)

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in American Journal of Veterinary Research

Abstract

Objective—To assess the clinical, biochemical, and histologic effects of extracorporeal shock wave therapy (ESWT) in the treatment of horses with experimentally induced osteoarthritis (OA).

Animals—Twenty-four 2- to 3-year-old horses without evidence of lameness.

Procedures—OA was induced arthroscopically in 1 middle carpal joint of each horse. Fourteen days after induction of OA, horses were treated with a sham ESWT probe (placebo; n = 8), polysulfated glycosaminoglycan (PSGAG) administered IM every 4 days for 28 days as a positive control treatment (8), or ESWT administered on days 14 and 28 with a focused shock wave unit (8). Evaluations included clinical assessments of degree of lameness every 2 weeks and weekly synovial fluid analyses. Horses were euthanized 70 days after induction of OA, and gross pathologic and histologic examinations of cartilage and synovial membrane specimens were performed at necropsy. A generalized linear mixed model was used to compare outcomes among treatment groups.

Results—No adverse treatment-related events were detected in any horse. The degree of lameness in horses treated with ESWT improved significantly, compared with the degree of lameness in placebo- or PSGAG-treated horses. No disease-modifying effects were evident in results for synovial fluid, synovial membranes, or cartilage from the ESWT- or PSGAG-treated horses.

Conclusions and Clinical Relevance—Although a disease-modifying effect of ESWT was not detected, the significant clinical effect of ESWT suggested that this modality should be considered for treatment of horses with OA in combination with another modality that does affect the disease process.

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate effects of extracorporeal shock wave therapy (ESWT) and polysulfated glycosaminoglycan treatment (PSGAGT) on subchondral bone (SCB), serum biomarkers, and synovial fluid biomarkers in horses with induced osteoarthritis.

Animals—24 healthy 2- to 3-year-old horses.

Procedures—An osteochondral fragment was created on the distal aspect of the radial carpal bone in 1 middle carpal joint of each horse. Horses were randomly allocated to receive local application of ESWT (days 14 and 28; n = 8), PSGAGT (IM, q 4 d for 28 days; 8), or a sham ESWT probe (placebo; days 14 and 28; 8). Serum biomarkers were measured every 7 days, and synovial fluid biomarkers were measured every 14 days. Bone density was measured by use of computed tomography on days 0 and 70, and microdamage and bone formation variables were compared among groups at the end of the study (day 70).

Results—There was no significant effect of ESWT or PSGAGT on any bone variable. Serum osteocalcin concentration was significantly greater in horses that received ESWT, compared with placebo-treated horses, and serum concentration of the C-terminal telopeptide of type I collagen was significantly higher in horses that received ESWT, compared with placebo- and PSGAG-treated horses. Concentrations of the synovial fluid epitope CS846 were significantly higher in joints with osteoarthritis treated with ESWT

Conclusions and Clinical Relevance—Treatment of osteoarthritis with ESWT had no effect on SCB but did induce increases in serum biomarkers indicative of bone remodeling. Treatment of osteoarthritis with PSGAG had no effect on SCB or biomarkers.

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in American Journal of Veterinary Research

Abstract

Objective—To assess clinical, radiographic, histologic, and biochemical effects of sodium pentosan polysulfate (NaPPS) administered IM for treatment of experimentally induced osteoarthritis in horses.

Animals—18 horses.

Procedures—Osteoarthritis was induced arthroscopically in 1 middle carpal joint of all horses. Nine horses received NaPPS (3 mg/kg, IM) on study days 15, 22, 29, and 36. Nine control horses received the same volume of saline (0.9% NaCl) solution IM on study days 15, 22, 29, and 36. Clinical, radiographic, gross, histologic, histochemical, and biochemical findings as well as findings of synovial fluid analysis were evaluated.

Results—No adverse treatment-related events were detected. Induced osteoarthritis caused a substantial increase in lameness, response to flexion, joint effusion, radiographic findings, synovial membrane inflammation, and articular cartilage fibrillation. Articular cartilage fibrillation was substantially reduced by NaPPS treatment, and concentrations of chondroitin sulfate 846 epitope were significantly increased in the synovial fluid of osteoarthritic and nonosteoarthritic joints of treated horses.

Conclusions and Clinical Relevance—Results indicated that NaPPS has some beneficial disease-modifying effects and may be a therapeutic option for osteoarthritis in horses.

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate the temporal pattern of prostaglandin (PG) E2 concentrations in synovial fluid after transection of the cranial cruciate ligament (CCL) in dogs and to correlate PGE2 concentrations with ground reaction forces and subjective clinical variables for lameness or pain.

Animals—19 purpose-bred adult male Walker Hounds.

Procedure—Force plate measurements, subjective clinical analysis of pain or lameness, and samples of synovial fluid were obtained before (baseline) and at various time points after arthroscopic transection of the right CCL. Concentrations of PGE2 were measured in synovial fluid samples, and the PGE2 concentrations were correlated with ground reaction forces and clinical variables.

Results—The PGE2 concentration increased significantly above the baseline value throughout the entire study, peaking 14 days after transection. Peak vertical force and vertical impulse significantly decreased by day 14 after transection, followed by an increase over time without returning to baseline values. All clinical variables (eg, lameness, degree of weight bearing, joint extension, cumulative pain score, effusion score, and total protein content of synovial fluid, except for WBC count in synovial fluid) increased significantly above baseline values. Significant negative correlations were detected between PGE2 concentrations and peak vertical force (r, –0.5720) and vertical impulse (r, –0.4618), and significant positive correlations were detected between PGE2 concentrations and the subjective lameness score (r, 0.5016) and effusion score (r, 0.6817).

Conclusions and Clinical Relevance—Assessment of the acute inflammatory process by measurement of PGE2 concentrations in synovial fluid may be correlated with the amount of pain or lameness in dogs. (Am J Vet Res 2004;65:1269–1275)

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in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of exercise at an early age on tissues in the metacarpophalangeal joints of horses.

Animals—Twelve 18-month-old horses.

Procedures—All horses were pasture reared, but 6 horses had additional exercise starting at 3 weeks of age until 18 months of age. At that time, computed tomography, articular cartilage metabolism evaluation, and histologic assessments of synovial membrane, articular cartilage, and subchondral bone were performed.

Results—Exercised horses had fewer gross lesions, less articular cartilage matrix staining in the dorsal aspect of the condyle, greater bone fraction in the dorsolateral aspect of the condyle, and higher bone formation rate, compared with nonexercised horses.

Conclusions and Clinical Relevance—Exercise at a young age may be protective to joints, although more research is needed to characterize changes in articular cartilage matrix. Results suggested that exercise can be safely imposed at an early age.

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in American Journal of Veterinary Research

Abstract

Objective—To determine response of interleukin-1α (IL-1α)-conditioned equine articular cartilage explants to insulin-like growth factor-1 (IGF-1).

Sample Population—Cartilage from the trochlea and condyles of the femur of a clinically normal 4-year-old horse.

Procedure—Effects of IGF-1 (0 to 500 ng/ml) after addition of IL-1α were evaluated by assessing matrix responses, using a sulfated glycosaminoglycan (GAG) assay, matrix 35SO4 GAG incorporation, and release of GAG. Mitogenic response was assessed by 3H-thymidine incorporation into DNA and fluorometric assay of total DNA concentration.

Results—Human recombinant IL-1α (40 ng/ml) increased the amount of labeled GAG released and decreased labeled and total GAG remaining in explants, and IL-1α decreased mitogenic response. Addition of IGF-1 counteracted effects seen with IL-1α alone. In general, IGF-1 decreased total and labeled GAG released into the medium, compared with IL-1α- treated explants (positive-control sample). Values for these variables did not differ significantly from those for negative-control explants. A significant increase in total and newly synthesized GAG in the explants at termination of the experiment was observed with 500 ng of IGF-1/ml. Labeled GAG remaining in explants was greater with treatment at 50 ng of IGF-1/ml, compared with treatment with IL-1α alone. Concentrations of 200 ng of IGF-1/ml abolished actions of IL-1α and restored DNA synthesis to values similar to those of negative-control explants.

Conclusions and Clinical Relevance—IGF-1 at 500 ng/ml was best at overcoming detrimental effects associated with IL-1α in in vitro explants. These beneficial effects may be useful in horses with osteoarthritis. (Am J Vet Res 2000;61:436–441)

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in American Journal of Veterinary Research

Abstract

Objective—To compare the mesenchymal stem cell (MSC) yield and chondrogenic and osteogenic differentiation from 5- and 50-mL bone marrow aspirates from horses.

Animals—Six 2- to 5-year-old mixed-breed horses.

Procedures—2 sequential 5-mL aspirates were drawn from 1 ilium or sternebra. A single 50-mL aspirate was drawn from the contralateral ilium, and 2 sequential 50-mL aspirates were drawn from a second sternebra. The MSC yield was determined through the culture expansion process. Chondrogenesis and osteogenesis were evaluated by means of conventional laboratory methods.

Results—The second of the 2 sequential 50-mL sternal aspirates yielded few to no MSCs. Independent of location, the highest density of MSCs was in the first of the 2 sequential 5-mL fractions, although with subsequent culture expansion, the overall yield was not significantly different between the first 5-mL and first 50-mL fractions. Independent of location, chondrogenesis and osteogenesis were not significantly different among fractions. Independent of fraction, the overall cell yield and chondrogenesis from the ilium were significantly higher than that from the sternum.

Conclusions and Clinical Relevance—This study failed to detect an additional benefit of 50-mL aspirates over 5-mL aspirates for culture-expanding MSCs for equine clinical applications. Chondrogenesis was highest for MSCs from ilial aspirates, although it is not known whether chondrogenesis is indicative of activation of other proposed pathways by which MSCs heal tissues.

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether decreases in peak vertical force of the hind limb after transection of the cranial cruciate ligament (CrCL) would be indicative of medial meniscal damage in dogs.

Animals—39 purpose-bred adult male Walker Hounds.

Procedure—The right CrCL was transected arthroscopically. Force plate measurements of the right hind limb were made prior to and 2, 4, 10, and 18 weeks after transection of the CrCL. Only dogs with ≥ 10% decreases in peak vertical force after week 2 were considered to have potential meniscal damage. Dogs that did not have ≥ 10% decreases in peak vertical force at any time point after week 2 were assigned to group 1. Group 2 dogs had ≥ 10% decreases in peak vertical force from weeks 2 to 4 only. Group 3 and 4 dogs had ≥ 10% decreases in peak vertical force from weeks 4 to 10 only or from weeks 10 to 18 only, respectively. Damage to menisci and articular cartilage was graded at week 18, and grades for groups 2 to 4 were compared with those of group 1.

Results—The percentage change in peak vertical force and impulse area was significantly different in groups 2 (n = 4), 3 (4), and 4 (4) at the end of each measurement period (weeks 4, 10, and 18, respectively) than in group 1 (27). The meniscal grade for groups 2 to 4 was significantly higher than for group 1. A ≥ 10% decrease in peak vertical force had sensitivity of 52% and accuracy of 72% for identifying dogs with moderate to severe medial meniscal damage.

Conclusions and Clinical Relevance—In dogs with transected or ruptured CrCLs, force plate analysis can detect acute exacerbation of lameness, which may be the result of secondary meniscal damage, and provide an objective noninvasive technique that delineates the temporal pattern of medial meniscal injury. ( Am J Vet Res 2005;66:156–163)

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in American Journal of Veterinary Research