Objective:To develop and define a model of acute neck pain in an equine cervical articular process joint (APJ) using recombinant equine IL-1β (reIL-1β). Methods:12 horses in this experimental study received a randomly assigned, unilateral intra-articular injection of 50 ng (n = 6) or 100 ng (n = 6) of reIL-1β and saline (contralateral side as control) into the C5-to-C6 APJ. Blinded ultrasonographic, clinical, and biomechanical parameters were evaluated between 4 hours and 14 days. Results:There was a significant increase in APJ effusion on ultrasonographic examination that peaked at 24 hours (P = .0256; effect size, 0.8312; CI, 1.0594 to 0.629). There was a time effect on the clinical examination score (myofascial pain and stiffness) and a significant decrease in stride length and velocity at 24 hours. There was an adverse event (extravasation of injectate) in 1 horse. Conclusions:Ultrasonographic evidence of the presence and severity of APJ effusion was readily identified and tracked over time. Unilateral injection of the APJ with reIL-1β induced clinical signs of myofascial pain, neck stiffness, and gait adaptations. Using individual control horses, rather than a contralateral saline injection within the same horse, would improve our understanding of the clinical presentation of acute APJ pain using this model. Clinical Relevance:Diagnosing the presence, localization, and clinical effects of neck pain in horses remains challenging and would benefit from the establishment of an experimental model. The induction of acute synovitis using reIL-1β within the C5-to-C6 APJ opens the door for future studies to ultimately better understand equine cervical pain and dysfunction.

BACKGROUND:Pathological changes of the fetlock joint are well documented in Thoroughbreds, but little information is available describing the common radiographic findings in western performance horses with fetlock lameness. OBJECTIVES:To describe radiographic findings in western performance horses with fetlock lameness. It was hypothesised that the degree of lameness would correlate with the severity of radiographic findings. STUDY DESIGN:Retrospective case series. METHODS:Retrospective review (2012-2022) of horses with lameness isolated to the fetlock joint via intra-articular analgesia and corresponding radiographs was included. Signalment, lameness, flexion, and effusion grades were recorded. Radiographs were evaluated for presence, severity, and location of pathology. Subjective radiographic severity scores were assigned. Correlations between outcome parameters were evaluated with Spearman's correlation coefficient. Statistically significant changes in median lameness grades for each radiographic abnormality were determined using the Wilcoxon Rank Sum test. RESULTS:Ninety cases met inclusion criteria. Radiographic lesions were identified in 96.7% of cases. Distal cannon bone sclerosis, periarticular osteophytes, increased soft tissue opacity, proximal phalanx (P1) sclerosis, and subchondral bone (SCB) defects were most common. Horses with SCB cysts (median 3; Interquartile range (IQR) 2.25-3.75; p < 0.05), P1 fissures (median 3; IQR 3-3; p < 0.05), or proximal P1 sclerosis (median 2; IQR 2-3; p < 0.05) had significantly higher median lameness grades. No significant correlation was established between overall radiographic score and lameness grade (r = 0.16, p > 0.05). MAIN LIMITATIONS:Outcome parameters were not captured for every horse due to retrospective design. Diagnostic analgesia has inherent limitations with specificity and interpretation of results. Using multiple clinicians may have led to inconsistencies in lameness grade, flexion response, and improvement after diagnostic analgesia. CONCLUSIONS:Horses in this study demonstrated changes associated with chronic exercise-induced remodelling and degenerative joint disease. While the degree of lameness did not correlate with the overall radiographic score, certain radiographic findings-P1 sclerosis, SCB cysts, and P1 fissures-were correlated with a higher degree of lameness.

Objective:To (1) identify tissue-specific metabolic profiles of the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), and suspensory ligament (SL) and (2) evaluate metabolic profile differences in the SDFT, DDFT, and SL between the equine forelimb and hindlimb. Methods:2 SDFT, DDFT, and SL specimens were collected from the forelimbs and hindlimbs of 10 horses of mixed breed, age, and sex that were euthanized for other reasons. One specimen was processed for histology to confirm that there were no underlying soft-tissue pathologies. One specimen was processed for 2 forms of untargeted metabolomics: (1) gas chromatography-mass spectroscopy for polar metabolites and (2) UPLC-MS for nonpolar metabolites. Comparisons were made between tissue types (SDFT, DDFT, and SL) in the same limb and between limbs (forelimb and hindlimb) for the same tissue. Results:Metabolic differences, specifically in the taurine and glycerolipid pathways, were evident between the tendons and ligaments. Metabolic differences, including changes in trihexosylceramides and fatty acyls, were also seen when comparing the forelimbs and hindlimbs of the tendons and ligaments, respectively. Conclusions:The current study has established metabolic differences in tendons and ligaments in a group of metabolically healthy horses. Clinical Relevance:Understanding these metabolic differences may allow for exploration into targeted intervention strategies for these tissues that may prevent injury as well as promote healing and a return to function.

OBJECTIVE:(1) To evaluate the ability of western performance horses diagnosed with chondromalacia to return to performance; Specifically, the relationship between the grade of chondromalacia and the horses' ability to resume work; (2) To determine the impact of postoperative therapy on clinical outcomes. STUDY DESIGN:Retrospective case series. ANIMALS:Horses (n = 34). METHODS:Records of western performance horses with lameness localized to the stifle that underwent subsequent arthroscopy with chondromalacia as the most significant diagnosis were reviewed. Chondromalacia was surgeon-graded as slight, mild, moderate, or marked. Three evaluated categories of postoperative intra-articular therapy included: (1) bone marrow derived mesenchymal stem cells, (2) equine amniotic allograft product or (3) none. Outcome was defined as returning to previous level of work on a numeric scale (1-10). RESULTS:Chondromalacia and its degree of severity and focal vs. diffuse distribution identified arthroscopically did not show a significant association (p = .54, .40, respectively) or correlation (p = .18; R-value: 0.27) with the ability to return to athletic performance. The type of postoperative intra-articular therapy did not have any association with the horse returning to athletic work (p = .53). CONCLUSION:A statistically significant association between severity, distribution or subsequent postoperative therapy for stifle chondromalacia and the ability to return to work was not observed. CLINICAL SIGNIFICANCE:Compared to previously published reports, this study demonstrated a 74% more favorable prognosis for returning to some level of athletic work despite only 44% of horses returning to their previous level of performance.

Radiographs are a common diagnostic tool utilised during pre-purchase examinations, yet differences surround their interpretation among equine veterinarians. (1) To determine veterinarians' subjective impressions of a spectrum of radiographic abnormalities regarding suitability for purchase; (2) To determine how veterinarians' years in practice, primary discipline or board certification status influence their subjective impression of radiographic abnormalities, and (3) To determine how horses' discipline, current level of work (working at intended level vs. future prospect) and buyer intent (sell vs. retain ownership) influence veterinarians' subsequent recommendation. Worldwide electronic survey of veterinary professionals. Four radiographic series of navicular bones, tarsi, and stifles, representing varying degrees of pathological change (normal, mild, moderate and marked) were presented. Respondents ( n  = 211) graded their level of concern from 1 (no concern) to 10 (very concerned) based on the radiographs and case scenarios presented. Overall, as the grade of pathological change increased for each anatomical location, so did the level of veterinarian concern, but a wide range of answers were submitted for all grades of pathology. Board certified practitioners had a higher level of concern over marked radiographic changes of the navicular bone for both western performance and English sport horses as well as prospect horses (mean = 7.2 vs. 6.1; P  = 0.009; 95% CI for difference = [0.3, 2.0]). Board certified respondents had a lower level of concern over marked radiographic changes of the tarsus regardless of the performance status of the horse (mean = 7.1 vs. 8.0; P  = 0.008; 95% CI for difference = [−1.5, −0.2]). Western performance horse practitioners had a lower level of concern over mild radiographic changes of the tarsus regardless of the performance status of the horse (mean = 3.3 vs. 4.2; P  = 0.009; 95% CI for difference = [−1.6, −0.2]). Only one example of each pathological grade per anatomical region was presented. On survey radiographs, the perceived clinical relevance of radiographic abnormalities among equine practitioners differs widely, making purchase recommendations highly variable.

BACKGROUND:Significant distal interphalangeal joint (DIPJ) pathology, particularly affecting soft tissue and articular cartilage, is often not identifiable on radiographs but can be accompanied by joint capsule enthesopathy on the middle phalanx (P2), which can be readily identified. OBJECTIVES:To explore frequency and correlations between DIPJ capsule enthesopathy identified on magnetic resonance imaging (MRI) and radiographs and DIPJ articular cartilage abnormalities and other concurrent soft tissue or osseous pathology within the foot found on MRI. STUDY DESIGN:Retrospective descriptive case series. METHODS:Cases identified with DIPJ capsule enthesopathy on MRI and radiographs were retrospectively reviewed. Abnormalities were graded using a 4-point scale. Descriptive statistics and Spearman's rank correlations were used to analyse the relationship between the presence and grade of DIPJ capsule enthesopathy, lameness, and DIPJ intra-articular and collateral ligament abnormalities seen on MRI. RESULTS:MRI and radiographic studies of 21 feet with DIPJ capsule enthesopathy were analysed. DIPJ articular cartilage lesions were identified in 20/21 limbs (95%). There was no significant correlation between the degree of DIPJ capsule enthesopathy and the severity of articular cartilage lesions. DIPJ proliferative synovitis and osteophytes were present in the majority of limbs (91% and 95%), respectively. DIPJ collateral ligaments were abnormal in 52% of the limbs. With MRI-based assessment, DIPJ capsule enthesopathy grade was moderately positively correlated with DIPJ collateral ligaments' findings severity (r = 0.53, p = 0.01). MAIN LIMITATIONS:Retrospective character, no histopathology, studied cases limited to one referral centre, low case numbers and statistical power. CONCLUSIONS:The presence of DIPJ capsule enthesopathy on radiographs is a reliable finding to rule in DIPJ damage and support further case management, particularly in cases where advanced imaging is unavailable or desired.

BackgroundRadiographs are a common diagnostic tool utilised during pre-purchase examinations, yet differences surround their interpretation among equine veterinarians.Objectives(1) To determine veterinarians' subjective impressions of a spectrum of radiographic abnormalities regarding suitability for purchase; (2) To determine how veterinarians' years in practice, primary discipline or board certification status influence their subjective impression of radiographic abnormalities, and (3) To determine how horses' discipline, current level of work (working at intended level vs. future prospect) and buyer intent (sell vs. retain ownership) influence veterinarians' subsequent recommendation.Study designWorldwide electronic survey of veterinary professionals.MethodsFour radiographic series of navicular bones, tarsi, and stifles, representing varying degrees of pathological change (normal, mild, moderate and marked) were presented. Respondents (n = 211) graded their level of concern from 1 (no concern) to 10 (very concerned) based on the radiographs and case scenarios presented.ResultsOverall, as the grade of pathological change increased for each anatomical location, so did the level of veterinarian concern, but a wide range of answers were submitted for all grades of pathology. Board certified practitioners had a higher level of concern over marked radiographic changes of the navicular bone for both western performance and English sport horses as well as prospect horses (mean = 7.2 vs. 6.1; P = 0.009; 95% CI for difference = [0.3, 2.0]). Board certified respondents had a lower level of concern over marked radiographic changes of the tarsus regardless of the performance status of the horse (mean = 7.1 vs. 8.0; P = 0.008; 95% CI for difference = [-1.5, -0.2]). Western performance horse practitioners had a lower level of concern over mild radiographic changes of the tarsus regardless of the performance status of the horse (mean = 3.3 vs. 4.2; P = 0.009; 95% CI for difference = [-1.6, -0.2]).Main limitationsOnly one example of each pathological grade per anatomical region was presented.ConclusionsOn survey radiographs, the perceived clinical relevance of radiographic abnormalities among equine practitioners differs widely, making purchase recommendations highly variable.

OBJECTIVE:To evaluate the effects of a gene transfer approach to IL-1β inhibition in an equine osteochondral chip fragment model of joint injury using a self-complementary adeno-associated virus with interleukin receptor antagonist transgene cassette (scAAVIL-1ra), as posttraumatic osteoarthritis in horses, similar to people, is a significant clinical problem. ANIMALS:16 horses were utilized for the study. METHODS:All horses had an osteochondral chip fragment induced arthroscopically in one middle carpal joint while the contralateral joint was sham operated. Eight horses received either scAAVIL-1ra or saline in the osteoarthritis joint. Horses were evaluated over 70 days clinically (lameness, imaging, and biomarker analysis) and euthanized at 70 days and evaluated grossly, with imaging and histopathology. RESULTS:The following findings were statistically significant. Injection of scAAVIL-1ra resulted in high synovial fluid levels of IL-1ra (0.5 to 9 μg/mL) throughout the duration of the experiment (70 days). Over the duration, we observed scAAVIL-1ra to improve lameness (lameness score relative improvement of 1.2 on a scale of 0 to 5), cause suppression of prostaglandin E2 (a relative decline of 30 pg/mL), and result in histological improvement in articular cartilage (decreased chondrocyte loss and chondrone formation) and subchondral bone (less osteochondral splitting and osteochondral lesions). Within the synovial membrane of scAAVIL-1ra-treated joints, we also observed perivascular infiltration with CD3-positive WBCs, suggesting lymphocytic T-cell perivascular infiltration commonly observed with viral transduction. CLINICAL RELEVANCE:These data provide support for further evaluation and optimization of scAAVIL-1ra gene therapy to treat equine osteoarthritis.

Objective To investigate the cytokine release profile and histological response of human cartilage after exposure to autologous conditioned serum (ACS) and freeze-dried allogenic conditioned serum (FD-CS). Design Cartilage explants were collected from 6 patients undergoing total knee arthroplasty. ACS and FD-CS were created from patient serum samples. Cartilage samples were divided into 6 groups: (1) untreated control, (2) ACS, (3) FD-CS, (4) untreated interleukin (IL)-1β (5 ng/ml), (5) IL-1β + ACS, and (6) IL-1β + FD-CS. After 12 days, cartilage samples were analyzed with glycosaminoglycan (GAG) concentration normalized to wet weight while comparing cytokine concentrations, and histological scoring. Results There was a significant decrease in pathology scoring for ACS ( P = 0.0368) and FD-CS ( P = 0.0368) in the IL-1β injury groups compared with the untreated IL-1β insult group. ACS and FD-CS significantly mitigate the IL-1β induced increase in basic fibroblast growth factor (bFGF) ( P = 0.0009 and P = 0.0002, respectively). FD-CS showed a significant decrease in IL-1β concentration in the presence of IL-1β insult compared with the untreated IL-1β group ( P < 0.0001). ACS-treated samples had significantly higher concentration of tumor necrosis factor (TNF)-α independent of IL-1β when compared with samples not treated with biologics ( P = 0.0053). Conclusions Explanted osteoarthritic cartilage responds favorably and equivalently to treatment with ACS and FD-CS from a histological perspective. Both ACS and FD-CS were able to mitigate the IL-1β-induced increases in bFGF and FD-CS lowered IL-1β concentration while increasing interleukin-1 receptor antagonist (IL-1Ra) concentration. Although the cytokine profile of cartilage tissue explants treated with FD-CS appears to be different than that of ACS, this difference does not seem to affect biologic activity of FD-CS.

Introduction: Chondromalacia of the stifle has been historically reported to negatively impact the ability to return to performance, however this information for western performance horses specifically is lacking.

Objectives: Traditionally, knee injections for the treatment of knee osteoarthritis (OA) have included corticosteroid with local anesthetic and hyaluronic acid (HA), but more recent investigations have delved into the potential benefits of biologic injections such as platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC), and autologous conditioned serum (ACS). While positive clinical results have been seen with the clinical use of commercial ACS products, there are limitations currently precluding its widespread acceptance and use. These challenges include the preparation time and storage requirements, patient variability in both pro- and anti-inflammatory cytokine profiles, and lack of regulatory approval of a commercial product in the United States. The development of an allogenic freeze-dried ACS product with an unaltered cytokine profile that remains stable at room temperature and would allow for easy storage, transport, and delivery to clinical settings. The purpose of the present study is to (1) compare the composition of freeze-dried allogenic conditioned serum (FD-CS) to fresh ACS and (2) to investigate the response of human knee cartilage after exposure to FD-CS and ACS to determine whether freeze-drying (lyophilization) affects the biological activity of conditioned serum products. Methods: Cartilage explants were collected from 6 patients undergoing total knee arthroplasty. ACS and FD-CS were created from patient serum samples. Cartilage samples were divided into 6 groups: (1) untreated control, (2) control + ACS, (3) control + FD-CS, (4) IL-1β (5 ng/ml), (5) IL-1β + ACS, and (6) IL-1β + FD-CS. After 10 days of incubation, samples were analyzed and compared for DNA normalized glycosaminoglycan (GAG) content, cytokine contents, and histological characterization (Figure 1). Results: There was a significant decrease in pathology scoring for ACS (p = 0.0368) or FD-CS (p = 0.0368) in the presence of IL-1 compared to the control (Figure 2). Both ACS and FD-CS significantly mitigate the IL-1β induced increase in FGF (p = 0.0009 and p = 0.0002, respectively) (Figure 3). FD-CS showed a significant increase in IL-1Ra (Figure 4) and decrease in the IL-1β concentration in the presence of IL-1β compared to the control (p < 0.0001 and p < 0.0001). ACS treated samples had significantly higher concentration of TNF-α independent of IL-1 (p = 0.0053). Conclusions: Explanted osteoarthritic cartilage responds favorably and equivalently to treatment with ACS and FD-CS from a histological perspective. Both ACS and FD-CS were able to mitigate the IL-1β induced increases in FGF, and FD-CS lowers IL-1β concentration while increasing IL-1Ra concentration. While the cytokine profile of the FD-CS was slightly altered when compared to ACS, it does not affect its biologic activity.

Purpose/AimMetabolic disorders are risk factors for rotator cuff injuries, which suggests that the rotator cuff is sensitive to local metabolic fluctuations. However, the link between the metabolic microenvironment and pathologic features of acute tear versus chronic degeneration is currently unknown. The overarching goal of this study was to evaluate alterations in tendon metabolite profiles following acute tear or chronic degeneration of the rotator cuff. We hypothesized that injury types (acute tear vs. chronic degeneration) would result in distinct metabolite profiles relative to clinically unaffected tendon controls.Materials and MethodsWe utilized untargeted metabolomics to identify pathways that were altered at the time of rotator cuff repair (RCR; acute tear) or reverse total shoulder arthroplasty (rTSA; chronic degeneration) relative to total shoulder arthroplasty controls (TSA; tendon clinically unaffected).ResultsAcute tears to the rotator cuff were associated with an overall decrease in tendon metabolites. This global decrease was primarily associated with glycolic acid and decreased tricarboxylic acid (TCA) cycle activity. Conversely, chronic tendon specimens from patients undergoing rTSA showed an overall increase in metabolites. Most notably, chronic injury was associated with increased levels of multiple amino acids including alanine, aspartate, lysine, and proline.ConclusionsOverall, this study demonstrates that distinct metabolite profiles are associated with injury types, and that therapeutic strategies should address both cellular and matrix components regardless of injury induction. The specific pathways identified paired with validated, established, treatment methods may serve as novel therapeutic targets for patients who suffer from rotator cuff injuries.

BackgroundLow load exercise training with blood flow restriction (BFR) has become increasingly used by human physical therapists to prescribe controlled exercise following orthopaedic injury; its effects on the equine superficial digital flexor tendon (SDFT), however, are unknown.ObjectiveTo investigate outcomes of pressure specific BFR walking exercise on uninjured equine SDFT biomechanics and histomorphology.Study designControlled in vivo experiment.MethodsFour forelimbs of four horses were exposed to 40 BFR-walk sessions (10-min interval walking) on a treadmill over a 56-day study period with their contralateral forelimbs serving as untreated controls. Similarly, four forelimbs of four control horses were exposed to 40 sham cuff walk sessions. On study Day 56, all horses (n = 8) were humanely euthanised and forelimb SDFTs underwent non-destructive biomechanical testing and corresponding histomorphological analysis. Significance in biomechanical parameters between treatment groups was analysed using a mixed-effects ANOVA with Tukey's post-hoc tests.ResultsStatistically significant differences in SDFT stiffness for both first (p = 0.02) and last cycles (p = 0.03) were appreciated within the BFR treated group only, with BFR exposed forelimbs being significantly stiffer than the contralateral unexposed forelimbs. When normalised to cross-sectional area, no significant differences were appreciated among treatment groups in elastic modulus for the first (p = 0.5) or last cycles (p = 0.4). No histological differences were appreciated among treatment groups according to Bonar, Movin, or musculotendinous junction evaluation criteria.Main limitationsShort-term comparisons were performed in a small sample population without correlation to performance outcome measures. Optimal occlusion percentages and walk protocols remain unknown.ConclusionsThis study demonstrated no negative impact of BFR on mechanical strength of the equine SDFT; however, evidence suggests that BFR results in increased tendon stiffness based on biomechanical testing and subsequent calculations. No consistent detrimental histomorphological changes were seen. ContextoExerc & iacute;cio de baixa carga com restri & ccedil;& atilde;o do fluxo sangu & iacute;neo (RFS) tem sido cada vez mais utilizado por fisioterapeutas humanos para tratar les & otilde;es ortop & eacute;dicas. Por & eacute;m, seus efeitos no tend & atilde;o flexor digital superficial (TFDS) de equinos n & atilde;o & eacute; conhecida.ObjetivosO objetivo deste estudo foi investigar o efeito de espec & iacute;ficas press & otilde;es com RFS durante o passo em cavalos sem les & atilde;o no TFDS, por meio de histologia e an & aacute;lise biomec & acirc;nica.Delineamento do estudoEstudo controlado.M & eacute;todosQuatro membros tor & aacute;cicos de quatro cavalos foram expostos a 40 sess & otilde;es de RFS durante o passo (10 minutos de caminhada intervalada), ao longo de 56 dias. O membro contralateral foi utilizado como controle. Da mesma forma, quatro membros de quatro cavalos controle foram expostos a 40 sess & otilde;es simuladas de caminhada com torniquete. No dia 56, todos os cavalos (n = 8) foram eutanasiados, e os TFDS foram submetidos a testes biomec & acirc;nicos n & atilde;o destrutivos e an & aacute;lise histol & oacute;gica. A signific & acirc;ncia dos par & acirc;metros biomec & acirc;nicos entre tratamentos foi analisada utilizando ANOVA de efeitos mistos, seguida pelo teste de Tukey.ResultadosA rigidez do TFDS foi estatisticamente diferente nos primeiros (p = 0.02) e & uacute;ltimos (p = 0.03) ciclos no grupo submetido & agrave; RFS, sendo os membros tratados significativamente mais r & iacute;gidos do que os membros contralaterais n & atilde;o expostos ao tratamento. Quando normalizado para a & aacute;rea transversal, n & atilde;o foi observada diferen & ccedil;a significativa entre os grupos de tratamento no m & oacute;dulo de elasticidade para os primeiros (p = 0.5) e & uacute;ltimos (p = 0.4) ciclos. N & atilde;o foram identificadas diferen & ccedil;as histol & oacute;gicas nos diferentes tipos de tratamento, de acordo com os crit & eacute;rios de avalia & ccedil;& atilde;o Bonar, Movin e de jun & ccedil;& atilde;o musculo-tend & iacute;nea.Principais limita & ccedil;& otilde;esCompara & ccedil;& otilde;es de curto prazo foram realizadas em uma amostra pequena da popula & ccedil;& atilde;o, sem correla & ccedil;& atilde;o com medidas de resultados de desempenho. As porcentagens ideais de oclus & atilde;o e os protocolos de caminhada permanecem desconhecidos.Conclus & otilde;esEste estudo n & atilde;o demonstrou impacto negativo do RFS na resist & ecirc;ncia mec & acirc;nica do TFDS equino; no entanto, as evid & ecirc;ncias sugerem que a RFS resulta em aumento da rigidez do tend & atilde;o com base em testes biomec & acirc;nicos e c & aacute;lculos subsequentes. Nenhuma altera & ccedil;& atilde;o histol & oacute;gica prejudicial consistente foi observada.

Objective: To compare the safety and short-term clinical effect of three serum types [equine serum (ES), 'equine interleukin-1 receptor antagonist protein' serum (eq-IRAP), and canine IRAP serum (ca-IRAP)] on keratoconjunctivitis sicca (KCS) in dogs.Animals Studied: Three research dogs diagnosed with spontaneous KCS.Procedures: Each dog was treated for three days, three times a day (TID) in both eyes (OU) with ES, followed by three days of treatment with eq-IRAP TID OU, followed by three days treatment with ca-IRAP TID OU.Clinical parameters (discharge, conjunctival hyperemia, chemosis) were scored on the last treatment day for each serum type.Schirmer tear test (STT) was measured throughout the study.The three different serum types were analyzed with ELISA kits for the concentration of equine interleukin-1 receptor antagonist (eq-IL-1Ra), and ca-IL-1Ra.Results: All three serum types were well tolerated in the three dogs.Subjectively, dogs treated with ca-IRAP showed improved clinical parameters such as decreased conjunctival hyperemia.Objectively, no differences in STT were seen between the groups (P > 0.05).The highest concentration of IRAP was found in ca-IRAP analyzed for ca-IL-1Ra (299.7 pg/mL). Conclusion:Topical ca-IRAP was noted to have the most significant clinical effect on evaluated parameters.Future long-term studies are needed to confirm the potential anti-inflammatory effect of topical ca-IRAP.approved in the United States for the treatment of rheumatoid ar-

Damage to the soft tissue structures of the digit is a common source of equine lameness. While magnetic resonance imaging (MRI) allows for the most complete diagnostic imaging of the equine digit, ultrasound is more readily available and less expensive. This prospective diagnostic accuracy study compares ultrasound to MRI for the diagnosis of injuries visible with ultrasound within the digit, including the deep digital flexor tendon (DDFT), collateral sesamoidean ligament (CSL), and navicular bursa. Clinical patients underwent an MRI of the digit and a blinded ultrasound of the digit between the heel bulbs, and results of the two modalities were compared. A total of 70 ultrasound and MRI exams of 45 horses were included. Ultrasound had good sensitivity (85%), moderate specificity (60%), and accuracy of 70% for evaluating the dorsal tearing of the DDFT. Accuracy was lower for navicular bursa effusion (67%), navicular bursa proliferation (61%), and CSL enlargement (61%). Tearing of the DDFT distal to the navicular bone was identified with MRI in 27 limbs, 20 of which also had dorsal damage proximal to the navicular bone identified with ultrasound. Ultrasound evaluation remains a useful screening tool, particularly for the assessment of DDFT tearing proximal to the navicular bone but risks under-diagnosing pathology to the navicular bursa and CSL. Clinically significant concurrent damage to the distal DDFT and other osseous and soft tissues in the hoof capsule is unlikely to be identified without MRI.

Background Comparison of radiography to magnetic resonance imaging (MRI) can help objectively assess the value and limitations of radiographs in orthopaedic disease processes. The tarsus and proximal suspensory origin of the metatarsus are commonly imaged regions for lameness. The knowledge gained by comparison between imaging modalities will aid in improving accuracy of radiographic interpretation. Objective To compare the radiographic and MRI findings of the proximal third metatarsal bone (MTIII) and proximal suspensory ligament using MRI as the gold standard. Study design Retrospective observational study. Methods Single hindlimbs of 35 horses with radiographic and high-field (3Tesla (3T)) MRI studies were blindly evaluated by two board-certified veterinary radiologists and a radiology resident. Severity and location of the following parameters were assessed: radiographic MTIII sclerosis and lucent regions, MRI endosteal metatarsal sclerosis and bone marrow lesions, plantar cortical proliferation and resorption, and proximal suspensory desmopathy (PSD). Results Radiographic osseous changes of MTIII were identified in 54% of limbs, whereas 40% limbs had osseous changes on MRI: 43% of limbs had PSD on MRI. No significant association was found between the presence of radiographic changes in MTIII and PSD on MRI (P = .7). A statistically significant association and positive correlation was found between the severity of radiographic changes and MTIII plantar cortical proliferation and resorption on MRI (P = .01). Main limitations Retrospective study with no histopathology. Ability to correlate findings with lameness was limited by the lack of standardised time intervals between onset of lameness, diagnostic analgesia and advanced imaging. Conclusion Radiographic bony changes of proximal MTIII do not reliably predict presence or severity of PSD but are associated with osseous changes at the proximal MTIII. The presence of radiographic changes should warrant additional diagnostics in the region prior to making conclusions about the presence or absence of PSD.

We report the relationships between linear vs. network polymer architecture and biomechanical outcomes including lubrication and cushioning when the polymers are applied to the surface of articulating knee cartilage. Aqueous formulations of the bioinspired polymer poly(2-methacryloyloxylethyl phosphorylcholine) (pMPC) exhibit tuneable rheological properties, with network pMPC exhibiting increased elasticity and viscosity compared to linear pMPC. Application of a polymer network, compared to a linear one, to articulating tissue surfaces reduces friction, lessens tissue strain, minimizes wear, and protects tissue - thereby improving overall tissue performance. Administration of the network pMPC to the middle carpal joint of skeletally mature horses elicits a safe response similar to saline as monitored over a 70 day period.

Over the past three decades, electrohydraulic extracorporeal shock wave therapy (ESWT) as a treatment modality for equine orthopaedic disorders has sparked exponential interest among practitioners, but its clinical applications are quickly evolving and a current review highlighting modernised equine clinical use is lacking. The objective of this review is to summarise the most current ESWT technology, evidence for its use, proposed mechanisms of action and clinical applications in horses while also highlighting the areas requiring further investigation. The three ways to generate a shock wave are through electrohydraulic, electromagnetic or piezoelectric mechanisms, but over the last decade, electrohydraulic systems have predominated due to the ability to focus and control a therapeutic waveform. Shock waves' primary physical effect is believed to be via mechanotransduction leading to cellular activation and downstream signalling. Experimentally, ESWT's effects on osseous, connective tissue and wound healing via various mechanisms of action have been reported both in the human and veterinary literature. Clinical trials have investigated ESWT's orthopaedic application including osteoarthritis, thoracolumbar pain, navicular syndrome, tendinopathy and proximal suspensory desmopathy, with its concomitant use with biologics representing an area of active research. Direct ESWT protocol comparisons in terms of long-term efficacy with variables of energy, depth and exposed tissue types are still lacking with evidence-based recommendations being largely anecdotal. Technical advancements to facilitate the safe and judicious use of ESWT include human and equine hearing protection, light sedation and/or patient restraint. Efforts to ensure the safe and judicious use of ESWT and its analgesic effects are ongoing.

OBJECTIVE:To advance the understanding of how alterations in exercise speed and grade (flat vs 17° incline or decline) affect the quality of tendon healing, and to determine if a biomarker relationship exists between serum levels of a ColX breakdown product (CXM) and animals exposed to treadmill running protocols.ANIMALS:35 male mice (C57BL/6J), 8 weeks of age.PROCEDURES:Mice were preconditioned on a treadmill for 14 days. Tendinopathy was then induced by 2 intra-tendinous TGFβ1 injections followed by randomization into 7 exercise groups. Exercise capacity and objective gait analysis were measured weekly. Mice were euthanized and histopathologic analysis and evaluation of serum CXM levels were performed. Statistics were conducted using a 2-way ANOVA (exercise capacity), Mixed Effects Model (gait analysis, effect of preconditioning), and 1-way ANOVA (gait analysis, the effect of injury, and rehabilitation normalized to baseline; CXM serum analysis), all with Tukey post hoc tests and significance set to P < .05.RESULTS:Exercise at a fast-flat speed demonstrated inferior tendinopathic healing at the cellular level and impaired stance braking abilities, which were compensated for by increased propulsion. Mice exposed to exercise (at any speed or grade) demonstrated higher systemic levels of CXM than those that were cage rested. However, no ColX immunostaining was observed in the Achilles tendon or calcaneal insertion.CLINICAL RELEVANCE:Exercise at a fast speed and in absence of eccentric loading components (incline or decline) demonstrated inferior tendinopathic healing at the cellular level and impaired braking abilities that were compensated for by increased propulsion.