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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate the use of a combination of avocado and soybean unsaponifiable (ASU) extracts for the treatment of experimentally induced osteoarthritis in horses.

Animals—16 horses.

Procedures—Osteoarthritis was induced via osteochondral fragmentation in 1 middle carpal joint of each horse; the other joint underwent a sham operation. Horses were randomly allocated to receive oral treatment with ASU extracts (1:2 [avocado-to-soybean] ratio mixed in 6 mL of molasses; n = 8) or molasses (6 mL) alone (placebo treatment; 8) once daily from days 0 to 70. Lameness, response to joint flexion, synovial effusion, gross and histologic joint assessments, and serum and synovial fluid biochemical data were compared between treatment groups to identify effects of treatment.

Results—Osteochondral fragmentation induced significant increases in various variables indicative of joint pain and disease. Treatment with ASU extracts did not have an effect on signs of pain or lameness; however, there was a significant reduction in severity of articular cartilage erosion and synovial hemorrhage (assessed grossly) and significant increase in articular cartilage glycosaminoglycan synthesis, compared with placebo-treated horses.

Conclusions and Clinical Relevance—Although treatment with ASU extracts did not decrease clinical signs of pain in horses with experimentally induced osteoarthritis, there did appear to be a disease-modifying effect of treatment, compared with findings in placebotreated horses. These objective data support the use of ASU extracts as a disease-modifying treatment for management of osteoarthritis in horses.

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in American Journal of Veterinary Research

Abstract

Objective—To assess the clinical, biochemical, and histologic effects of intra-articular administration of autologous conditioned serum (ACS) in the treatment of experimentally induced osteoarthritis in horses.

Animals—16 horses.

Procedures—Osteoarthritis was induced arthroscopically in 1 middle carpal joint of all horses. In 8 placebo- and 8 ACS-treated horses, 6 mL of PBS solution or 6 mL of ACS was injected into the osteoarthritis-affected joint on days 14, 21, 28, and 35, respectively; PBS solution was administered in the other sham-operated joints. Evaluations included clinical assessment of lameness and synovial fluid analysis (performed biweekly); gross pathologic and histologic examinations of cartilage and synovial membrane samples were performed at necropsy.

Results—No adverse treatment-related events were detected. Horses that were treated with ACS had significant clinical improvement in lameness, unlike the placebo-treated horses. Among the osteoarthritis-affected joints, ACS treatment significantly decreased synovial membrane hyperplasia, compared with placebo-treated joints; although not significant, the ACS-treated joints also appeared to have less gross cartilage fibrillation and synovial membrane hemorrhage. The synovial fluid concentration of interleukin-1 receptor antagonist (assessed by use of mouse anti–interleukin-1 receptor antagonist antibody) was increased following treatment with ACS.

Conclusions and Clinical Relevance—Results of this controlled study indicated that there was significant clinical and histologic improvement in osteoarthritis-affected joints of horses following treatment with ACS, compared with placebo treatment. On the basis of these findings, further controlled clinical trials to assess this treatment are warranted, and investigation of the mechanisms of action of ACS should be pursued concurrently.

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in American Journal of Veterinary Research

Abstract

Objective—To determine effects of treadmill exercise on subchondral bone of carpal and metacarpophalangeal joints of 2-year-old horses.

Animals—12 healthy 2-year-old horses.

Procedure—Horses were randomly assigned to the control (n = 6) or exercised (6) groups. Horses in the exercised group ran on a high-speed treadmill 5 d/wk for 6 months. Horses in the control group were hand walked for the same amount of time. Results of clinical, radiographic, nuclear scintigraphic, and computed tomographic examinations, and serum and synovial concentrations of biochemical markers of bone metabolism were compared between groups.

Results—Exercised horses were significantly lamer at the end of the study than control horses. Radionuclide uptake in the metacarpal condyles, but not in the carpal joints, was greater in exercised horses, compared with control horses. Exercised horses also had a higher subchondral bone density in the metacarpal condyles than control horses, but such differences were not detected in the carpal bones.

Conclusions and Clinical Relevance—None of the diagnostic techniques evaluated was sufficiently sensitive to detect all osteochondral damage. Computed tomography and computed tomographic osteoabsorptiometry were superior to conventional radiography for detecting small osteochondral fragments. Nuclear scintigraphy was a sensitive indicator of subchondral bone change but lacked specificity for describing lesions and discerning normal bone remodeling from damage. Newer techniques such as computed tomography may help clinicians better diagnose early and subtle joint lesions in horses prior to development of gross joint damage. (Am J Vet Res 2000;61:1252–1258)

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate whether cutting equine subchondral bone to demarcate specific regions of interest (ROIs) influences the mean density for that bone as measured via quantitative computed tomography (QCT).

Sample population—2 metacarpophalangeal joints from equine cadavers.

Procedures—The distal portion of the third metacarpal bone of each intact metacarpophalangeal joint was scanned via CT to simulate in vivo conditions. Each joint was subsequently disarticulated and dissected, and the distal portion of the dissected third metacarpal bone in air was scanned. Then, six 1-cm2 areas representing ROIs were cut into the distal condylar surfaces to depths of approximately 1 cm, and the bone was scanned again. Three-dimensional CT models of the 3 bone preparations were generated for each third metacarpal bone on the basis of data from each set of scan images, and densities of the 6 ROIs were measured. Mean bone densities for the 6 ROIs were compared among models of intact, dissected, and cut third metacarpal bone scans.

Results—Mean bone density was significantly lower in cut bone preparations, compared with that in intact or dissected bone. Differences between mean bone densities for intact and dissected bone preparations were not significant.

Conclusions and Clinical Relevance—Cutting subchondral bone to demarcate specific ROIs prior to CT imaging significantly lowered mean bone density as measured via QCT and thus introduced substantial artifacts. These findings have direct implications on techniques for CT modeling of equine subchondral bone in the characterization of joint diseases in horses.

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in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To investigate potential associations between repository radiographic findings and subsequent performance of Quarter Horses competing in cutting events.

DESIGN Retrospective cohort study.

SAMPLE Repository radiographs (ie, radiographs obtained at the time of sale) for 343 client-owned horses.

PROCEDURES Repository radiographic findings were compared with objective measures of performance, including the likelihood of competing; the likelihood of earning money as a 3-year-old, as a 4-year-old, and as a 3- and 4-year-old combined; and the amount of money earned as a 3-year-old, as a 4-year-old, and as a 3- and 4-year-old combined.

RESULTS The presence of mild osteophytes involving the distal aspect of the tarsal joint was significantly associated with lower mean earnings as a 4-year-old. The presence of osteophytes on the dorsoproximal aspect of the middle phalanx of the hind limbs was significantly associated with an increased odds of earning money as a 4-year-old. Radiographic lesions of the medial femoral condyle of the stifle joint were not significantly associated with subsequent performance.

CONCLUSIONS AND CLINICAL RELEVANCE Most abnormalities identified on repository radiographs were not significantly associated with subsequent performance. The significant association between mild tarsal osteophytosis and earnings was unexpected. Results of the present study indicated the need for further investigation of the relationship between radiographic findings and performance outcome in Western performance horses.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify risk factors for development of excessive tibial plateau angle (TPA) in large-breed dogs with cranial cruciate ligament disease (CCLD).

Design—Case-control study.

Animals—58 dogs with excessive TPAs (ie, TPA ≥ 35°; case dogs) and 58 dogs with normal TPAs (ie, TPA ≤ 30°; control dogs).

Procedures—Medical records and radiographs were reviewed and owners were interviewed to identify potential risk factors for excessive TPA.

Results—Case dogs were 3 times (95% confidence interval, 1.2 to 8.0) as likely to have been neutered before 6 months of age as were control dogs. Case dogs with TPA ≥ 35° in both limbs were 13.6 times (95% confidence interval, 2.72 to 68.1) as likely to have been neutered before 6 months of age as were control dogs with TPA ≤ 30° in both limbs. Case dogs were significantly younger at the onset of hind limb lameness than were control dogs.

Conclusions and Clinical Relevance—Results suggested that early neutering was a significant risk factor for development of excessive TPA in large-breed dogs with CCLD. Further research into the effects of early neutering on TPA and the pathophysiology of CCLD is warranted.

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in Journal of the American Veterinary Medical Association