Use of equine cadaver limb models to enhance veterinary student self-efficacy during arthrocentesis.

OBJECTIVE: To determine if equine cadavers modified with joint distension would yield higher fluid volumes, require fewer needle redirects, and improve student self-efficacy. SAMPLE: 19 third-year veterinary students. METHODS: Voluntary participation was sought during 4 sessions of an equine arthrocentesis and diagnostic analgesia laboratory. Half of the sessions were provided with unmodified cadavers and half were provided with cadavers modified with joint distention. Prior to and after the laboratory, participating students completed surveys regarding their self-efficacy with arthrocentesis of the metacarpophalangeal and distal interphalangeal joints. During the study, the number of needle redirects and the volume of fluid obtained was recorded. RESULTS: Increased fluid volumes were obtained from the modified metacarpophalangeal and distal interphalangeal joints. No difference was identified in number of needle redirects between cadaver types for either joint. Self-efficacy scores increased at the end of the laboratory for arthrocentesis of the metacarpophalangeal joint in both modified and unmodified groups. Self-efficacy scores increased at the end of the laboratory for arthrocentesis of the distal interphalangeal joint for the modified but not unmodified groups. CLINICAL RELEVANCE: Modified equine cadavers provided a higher fluid yield following arthrocentesis compared to unmodified cadavers, but despite this, multiple attempts were required for proper needle placement. Performing equine arthrocentesis improved student self-efficacy with the task. Given our results, the model used for introduction to performing equine arthrocentesis may be less important than practice with the skill. In order to improve proficiency and self-efficacy, equine arthrocentesis should be provided multiple times throughout the veterinary curriculum.

Investigation of synovial fluid lubricants and inflammatory cytokines in the horse: a comparison of recombinant equine interleukin 1 beta-induced synovitis and joint lavage models.

BACKGROUND: Lameness is a debilitating condition in equine athletes that leads to more performance limitation and loss of use than any other medical condition. There are a limited number of non-terminal experimental models that can be used to study early inflammatory and synovial fluid biophysical changes that occur in the equine joint. Here, we compare the well-established carpal IL-1ß-induced synovitis model to a tarsal intra-articular lavage model, focusing on serial changes in synovial fluid inflammatory cytokines/chemokines and the synovial fluid lubricating molecules lubricin/proteoglycan 4 and hyaluronic acid. The objectives of this study were to evaluate clinical signs; synovial membrane and synovial fluid inflammation; and synovial fluid lubricants and biophysical properties in response to carpal IL-1ß synovitis and tarsal intra-articular lavage. RESULTS: Hyaluronic acid (HA) concentrations, especially high molecular weight HA, and synovial fluid viscosity decreased after both synovitis and lavage interventions. Synovial fluid lubricin concentrations increased 17-20-fold for both synovitis and lavage models, with similar changes in both affected and contralateral joints, suggesting that repeated arthrocentesis alone resulted in elevated synovial fluid lubricin concentrations. Synovitis resulted in a more severe inflammatory response based on clinical signs (temperature, heart rate, respiratory rate, lameness and joint effusion) and clinicopathological and biochemical parameters (white blood cell count, total protein, prostaglandin E2, sulfated glycosaminoglycans, tumor necrosis factor-α and CC chemokine ligands - 2, - 3, - 5 and - 11) as compared to lavage. CONCLUSIONS: Synovial fluid lubricin increased in response to IL-1ß synovitis and joint lavage but also as a result of repeated arthrocentesis. Frequent repeated arthrocentesis is associated with inflammatory changes, including increased sulfated glycosaminoglycan concentrations and decreased hyaluronic acid concentrations. Synovitis results in more significant inflammatory changes than joint lavage. Our data suggests that synovial fluid lubricin, TNF-α, CCL2, CCL3, CCL5, CCL11 and sGAG may be useful biomarkers for synovitis and post-lavage joint inflammation. Caution should be exercised when performing repeated arthrocentesis clinically or in experimental studies due to the inflammatory response and loss of HA and synovial fluid viscosity.

Influence of clipping on bacterial contamination of canine arthrocentesis sites before and after skin preparation.

OBJECTIVE: To determine the influence of hair removal as part of the aseptic skin preparation of canine arthrocentesis sites and to characterize the bacterial flora remaining after aseptic skin preparation. STUDY DESIGN: Randomized controlled trial. STUDY POPULATION: Thirteen shorthaired beagle-cross dogs. METHODS: A coin toss was used to randomly determine to have one carpus, elbow, tarsus, and stifle clipped. The contralateral side was left unclipped. Aseptic skin preparation was performed on all sites with 4% chlorhexidine followed by 70% isopropyl alcohol. The skin of each site was sampled for aerobic and anaerobic bacterial cultures before and after aseptic skin preparation. Bacterial cultures were submitted for laboratory testing to determine the colony-forming units (CFU) of bacteria and bacterial species isolated for each site. RESULTS: Each group (clipped and unclipped) included 52 sites. Aseptic skin preparation reduced bacterial CFU in both groups. There was no association between values for CFU per milliliter after skin preparation of dogs and side (P = .07), joint (P = .71), pre-aseptic skin preparation CFU (P = .94), or clipping (P = .42). Staphylococcus spp were the most common of the bacterial species cultured. CONCLUSION: In clean shorthaired dogs without visible evidence of dermatological disease, leaving arthrocentesis sites unclipped rather than performing traditional surgical clipping did not result in increased bacterial skin counts after aseptic skin preparation. CLINICAL SIGNIFICANCE: In this study we did not find evidence to support that clipping of canine arthrocentesis sites is required for effective aseptic skin preparation. A prospective clinical trial is required to determine whether a change in practice would be associated with increased morbidity.

Ultrasound-guided arthrocentesis of the temporomandibular joint in healthy adult horses is equivalent to blind arthrocentesis.

Equine temporomandibular joint (TMJ) diseases are increasingly recognized as a problem for the well-being and performance of horses. Diagnosis is confounded by overlap of clinical signs associated with pathology of the oral cavity, poll, and cervical vertebrae. Arthrocentesis for intra-articular analgesia, sampling of synovial fluid, and medication is needed for diagnostic and therapeutic purposes. Ultrasound features of the normal TMJ and a blind arthrocentesis technique have been described, but a systematic approach to ultrasound-guided (USG) arthrocentesis has not been reported. Ultrasound guidance allows visualization of the TMJ that may prove beneficial in cases when pathology, abnormal anatomy, or clinician inexperience make blind arthrocentesis difficult. We hypothesized that USG arthrocentesis would result in fewer needle repositions than blind arthrocentesis. We also aimed to assess synovial fluid parameters for normal equine TMJs. A prospective randomized method comparison with crossover experimental design compared the number of needle positionings required for accurate injection of the TMJ using each technique. Arthrocentesis technique and operator experience were tested using cadavers and two operators. Injection success was confirmed using CT. The radiologist then applied both techniques in normal live horses. No statistically significant difference was noted between arthrocentesis techniques or operators (P > .05). No complications were observed in live horses following either technique. Synovial fluid parameters were largely within the normal range expected for other synovial joints. Either blind or USG arthrocentesis of the equine TMJ can be performed with minimal prior operator experience. Ultrasound-guided arthrocentesis is an alternative method and can be considered in cases with altered anatomy.

Temporomandibular joint arthrocentesis in a rabbit model: technique and recommendations in the study of temporomandibular disorders.

INTRODUCTION: Arthrocentesis has been used in the temporomandibular joint (TMJ) to analyze components of the synovial fluid or as a therapeutic procedure associated or not with the administration of a drug. The rabbit is one of the most commonly used animal species as a model for pathologies that affect the TMJ. The aim of this study was to propose a specific technique to perform arthrocentesis on the rabbit TMJ, emphasizing descriptions of reference points and measurements for a successful puncture without complications. MATERIALS AND METHODS: Fourteen adult rabbits (Oryctolagus cuniculus) were used. The project was approved by the Scientific Ethics Committee of the Universidad de La Frontera (File Nº083/2016). RESULTS: The description of the technique was divided into three steps: 1) Location of the rabbit TMJ, 2) Positioning of the needles in the TMJ, and 3) Passage of fluid through the TMJ. CONCLUSIONS: This arthrocentesis technique could help to simplify the procedure and give the investigator a guide for joint washing and extraction of synovial fluid in the rabbit TMJ.

Effects of repeated arthrocentesis on systemic cytokine expression and leukocyte population in young horses challenged with intra-articular lipopolysaccharide.

Osteoarthritis (OA) is a prevalent and economically costly source of lameness in the athletic horse. Previous studies investigating OA pathology have focused on localized trauma to the articular cartilage of a joint, largely ignoring the systemic immune status of the animal. In this study, yearling Quarter Horses were used to evaluate systemic cytokine gene expression and circulating leukocytes following a localized intra-articular inflammatory insult of the endotoxin, lipopolysaccharide (LPS). Treatments for the 35-d experiment included an intra-articular injection of 0.25 ng (n = 7) or 0.50 ng (n = 6) of LPS obtained from Escherichia coli O55:B5 or sterile lactated Ringer's solution (n = 6; control) into the radial carpal joint. Blood and synovial fluid samples were collected at preinjection hour 0 and 2, 6, 12, and 24 h postinjection. Synovial fluid was obtained for a companion study. Total RNA was isolated from plasma leukocytes and real-time PCR was used to determine relative gene expression of the cytokines interleukin (IL)-1beta (ß), IL-6, IL-8, IL-10, and tumor necrosis factor-alpha (TNF-α). Total leukocyte subpopulations and differentials were performed using a cell counter. Data were analyzed using the PROC MIXED procedure of SAS. Gene expression of all cytokines were unaffected by intra-articular treatment. However, IL-1ß increased above baseline beginning at hour 6 and remained elevated to 24 h (P = 0.04). In contrast, IL-6 decreased from hours 6 to 12 and then increased to 24 h (P = 0.02). Levels of TNF-α increased at 6 and 12 h (P = 0.01) postinjection. Only IL-8 exceeded a 2-fold change in expression (P = 0.01), peaking at 12 h and indicating greater responsiveness to arthrocentesis when compared with other cytokines. No treatment effects on the leukocyte population were observed; however, total circulating leukocytes increased over time (P = 0.04), peaking at 6 h postinjection. Similarly, an increase over time was observed in monocytes (P = 0.02) and in platelets (P = 0.01) at 24 h postinjection. The results indicate that regardless of treatment, a mild immune response was elicited, which may be due to repeated arthrocentesis. Future experiments should consider the effects of arthrocentesis and potential systemic inflammatory response, even in control animals, when administering intra-articular LPS to young horses.

Ultrasonographic anatomy of the atlanto-occipital region and ultrasound-guided cerebrospinal fluid collection in rabbits (Oryctolagus cuniculus).

Cerebrospinal fluid analyses are important for diagnosis of neurologic problems in rabbits and for translational research projects using rabbits as models. Blind puncture of the cisterna magna is the current standard technique for sampling cerebrospinal fluid in this species. However, the complexity and small size of the cisterna magna and surrounding structures are limitations of this technique. Aims of this prospective, anatomic, pilot study were to (1) describe the normal anatomy of the atlanto-occipital region, (2) describe ultrasonographic anatomic landmarks, and (3) develop and evaluate a technique for ultrasound-guided puncture of the cisterna magna for cerebrospinal fluid sampling in rabbits. Thirty healthy rabbits were included and the study was conducted in three stages. Three rabbit cadavers were used for the first stage of the study. Then, the second stage was completed using 13 rabbit cadavers. Finally, the third stage was completed in 14 live rabbits. The ultrasound-guided puncture performed in 13 cadavers was successful at the first attempt in 10 cases, and at the second attempt in the remaining three cases. In the in vivo study, the ultrasound-guided puncture was successful in all 14 cases, without signs of complications. Findings supported the use of ultrasound-guided puncture of the cisterna magna as a safe technique that may be used routinely or when the sample of cerebrospinal fluid cannot be obtained with the blind technique in rabbits.

Changes in concentrations of haemostatic and inflammatory biomarkers in synovial fluid after intra-articular injection of lipopolysaccharide in horses.

BACKGROUND: Septic arthritis is a common and potentially devastating disease characterized by severe intra-articular (IA) inflammation and fibrin deposition. Research into equine joint pathologies has focused on inflammation, but recent research in humans suggests that both haemostatic and inflammatory pathways are activated in the joint compartment in arthritic conditions. The aim of this study was to characterize the IA haemostatic and inflammatory responses in horses with experimental lipopolysaccharide (LPS)-induced joint inflammation. Inflammation was induced by IA injection of LPS into one antebrachiocarpal joint of six horses. Horses were evaluated clinically with subjective grading of lameness, and blood and synovial fluid (SF) samples were collected at post injection hours (PIH) -120, -96, -24, 0, 2, 4, 8, 16, 24, 36, 48, 72 and 144. Total protein (TP), white blood cell counts (WBC), serum amyloid A (SAA), haptoglobin, iron, fibrinogen, thrombin-antithrombin (TAT) and d-dimer concentrations were assessed in blood and SF. RESULTS: Intra-articular injection of LPS caused local and systemic signs of inflammation including increased rectal temperature, lameness and increased joint circumference and skin temperature. Most of the biomarkers (TP, WBC, haptoglobin, fibrinogen and TAT) measured in SF increased quickly after LPS injection (at PIH 2-4), whereas SAA and d-dimer levels increased more slowly (at PIH 16 and 144, respectively). SF iron concentrations did not change statistically significantly. Blood WBC, SAA, haptoglobin and fibrinogen increased and iron decreased significantly in response to the IA LPS injection, while TAT and d-dimer concentrations did not change. Repeated pre-injection arthrocenteses caused significant changes in SF concentrations of TP, WBC and haptoglobin. CONCLUSION: Similar to inflammatory joint disease in humans, joint inflammation in horses was accompanied by an IA haemostatic response with changes in fibrinogen, TAT and d-dimer concentrations. Inflammatory and haemostatic responses were induced simultaneously and may likely interact. Further studies of interactions between the two responses are needed for a better understanding of pathogenesis of joint disease in horses. Knowledge of effects of repeated arthrocenteses on levels of SF biomarkers may be of value when markers are used for diagnostic purposes.

Evaluation of a caudolateral approach for arthrocentesis and injection of the equine elbow joint.

The objectives of this study were to evaluate the likelihood of successful arthrocentesis of the equine elbow joint using the caudolateral approach and to determine if the deep branch of the radial nerve (DBRN) varies in its proximity to the site of centesis. Methylene blue (MB) was injected into 71 elbow joint specimens immediately caudal to the lateral collateral ligament using a 3.8-cm needle advanced to its hub. The elbow joints were dissected, staining of the synovial structures assessed and the proximity of DBRN to the site of centesis evaluated. The articular cartilage of all 71 joints was stained with MB. The location of DBRN did not vary substantially among the specimens and did not course close to the site of centesis. Direct communication was found between the bursa of the tendon of the ulnaris lateralis muscle and the elbow joint in 41 of 71 specimens (57.8 per cent). The caudolateral approach for centesis of the equine elbow joint, performed by inserting a needle 3.8-cm, was found to be reliable. Radial nerve paralysis reported to be caused by injection of local anaesthetic solution using the caudolateral approach may be due to diffusion of the solution from the dorsal pouch rather than from leakage at the site of centesis.

Comparison of the efficacy of prednisone and cyclosporine for treatment of dogs with primary immune-mediated polyarthritis.

OBJECTIVE: To compare efficacy between cyclosporine and prednisone for treatment of primary immune-mediated polyarthritis (IMPA) in dogs. DESIGN: Randomized controlled clinical trial. ANIMALS: 20 client-owned dogs with primary IMPA. PROCEDURES: Dogs were randomly assigned to receive prednisone (starting at 1 mg/kg [0.45 mg/lb], PO, q 12 h; n = 10) or cyclosporine (5 mg/kg [2.3 mg/lb], PO, q 12 h; 10) for 90 days. Cyclosporine-treated dogs also received carprofen, tramadol, or both for the first 7 days for analgesia. Data collection, physical examination, and cytologic analysis of synovial fluid samples were performed on days 0, 14, 45, and 90. Trough whole blood cyclosporine concentrations were determined on days 7 to 17 for cyclosporine-treated dogs. Treatment failure was defined as lack of clinical improvement by day 14, lack of cytologic improvement by day 45, or need to change treatment because of adverse effects. RESULTS: Treatment was successful for 7 prednisone-treated dogs and 7 cyclosporine-treated dogs. Absence of synovial fluid cytologic abnormalities on day 45 was identified for 5 prednisone-treated dogs and 8 cyclosporine-treated dogs. Prednisone-treated dogs were more likely to develop polyuria, polydipsia, and polyphagia than were cyclosporine-treated dogs. Opportunistic infections (ie, demodicosis or Erysipelothrix bacteremia) were identified in 2 cyclosporine-treated dogs and 0 prednisone-treated dogs, and diarrhea developed in 1 cyclosporine-treated dog, requiring treatment discontinuation. CONCLUSIONS AND CLINICAL RELEVANCE: Although the number of dogs evaluated was small, limiting generalizability, results of this study suggested that cyclosporine offers promise as a suitable alternative to prednisone for treatment of IMPA in dogs.

Assessing the Effectiveness of a Cadaveric Teaching Model for Performing Arthrocentesis with Veterinary Students.

The purpose of this study was to determine if a recently developed cadaveric canine model was an effective tool for teaching arthrocentesis to fourth-year veterinary students. Arthrocentesis is an important diagnostic tool and technical skill that can be difficult to teach in the clinical setting. Eighteen fourth-year veterinary students participated in a within-subjects experiment that evaluated their ability to successfully perform arthrocentesis in the canine model and in an unmodified control cadaver. Students completed an online survey about the experience. Ability to perform the procedure was assessed by monitoring the number of attempts and redirects required to enter the joint and by recording any volume recovered from the arthrocentesis. In both phases of the study, the participants were able to aspirate a measurable volume of fluid from the joints of the model. Participants recorded an increase in confidence with arthrocentesis after using the model in the first phase of the study and unanimously supported inclusion of the exercise in future teaching situations.

In vitro assessment of bacterial translocation during needle insertion through inoculated culture media as a model of arthrocentesis through cellulitic tissue.

OBJECTIVE: To determine by use of an in vitro model the potential for translocating sufficient numbers of bacteria into a joint during arthrocentesis through cellulitic tissue to cause sepsis. SAMPLE: Culture media containing 4 concentrations of Staphylococcus aureus and needles of 3 sizes. PROCEDURES: Needles (22, 20, and 19 gauge) were inserted through Mueller-Hinton agar that contained known concentrations of S aureus (10(3),10(4),10(5), and 10(6) CFUs/mL). After a needle exited through the medium, any agar plug within the needle bore was ejected into a sterile syringe and the contaminated portion of the needle was harvested. Sterile saline (0.9% NaCl) solution was used to emulsify the agar plug and wash the contaminated portion of the needle. The resulting solution was cultured to determine the number of bacterial CFUs that could be deposited into a joint during arthrocentesis through contaminated tissue. RESULTS: Needle gauge and bacterial concentration were both associated with the number of bacterial CFUs deposited after insertion through contaminated agar. Although all needle sizes were capable of bacterial translocation sufficient to cause septic arthritis, ORs for 20- and 22-gauge needles translocating > 33 CFUs of S aureus were significantly higher than the OR for a 19-gauge needle. The ORs for 20- or 22-gauge needles translocating > 33 CFUs of S aureus (the minimum population of S aureus known to cause joint sepsis) were 0.22. CONCLUSIONS AND CLINICAL RELEVANCE: Results for this in vitro model indicated that caution should be used when performing arthrocentesis through cellulitic tissue.

Retrospective evaluation of the efficacy of isolating bacteria from synovial fluid in dogs with suspected septic arthritis.

OBJECTIVE: To evaluate the efficacy of synovial fluid culture in obtaining the causative organism from dogs with suspected septic arthritis. METHODS: In this retrospective evaluation, synovial fluid cytology and microbiology submissions from dogs with suspected septic arthritis from March 2007 to August 2011 were reviewed. Synovial fluid cytology consistent with joint sepsis was identified. Cultures of synovial fluid from dogs with clinical histories and abnormalities consistent with septic arthritis were used to evaluate the efficacy of bacterial isolation. RESULTS: In total, 36 dogs met the inclusion criteria. Initial aerobic cultures of joint fluid yielded bacterial growth in 44% of these dogs. All anaerobic cultures were negative. In 19% of the dogs with positive cultures, antibiotics had been administered prior to arthrocentesis compared with 10% of dogs with negative cultures. There was no association between culture efficacy and the administration of antimicrobial treatment prior to synovial fluid culture or recent surgery involving the affected joint (P=0.637 and P=0.106, respectively). CONCLUSION: Culture of synovial fluid from dogs with suspected septic arthritis has a low yield, necessitating a more effective means of identifying bacteria from suspected septic joints in dogs.