Blind Versus Ultrasound-Guided Low-Volume Perineural Injection of Tibial and Fibular Nerves in Equine Cadaver Limbs.

Techniques for local anesthesia of the tibial (TN) and superficial and deep fibular nerves (FNs) in horses are well established. Ultrasound-guided perineural blocks can identify the nerve location, reduce the anesthetic volume needed and avoid needle misplacement. The aim of this research was to compare the success of blind perineural injection technique (BLIND) to ultrasound-guided technique (USG). Fifteen equine cadaver hindlimbs were divided into two groups. Perineural injection of the TN and FNs was performed using a mixed solution of radiopaque contrast, saline and food dye. BLIND (n = 8) used 15 mL for the TN and 10 mL for each fibular nerve. USG (n = 7) used 3 mL for the TN and 1.5 mL for each fibular nerve. The limbs were radiographed immediately after injections and sectioned transversally to evaluate the diffusion and presence of the injectate adjacent to the TN and FNs. The presence of dye immediately adjacent to the nerves was considered a successful perineural injection. No statistically significant difference was observed between groups for success. Distal diffusion of injectate following perineural injection of the TN was significantly less for USG compared to BLIND. Proximal, distal and medial diffusion of injectate following perineural injection of FNs was significantly less for USG compared to BLIND. Low-volume USG results in less diffusion but similar success compared to BLIND leaving it up to veterinarian preference when selecting a technique.

The Effect of Capacitive-Resistive Electrical Therapy on Neck Pain and Dysfunction in Horses.

Neck pain and stiffness are increasingly recognized in horses and often treated using multimodal pharmaceutical and rehabilitation approaches. In humans, deep tissue heating is reported to reduce neck pain and increase flexibility. The objective of this project was to determine the effects of capacitive-resistive electrical therapy on neck pain and stiffness in horses. A blinded, randomized, controlled clinical trial with 10 horses assigned to active and 10 horses assigned to sham treatment groups. Neck pain, stiffness, and muscle hypertonicity were assessed by manual palpation. Forelimb postural stability was evaluated using a portable media device with built-in inertial sensing components. All outcome parameters were recorded once weekly for four weeks. Using manufacturer recommendations, the treatment group received active capacitive-resistive electrical therapy to the lower cervical region (C4-C7), twice weekly for a total of six treatments, while the control group received a sham (inactive) treatment. Data was analyzed using a mixed model that was fit separately for each response variable. There were no significant differences noted over time or between groups for any outcome parameter evaluated. While neck pain and stiffness decreased by week three in both groups, the improvement was not significant. Limitations include the lack of a definitive pathoanatomic diagnosis of cervical pathology and in vivo temperature measurements. Capacitive-resistive electrical therapy was ineffective in reducing neck pain and dysfunction using the recommended treatment protocols. No short-term adverse effects were noted. Specific clinical applications and effective treatment parameters need further evaluation.

An Alternate Radiographic Guided Technique for Injection of the Equine Navicular Bursa Using a 40 mm (1.5-inch) 20-Gauge Needle: A Pilot Study.

Injection of the equine navicular bursa can be technically challenging, and inadvertent penetration of other synovial structures is common using previously described techniques. When injecting the navicular bursa, inadvertent penetration of other synovial structures and hoof configuration can affect success rate, especially when performed by inexperienced operators. The aim of this study is to describe an alternate radiographic guided technique for injection of the equine navicular bursa that consistently avoids penetration of the distal interphalangeal joint using a 40 mm (1.5-inch) 20-gauge needle. This ex vivo pilot study compared the success rate, needle redirection rate, and rate of inadvertent synovial penetration of a novel injection technique for the equine navicular bursa between operators with three differing levels of experience in equine veterinary medicine (1 year, 8 years, >30 years). There was no significant difference in success rate between operators regardless of level of experience or hoof configuration, and inadvertent penetration of other synovial structures was highly unlikely. Thus, using the described technique, injection of the navicular bursa can be performed by individuals of various experience levels in equine veterinary practice, and can be achieved with a high success rate with little chance of inadvertent penetration of other synovial structures regardless of hoof configuration.

Microfracture Augmentation With Trypsin Pretreatment and Growth Factor-Functionalized Self-assembling Peptide Hydrogel Scaffold in an Equine Model.

BACKGROUND: Microfracture augmentation can be a cost-effective single-step alternative to current cartilage repair techniques. Trypsin pretreatment combined with a growth factor-functionalized self-assembling KLD hydrogel ("functionalized hydrogel") has been shown to improve overall cartilage repair and integration to surrounding tissue in small animal models of osteochondral defects. HYPOTHESIS: Microfracture combined with trypsin treatment and a functionalized hydrogel will improve reparative tissue quality and integration as compared with microfracture alone in an equine model. STUDY DESIGN: Controlled laboratory study. METHODS: Bilateral cartilage defects (15-mm diameter) were created on the medial trochlear ridge of the femoropatellar joints in 8 adult horses (16 defects total). One defect was randomly selected to receive the treatment, and the contralateral defect served as the control (microfracture only). Treatment consisted of 2-minute trypsin pretreatment of the surrounding cartilage, subchondral bone microfracture, and functionalized hydrogel premixed with growth factors (platelet-derived growth factor and heparin-binding insulin-like growth factor 1). After surgery, all horses were subjected to standardized controlled exercise on a high-speed treadmill. Clinical evaluation was conducted monthly, and radiographic examinations were performed at 2, 16, 24, 32, 40, and 52 weeks after defect creation. After 12 months, all animals were euthanized. Magnetic resonance imaging, arthroscopy, gross pathologic evaluation of the joint, histology, immunohistochemistry, and biomechanical analyses were performed. Generalized linear mixed models (with horse as random effect) were utilized to assess outcome parameters. When P values were <.05, pairwise comparisons were made using least squares means. RESULTS: Improved functional outcome parameters were observed for the treatment group, even though mildly increased joint effusion and subchondral bone sclerosis were noted on imaging. Microscopically, treatment resulted in improvement of several histologic parameters and overall quality of repaired tissue. Proteoglycan content based on safranin O-fast green staining was also significantly higher in the treated defects. CONCLUSION: Trypsin treatment combined with functionalized hydrogel resulted in improved microfracture augmentation. CLINICAL RELEVANCE: Therapeutic strategies for microfracture augmentation, such as those presented in this study, can be cost-effective ways to improve cartilage healing outcomes, especially in more active patients.

Current joint therapy usage in equine practice: Changes in the last 10 years.

BACKGROUND: Osteoarthritis is a common clinical condition in the performance horse. In the last 10 years, there has been substantial growth in understanding of the disease and in the development of novel therapies. OBJECTIVES: To document changes in clinical use of joint therapies over the past 10 years. We also aimed to understand how newly developed therapies have been added to routine clinical practice. STUDY DESIGN: Survey of veterinary professionals. METHODS: We administered an electronic survey to members of the American Association of the Equine Practitioners. Questions from a similar survey in 2009 were repeated and new questions were added. The responses were tabulated, analysed and compared to those of the previous survey. RESULTS: A total of 407 completed surveys were returned. There were no significant differences between the current and previous surveys with respect to demographic parameters. Triamcinolone acetonide (TA) remained the most common corticosteroid used to treat high-motion joints. Methylprednisolone acetate (MPA) remained the most common corticosteroid to treat low-motion joints. The use of MPA for high-motion joints was significantly more common in 2009 than in 2019 (odds ratio [OR]: 2.38, 95% confidence interval [CI]: 1.66-3.42, P = .001). Biological therapies became more popular, and the likelihood of respondents reporting having used autologous conditioned serum was substantially higher in 2019 than in 2009 (OR: 4.24, 95% CI: 3.16-5.68, P < .001). Concomitant use of antibiotics with intra-articular medications became more common as well. MAIN LIMITATIONS: This is a report of survey data and not directly measured treatments. CONCLUSIONS: There is a decrease in the use of MPA to treat high-motion joints. The use of biological therapies in joints has become more prevalent. There are clear differences in the use of joint therapies over time. While some differences agree with the scientific evidence, others are not fully concordant or are in direct conflict with the scientific literature.

Trypsin Pre-Treatment Combined With Growth Factor Functionalized Self-Assembling Peptide Hydrogel Improves Cartilage Repair in Rabbit Model.

The objective of this study was to improve cartilage repair and integration using self-assembling KLD hydrogel functionalized with platelet-derived growth factor-BB and heparin-binding insulin-like growth factor-1 with associated enzymatic trypsin pre-treatment of the native cartilage. Bilateral osteochondral defects were created at the central portion of the femoral trochlear groove of 48 skeletally mature, white New Zealand rabbits. One limb received a randomly assigned treatment and the contralateral limb served as the control. Treated defects were exposed to trypsin for 2 min and filled with self-assembling KLD hydrogel only, or associated to growth factors. All control limbs received KLD hydrogel alone or received only trypsin but not hydrogel. Ninety days post-defect creation, the rabbits were euthanized and magnetic resonance imaging, radiography, macroscopic evaluation, histology, and immunohistochemistry of the joint and repaired tissue were performed. Mixed model analyses of variance were utilized to assess the outcome parameters and individual comparisons were performed using Least Square Means procedure and differences with p-value < 0.05 were considered significant. Trypsin enzymatic pre-treatment improved cellular morphology, cluster formation and subchondral bone reconstitution. Platelet-derived growth factor-BB improved subchondral bone healing and basal integration. Heparin-binding insulin-like growth factor-1 associated with platelet-derived growth factor improved tissue and cell morphology. The authors conclude that self-assembling KLD hydrogel functionalized with platelet-derived growth factor and heparin-binding insulin-like growth factor-1 with associated enzymatic pre-treatment of the native cartilage with trypsin resulted in an improvement on the cartilage repair process. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2307-2315, 2019.

Enzyme Pretreatment plus Locally Delivered HB-IGF-1 Stimulate Integrative Cartilage Repair In Vitro.

IMPACT STATEMENT: A critical attribute for the long-term success of cartilage defect repair is the strong integration between the repair tissue and the surrounding native tissue. Current approaches utilized by physicians fail to achieve this attribute, leading to eventual relapse of the defect. This article demonstrates the concept of a simple, clinically viable approach for enhancing tissue integration via the combination of a safe, transient enzymatic treatment with a locally delivered, retained growth factor through an in vitro hydrogel/cartilage explant model.

Significant hematocrit decrease in healthy horses during clinical anesthesia / Redução significante dos valores de hematócrito em equinos saudáveis durante anestesia

Xylazine (XYL) and acepromazine (ACP) are known to decrease the hematocrit (HT) of horses when administered alone. However in routine anesthesia these drugs are administered by associations which ultimate effect in the HT is unknown but may cause false impressions about the hydration status, blood loss and red blood cell indices. The objective of this study was to characterize the values of HT in horses anesthetized with XYL, ACP, ketamine, midazolam, guaiphenesin, isoflurane and ephedrine. Twenty healthy horses were premedicated with either XYL 0.8 mg/kg (XYL group, n=10) or XYL 0.5 mg/kg plus ACP 0.05 mg/kg (XYL+ACP group, n=10). Anesthesia was induced with ketamine, midazolam and guaiphenesin and maintained with isoflurane. Ephedrine was infused for cardiovascular support. HT, vital parameters and blood gas values were evaluated at baseline, between each drug administration, after standing and 24 hours after baseline (24hBL). The HT started to decrease 17 and 40 minutes after premedication in XYL group and XYL+ACP group, respectively (p<0.05). The maximum decrease of 19% in XYL group and 17% in XYL+ACP group was observed after 1 hour of premedication (p<0.05). In both groups HT remained low for longer than 180 minutes and returned to baseline at 24hBL. A significant HT decrease should be considered in anesthetized healthy horses receiving XYL, ACP, ketamine, midazolam, guaiphenesin, isoflurane and ephedrine.

A administração isolada de xilazina (XIL) e acepromazina (ACP) pode diminuir o hematócrito (HT) de equinos. Na rotina anestésica, estes fármacos são administrados em associações, cujo efeito final no HT não é conhecido, mas pode causar falsas impressões sobre o grau de hidratação, perda sanguínea e índices hematimétricos. O objetivo deste estudo foi caracterizar os valores de HT de equinos anestesiados com XYL, ACP, cetamina, midazolam, EGG, isofluorano e efedrina. Vinte equinos hígidos foram pré-tratados com XIL 0,8 mg/kg (grupo XIL, n=10) ou XIL 0,5 mg/kg associada à ACP 0,05 mg/kg (grupo XIL+ACP, n=10). A anestesia foi induzida com cetamina, midazolam e EGG e mantida com isofluorano. A efedrina foi utilizada para suporte cardiovascular. O HT, parâmetros vitais e hemogasometria foram avaliados no momento basal, entre administração de cada fármaco, após retorno à posição quadrupedal e 24 horas após momento basal (24hBL). A diminuição do HT iniciou-se 17 e 40 minutos após administração da medicação préanestésica no grupo XIL e grupo XIL+ACP, respectivamente (p<0,05). A queda máxima de 19% no grupo XIL e 17% no grupo XIL+ACP foi observada após 1 hora da administração da medicação pré-anestésica (p<0,05). Em ambos os grupos, o HT permaneceu baixo por mais de 180 minutos e retornou aos valores basais em 24hBL. Deve-se considerar a ocorrência de uma redução significativa do HT em equinos hígidos anestesiados com XYL, ACP, cetamina, midazolam, EGG, isofluorano e efedrina.