Natasha M. Werpy

Evaluation of polysulfated glycosaminoglycan or sodium hyaluronan administered intra-articularly for treatment of horses with experimentally induced osteoarthritis

OBJECTIVE To assess clinical, biochemical, and histologic effects of polysulfated glycosaminoglycan (PSGAG) or sodium hyaluronan administered intra-articularly in treatment of horses with experimentally induced osteoarthritis. ANIMALS 24 horses. PROCEDURES Osteoarthritis was induced arthroscopically in 1 middle carpal joint of all horses. Eight horses received hyaluronan (20 mg) and amikacin (125 mg) intra-articularly on study days 14, 21, and 28. Eight horses received PSGAG (250 mg) and amikacin (125 mg) intra-articularly on study days 14, 21, and 28. Eight control horses received 2 mL of saline (0.9% NaCl) solution and amikacin (125 mg) intra-articularly on study days 14, 21, and 28. Clinical, radiographic, synovial fluid analysis, gross, histologic, histochemical, and biochemical findings were evaluated. RESULTS No adverse treatment-related events were detected. Induced osteoarthritis caused a substantial change in lameness, response to flexion, joint effusion, and radiographic findings, and of these, synovial fluid effusion was reduced with PSGAG, compared with control horses. No changes in clinical signs were seen with PSGAG or hyaluronan, compared with control horses. Histologically, the degree of synovial membrane vascularity and subintimal fibrosis was significantly reduced with PSGAG treatment, compared with controls. Histologically, significantly less fibrillation was seen with hyaluronan treatment, compared with controls. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that PSGAG and hyaluronan had beneficial disease-modifying effects and are viable therapeutic options for osteoarthritis in horses.

Evaluation of topically administered diclofenac liposomal cream for treatment of horses with experimentally induced osteoarthritis

OBJECTIVE To assess the clinical, biochemical, and histologic effects of topically administered diclofenac liposomal cream (DLC) in the treatment of horses with experimentally induced osteoarthritis. ANIMALS 24 horses. PROCEDURES Osteoarthritis was induced arthroscopically in 1 middle carpal joint of all horses. Eight horses treated with DLC were given 7.3 g twice daily via topical application. Eight horses treated with phenylbutazone were given 2 g orally once daily. Eight control horses received no treatment. Evaluations included clinical, radiographic, magnetic resonance imaging, synovial fluid, gross, and histologic examinations as well as histochemical and biochemical analyses. RESULTS No adverse treatment-related events were detected. Horses that were treated with DLC or phenylbutazone had significant clinical improvement of lameness, unlike the control horses. Treatment with DLC induced significant improvement in staining and total articular glycosaminoglycan content, compared with no treatment. Treatment with phenylbutazone induced significant reduction in synovial fluid prostaglandin E2 concentration, compared with DLC and no treatment. Treatment with DLC induced significantly less radial carpal bone sclerosis and overall gross cartilage erosion, compared with phenylbutazone. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that DLC had both clinical sign-modifying and disease-modifying effects. Only clinical sign-modifying effects were detected in association with phenylbutazone administration. Treatment with DLC had significant beneficial effects, compared with phenylbutazone, and no detrimental effects. Results suggested that DLC is a viable therapeutic option for horses with osteoarthritis.

Outcomes of podotrochlear (navicular) bursa injections for signs of foot pain in horses evaluated via magnetic resonance imaging: 23 cases (2005-2007).

OBJECTIVE To determine clinical outcome following intrathecal injection of the podotrochlear (navicular) bursa for signs of foot pain in horses evaluated via magnetic resonance imaging (MRI) and evaluate efficacy of corticosteroids administered with or without hyaluronate. DESIGN Retrospective case series. ANIMALS 23 horses. PROCEDURES Data collected included signalment, history, intended use, duration and severity of lameness, results of diagnostic anesthesia, radiographic abnormalities, MRI abnormalities, and outcomes for return to use. RESULTS MRI was conducted on 23 horses with lameness localized to the foot. Thirteen horses had bilateral forelimb lameness, and 10 had unilateral forelimb lameness. Mean duration of lameness was 10.5 months. Seventeen of 23 (74%) horses had excellent outcomes and returned to intended use within 2 to 4 weeks after navicular bursa injection. Hyaluronate treatment was not associated with outcome; however, horses receiving < 10 mg of trimacinolone had significantly worse outcomes than those treated with hyaluronate. Among horses with excellent outcomes, mean duration of soundness was 7.3 months. Seven of 8 horses with erosive lesions of the flexor surface of the distal sesamoid (navicular) bone diagnosed via MRI had a poor outcome. Horses with navicular bursitis responded optimally to injection, compared with horses with other problems. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that intrathecal injection of corticosteroid in horses with erosions of the flexor surface of the navicular bone associated with deep digital flexor tendon adhesions yielded a poor response. Treatment of horses with navicular bursitis via injection of the navicular bursa should be highly effective in alleviating lameness.

COMPARISON BETWEEN STANDARD ULTRASONOGRAPHY, ANGLE CONTRAST ULTRASONOGRAPHY, AND MAGNETIC RESONANCE IMAGING CHARACTERISTICS OF THE NORMAL EQUINE PROXIMAL SUSPENSORY LIGAMENT

Previous studies have proposed that standard ultrasonography may not adequately represent the pertinent anatomic characteristics of the equine proximal suspensory ligament. The purpose of the study was to compare the use of standard ultrasonography, angle contrast ultrasonography, MRI, and histology for identification of the anatomic characteristics of the normal equine suspensory ligament in the forelimb. Horses free from forelimb lameness with no palpable abnormalities in the region of the suspensory ligament were included in the study. The proximal suspensory ligaments in 20 forelimbs were examined using the standard ultrasound technique, angle contrast ultrasound technique, and MRI, followed by histologic evaluation. Total transverse (cross-sectional) area of the proximal suspensory ligament was estimated using the standard ultrasound and the angle contrast ultrasound techniques, MRI, and histologic sections for the following parameters: total area of the ligament, ligament fibers, muscle, and fat. The proximal suspensory ligament lobe size and tissue distribution were compared and subjectively graded (0-4) for asymmetry. Subjectively, angle contrast ultrasound technique improved differentiation of fibers from the remaining tissue types and allowed identification of the peripheral ligament margin. There was no significant difference in asymmetry scores between modalities. The asymmetry scores of the right and left forelimbs were significantly different with both ultrasound and MRI, based on the level of measurement. The angle contrast ultrasound technique has limitations compared to MRI. However, it provides additional diagnostic information that is not available with the standard ultrasound technique.

Evaluation of intra-articular hyaluronan, sodium chondroitin sulfate and N-acetyl-D-glucosamine combination versus saline (0.9% NaCl) for osteoarthritis using an equine model.

A randomized blinded placebo controlled trial was conducted to assess the clinical, biochemical and histological effects of a hyaluronan, sodium chondroitin sulfate and N-acetyl-D-glucosamine combination (PG) administered through an intra-articular (IA) route for the treatment of osteoarthritis (OA) at the time of injury. OA was induced in one carpal joint of each of 16 horses. Horses were designated placebo or IA PG treated. All horses were treated with 125 mg amikacin sulfate IA and 5 mL physiological saline in the middle carpal joint bilaterally on study Days 0 (after induction of OA), 7, 14 and 28, except the OA affected joint of the IA PG horses, which received 5 mL PG plus 125 mg of amikacin sulfate on similar days. Evaluations included clinical and radiographic, synovial fluid analysis, gross and histological examinations, as well as histochemical and biochemical analyses. The model induced a significant pathology that resulted in clinical disease. No adverse treatment-related events were detected in any of the horses. Intra-articular treatment of OA-affected joints with PG resulted in a transient 16% improvement in clinical pain (lameness scores) and evidence of improvement trends in bone proliferation radiographically as well as in the degree of full thickness articular cartilage erosion seen grossly when compared to placebo treated OA affected joints, although the vast majority of outcome parameters were not significantly different than controls. The findings support some potential clinical sign or disease modifying action of this compound administered IA at the tested dose and frequency.

Imaging of the Equine Proximal Suspensory Ligament

Injury to the suspensory ligament can result in significant lameness. Multiple imaging modalities may be required to fully characterize injury to the suspensory ligament. Ultrasonography of the suspensory ligament is challenging, due to the normal anatomy. This article describes imaging of the proximal suspensory ligament in the front and hind limbs of the horse.

Effects of the Combination of Microfracture and Self-Assembling Peptide Filling on the Repair of a Clinically Relevant Trochlear Defect in an Equine Model

BACKGROUND The goal of this study was to test the ability of an injectable self-assembling peptide (KLD) hydrogel, with or without microfracture, to augment articular cartilage defect repair in an equine cartilage defect model involving strenuous exercise. METHODS Defects 15 mm in diameter were created on the medial trochlear ridge and debrided down to the subchondral bone. Four treatment groups (n = 8 each) were tested: no treatment (empty defect), only defect filling with KLD, only microfracture, and microfracture followed by filling with KLD. Horses were given strenuous exercise throughout the one-year study. Evaluations included lameness, arthroscopy, radiography, and gross, histologic, immunohistochemical, biochemical, and biomechanical analyses. RESULTS Overall, KLD-only treatment of defects provided improvement in clinical symptoms and improved filling compared with no treatment, and KLD-only treatment protected against radiographic changes compared with microfracture treatment. Defect treatment with only microfracture also resulted in improved clinical symptoms compared with no treatment, and microfracture treatment resulted in repair tissue containing greater amounts of aggrecan and type-II collagen compared with KLD-only treatment. Microfracture treatment also protected against synovial fibrosis compared with no treatment and KLD-only treatment. Treatment with the self-assembling KLD peptide in combination with microfracture resulted in no additional improvements over microfracture-only treatment. In general, the nature of the predominant tissue in the defects was a mix of noncartilaginous and fibrocartilage tissue, with no significant differences among the treatments. CONCLUSIONS Treatment of defects with only KLD or with only microfracture resulted in an improvement in clinical symptoms compared with no treatment; the improvement likely resulted from different causes depending on the treatment. Whereas microfracture improved the quality of repair tissue, KLD improved the amount of filling and protected against radiographic changes. CLINICAL RELEVANCE Treatment of defects with only microfracture and with KLD only resulted in clinical improvements compared with untreated defects, despite differing with respect to the structural improvements that they induced.

COMPARISON BETWEEN COMPUTED TOMOGRAPHIC ARTHROGRAPHY, RADIOGRAPHY, ULTRASONOGRAPHY, AND ARTHROSCOPY FOR THE DIAGNOSIS OF FEMOROTIBIAL JOINT DISEASE IN WESTERN PERFORMANCE HORSES

The femorotibial joints are a common source of lameness in Western performance horses. The objective of this prospective study was to compare the radiography, ultrasonography, computed tomographic arthrography (CTA), and arthroscopy findings in horses with lameness localized to the femorotibial joints. Twenty-five stifles in 24 horses were included and were evaluated with all four of these diagnostic methods. Defects detected in femorotibial joint structures were compared between diagnostic methods using a McNemars test to evaluate for disagreement. Cranial medial meniscotibial desmopathy was most detected on arthroscopy (in 14/25 cases) and was only detected on ultrasonography in three out of 11 (27.3%) arthroscopically observed cases, but was detected on CTA in nine out of 12 (75%) arthroscopically observed cases. Medial meniscal injury located on the craniolateral border was most detected on arthroscopy (n = 9) and was detected on CTA in five cases, but on ultrasonography in 0 cases. Detection of articular cartilage defects on the medial femoral condyle was most detected with arthroscopy (24/25, 96% cases) and was also detected on CTA in 12/20 (60%) cases with a significant disagreement identified between modalities (P = 0.02). Cranial and caudal cruciate ligament defects were detected on CTA in 6/22 (27.3%) and 7/19 (36.8%) cases, respectively, and with arthroscopy in 3/25 (12%) and 2/25 (8%) cases, respectively. The use of CTA detected more defects in the cruciate ligaments, proximal tibia, and ligament entheses than the other diagnostic methods, but was not reliable for detection of articular cartilage damage on the medial femoral condyle.

A comparison of arthroscopy to ultrasonography for identification of pathology of the equine stifle

REASONS FOR PERFORMING STUDY To evaluate and compare the diagnostic capability of arthroscopy and ultrasonography for the detection of pathological change in equine stifle joints. Although descriptions of the arthroscopic and ultrasonographic boundaries of the normal femorotibial joint exist, there are few examples in the literature comparing the pathological changes observed with each imaging modality. OBJECTIVES To evaluate and compare arthroscopic and ultrasonographic examinations for characterising pathological change in the stifle joint. To describe how the results of arthroscopic and ultrasonographic examinations may differ in characterising the severity of lesions and to evaluate which lesions are best assessed with each modality. STUDY DESIGN Retrospective review of ultrasonographic and arthroscopic examinations. METHODS The structures of the stifle joint were evaluated and graded for pathological change by scoring arthroscopic and ultrasonographic examinations. The presence and severity of the lesions were then compared between each modality. RESULTS Medial meniscal lesions were detected more often with ultrasonography than with arthroscopy. Conversely, arthroscopy was better for detection of cranial medial meniscotibial ligament (CrMMTL) tearing. Articular cartilage defects were best detected with arthroscopy and periarticular osteophytes of the medial femoral condyle with ultrasonography. Four cases had defects within one of the patellar ligaments, all of which were only characterised with ultrasonography. CONCLUSIONS Ultrasonography and arthroscopy should be combined to best evaluate pathology of the stifle, since each modality has its own limitations depending on the location and type of lesion.

New concepts in standing advanced diagnostic equine imaging.

This article addresses the clinical application of magnetic resonance imaging (MRI) and computed tomography (CT) as applied to the standing equine patient. This discussion includes the logistics, advantages, disadvantages, and limitations of imaging a standing horse. In addition, a brief review is given of the physics of these modalities as applied in clinical practice, and the currently available hardware and software required by these techniques for image acquisition and artifact reduction. The appropriate selection of clinical cases for standing MRI and CT is reviewed, focusing on cases that are capable of undergoing standing surgeries following lesion diagnosis.