Search

Background and Aim: A healthy joint is an important structure for the proper movement of the camel limb. Intra-articular (IA) injection is frequently used in veterinary practice for diagnostic and therapeutic purposes of joint injuries. Thus, the current study aimed to describe the injection of the hindlimb joints in dromedary camels based on the anatomical and arthrographic-guided landmarks. Materials and Methods: Eighteen orthopedically sound adult camels (mean±standard deviation age: 78±12 months) of both sexes were included in this study. Three camels were euthanized to identify anatomical features in the hindlimb joints and related structures. IA injections were performed in the hindlimbs of 5 camel cadavers to evaluate the optimal IA injection site, which was confirmed by arthrography. The optimized IA injection technique was applied in 10 live camels and confirmed by arthrocentesis and arthrography. For each joint, injection criteria (number of attempts, difficulty of injection, and successful injection) were assessed, scored, and statistically compared to the other joints. Results: The summation of IA injection criteria scores was significantly higher (p

Post-traumatic osteoarthritis is a disabling condition impacting the mostly young and active population. In the present study, we investigated the impact of intra-articular sprifermin, a recombinant truncated fibroblast growth factor 18, on the outcome of microfracture treatment, a widely used surgical technique to enhance cartilage healing at the site of injury. For this study, we created a cartilage defect and performed microfracture treatment in fetlock joints of 18 horses, treated joints with one of three doses of sprifermin (10, 30, or 100 μg) or with saline, hyaluronan (HA), and evaluated animals functional and structural outcomes over 24 weeks. For primary outcome measures, we performed histological evaluations and gene expression analysis of aggrecan, collagen types I and II, and cartilage oligomeric matrix protein (COMP) in three regions of interest. As secondary outcome measures, we examined animals' lameness, performed arthroscopic, radiographic, and CT scan imaging and gross morphology assessment. We detected the highest treatment benefit following 100 μg sprifermin treatment. The overall histological assessment showed an improvement in the kissing region, and the expression of constitutive genes showed a concentration-dependent enhancement, especially in the peri-lesion area. We detected a significant improvement in lameness scores, arthroscopic evaluations, radiography, and CT scans following sprifermin treatment when results from three dose-treatment groups were combined. Our results demonstrated, for the first time, an enhancement on microfracture outcomes following sprifermin treatment suggesting a cartilage regenerative role and a potential benefit of sprifermin treatment in early cartilage injuries. This article is protected by copyright. All rights reserved.

A five-day-old Holstein Friesian male calf was presented for the evaluation of severe fetlock flexural deformities with a large pressure ulcer over the right metacarpal bone. Superficial and deep digital flexor tenotomy was performed. The surgical wound recovered well, but 15 days after surgery, the skin over the pressure ulcer was starting to fall away and exposing tendon and muscle. A hoof toe-extension shoe was applied to decrease pressure on the wound. The wound had a moderate bacterial infection and slowly responded to cleansing twice a day with 0.9% normal saline, 10% povidone iodine and a topical antibiotic. Topical autologous platelet-rich plasma (PRP) was then applied to the lesion ([Formula: see text][Formula: see text]cm) twice. The wound showed rapid tissue regeneration, good quality wound healing and no complications. After PRP treatment, the lesion size decreased ([Formula: see text][Formula: see text]cm). At this point, 0.9% normal saline cleansing and a bandage were applied until the wound had completely healed. This case report suggests that the hoof toe-extension shoe and topical dressing with autologous PRP, as a combination treatment, could be effective for fetlock flexural deformities with skin defects or delayed wound healing in large animals.

Background Transverse stress fracture of the palmar cortex of the distal aspect of the third metacarpal bone (TSF PCD McIII) is poorly documented. Objectives To describe the typical signalment of this injury, the common clinical and radiological signs and prognosis. Study design A retrospective hospital-based case series with follow-up of racing records. Methods All cases of TSF PCD McIII diagnosed among racehorses in training at the Hong Kong Jockey Club between 2011 and 2019 were identified. Clinical records were reviewed and documented signs were recorded for each case. Findings from a predefined list of radiological features were listed. Descriptive statistics were used to describe the age and training profile of horses, the clinical and radiological findings and time to return to ridden exercise. Results Twenty-three cases (n = 23) were identified. The majority (57%) had recently started or returned to training from a break and 35% (n = 8) of cases had not yet undertaken timed gallops at the time of injury. Most cases (20/23; 87%) were lame; in nine (39%), lameness was severe. Localised swelling of superficial soft tissues was reported in 15/23 (65%) cases. Pain on palpation of the distal McIII was present in 15/23 (65%) cases and in response to fetlock flexion in 12/23 (52%). Diffuse, localised increase in radiopacity, disruption to the outline of the bone periosteal surface and outward displacement of the button of the splint bone were common radiological features in early cases (70%, 67% and 67% of all cases). Sixty-one per cent of cases (14/23) were initially misdiagnosed. Most horses (n = 18/23) resumed training and racing after a median of 83 and 246 days. Main limitations Clinical notes were not consistent between cases. Radiographs were taken at different times. Conclusions Horses commencing training are at risk of TSF PCD McIII, which presents with confusing clinical signs and subtle radiological findings. The long-term outlook is favourable.

BACKGROUND Subchondral bone pathology is common in Thoroughbred racehorses and believed to precede more serious injury. Early identification of pathology is critical to allow for intervention. OBJECTIVES To determine interobserver variability of fetlock subchondral bone lesions using cone beam and fan beam computed tomography (CBCT, FBCT) and to validate a robotics-controlled CBCT to identify fetlock subchondral bone pathology in the Thoroughbred racehorse. STUDY DESIGN Prospective cohort study. METHODS FBCT and CBCT images were acquired of 25 metacarpo-/metatarsophalangeal joints of Thoroughbred racehorses. Images were analysed for subchondral bone lesions commonly identified in Thoroughbred fetlocks by an imaging specialist and surgery specialist. Interobserver and intermodality equivalence were determined with a Pearson correlation analysis and Bland-Altman equivalence test. RESULTS Interobserver FBCT correlation was significant (P

This study was designed to evaluate and compare the optimal sites for intra-articular (IA) injection into the digits of buffalo by discrimination of the injection criteria. Forty-eight cadaveric hind digits of adult buffalos and nine live ones were assigned for three trial investigations. In the first division, eighteen sound cadaveric limbs were used to describe the anatomical features of the hind digit. In the second division, thirty cadaveric limbs (ten for each approach) were injected with an equal volume of iopamidol through relevant joint pouches to compare the dorsal, lateral and plantar IA approaches for each joint. The former technique was applied to nine live, healthy adult buffaloes to evaluate the accuracy of IA injection of the hind digit in vivo. Injection criteria were assessed, scored and statistically compared among the three approaches. The summation of injection criteria scores showed a significant increase (P < 0.05) in the dorsal and lateral approaches for IA injection of the fetlock, pastern and coffin joints in the buffalo digit compared to the plantar one. However, median and range of injection criteria scores between the dorsal and lateral approaches were slightly less significant. In conclusion, the present study established a reference for IA injection of the buffalo digit that could aid the diagnosis and treatment of digit-related lameness.

Background: There is a paucity of research describing the gait pattern of lame horses at the walk. Objectives: To describe the changes in motion pattern and vertical ground reaction forces (GRFz) in horses with induced forelimb lameness at the walk and compare those changes with the changes observed at the trot. Study design: Experimental study. Methods: In 10 clinically sound Warmblood horses, moderate forelimb lameness was induced using a sole pressure model followed by trot and walk on a treadmill. Kinematic data were collected using 3D optical motion capture (OMC), and GRFz by an instrumented treadmill. Mixed models were used to compare sound baseline versus forelimb lameness (significance was set at P

BACKGROUND Arthroscopy has been advocated as the treatment of choice for dorsal osteochondral chip fracture of the metacarpo/metatarsophalangeal (MCP/MTP) joint. However, there is no published research on racing performance outcomes of horses with this pathology managed nonsurgically. OBJECTIVES To compare racing career outcomes of Thoroughbred racehorses with nonsurgically (non-SX) or surgically (SX) managed MCP/MTP dorsal osteochondral chip fracture alongside a cohort of horses with no dorsal osteochondral chip fracture (unexposed). STUDY DESIGN Retrospective cohort study conducted between 2006 and 2014. METHODS Radiographs of Thoroughbred racehorses were reviewed to identify MCP/MTP dorsal osteochondral chip fractures. Unexposed horses under the care of the same practice were recruited randomly from training records. Racing outcomes were analysed using survival analysis and logistic, linear and negative binomial regression techniques. RESULTS Dorsal osteochondral chip fractures were identified in 98 (70 non-SX, 28 SX) horses and compared with 648 unexposed horses. There was no significant difference among non-SX, SX, and unexposed horses in respect of total career starts, or likelihood of ever winning, placing, or earning money in a race (P > .05). SX horses had a significantly higher rate of wins/start than non-SX horses (rate ratio 1.6, CI 1.1-2.4, P = .02) and unexposed horses (rate ratio 1.9, CI 1.3-2.8, P = .001). Total career earnings for the SX horses were 4.1 times that of the unexposed horses (95% CI 1.2-14.5, P = .03), although total career earnings did not differ significantly between non-SX and unexposed horses (P = .8). MAIN LIMITATIONS Retrospective observational study where management technique was not randomised or blinded. Small number of surgically managed horses and potential selection bias for surgical management. CONCLUSIONS Nonsurgical management of this injury appears to be a valid management choice given that it was not associated with significant effects on racing career performance relative to a large unexposed cohort in this study population.

BACKGROUND Pathology involving the oblique sesamoidean ligaments (OSLs) is commonly diagnosed during magnetic resonance imaging (MRI) of the equine distal limb. Presence of striations within the ligament and magic angle artefact can result in an incorrect diagnosis of pathological change. No studies have been performed using histopathology, the gold standard, to corroborate their imaging diagnosis. OBJECTIVES (a) To determine which MRI characteristics are associated with normal vs abnormal OSLs and (b) to evaluate the ability of MRI to correctly identify abnormal vs normal oblique sesamoidean ligaments using histopathology as the gold standard. STUDY DESIGN Observational, cross-sectional study. METHODS Cadaver limbs (n = 77) were obtained from horses (n = 21) subjected to euthanasia at the hospital. MRI and histopathology was performed on each of the limbs. MRI scoring was performed for multiple MRI characteristics, and each limb was deemed normal or abnormal. Histopathology scoring was performed to give an overall score of normal or abnormal. Mixed model logistic regression was performed to evaluate which MRI characteristics were associated with normal vs abnormal OSLs using backwards elimination and a significance level of

Habronemiasis is characterized by proliferative moist and granulomatous wounds mostly affecting medial canthus, shoulders, knees, fetlock, abdominal wall and prepuce of donkeys. It is caused by invasion of Habronema species larvae in moist skin tissues and wounds. Surgical removal of granulation tissue, topical or systemic use of corticosteroids and ivermectin are used to treat the clinical cases, however, satisfactory treatment of the cases of habronemiasis associated with proud flesh in donkeys is difficult. In present study, clinical cases of habronemiasis in donkeys were treated successfully using an extract prepared from the leaves of Aerva javanica.

Objective: To describe the MRI findings for 13 horses with deep digital flexor tendon (DDFT) injury at the proximal phalanx where the tendon goes from ovoid to bilobed in frontlimbs with tendon sheath distension. In addition, the prognosis of this lesion was assessed.Design: Retrospective case series.Animals: Thirteen client-owned horses.Procedures: Medical records were reviewed, and data were collected regarding signalment, history, MRI findings, and outcomes of horses. Findings of MRI were recorded and whether the case was confirmed with tenoscopy.Results: A diagnosis of DDFT injury at the junction between ovoid and bilobed portions at the level of the proximal phalanx was established in 13/20 (65%) horses that underwent MRI examination of the frontlimb digital flexor tendon sheath. Return to previous level of work was poor in this subset of horses with only three of 13 (23%) horses returning to previous level of work and one horse still in rehabilitation.Conclusions and Clinical Relevance: Standing low-field MRI represents a potentially useful diagnostic tool to evaluate digital flexor tendon sheath distension especially when evaluating the DDFT at the proximal phalanx where the tendon progresses from ovoid to bilobed. Prognosis of lesions of the DDFT at the proximal phalanx appears less favorable than previously reported causes of tendon sheath distension.

Simple Summary Early detection of racehorses at risk of stress fracture is key to reducing the number of horses with catastrophic fractures while racing. Bone changes are often visible in the limbs of Thoroughbred racehorses in work, particularly in the fetlock region. However, it is currently unknown whether some of these changes indicate an impending fracture or are a healthy adaptation to high-speed exercise. This study looks at imaging and gross changes in a specific area (parasagittal grooves (PSGs) of the cannon bone) and the utility of X-ray, computed tomography (CT) and magnetic resonance imaging (MRI) to detect the changes. All fetlock joints were assessed from twenty horses that died during racing or training, including horses with and without fetlock fracture. Overall, X-ray was poor for detecting PSG changes. Some PSG changes on CT and MRI were common in Thoroughbred racehorses and possibly represent normal bone adaptation when seen in clinical cases. However, certain CT and MRI findings were more prevalent in horses with a fracture, possibly indicating microdamage accumulation and increased risk of fracture. Bilateral advanced imaging is recommended in clinical cases of suspected fetlock pathology. Abstract (1) Background: Parasagittal groove (PSG) changes are often present on advanced imaging of racing Thoroughbred fetlocks and have been suggested to indicate increased fracture risk. Currently, there is limited evidence differentiating the imaging appearance of prodromal changes in horses at risk of fracture from horses with normal adaptive modelling in response to galloping. This study aims to investigate imaging and gross PSG findings in racing Thoroughbreds and the comparative utility of different imaging modalities to detect PSG changes. (2) Methods: Cadaver limbs were collected from twenty deceased racing/training Thoroughbreds. All fetlocks of each horse were examined with radiography, low-field magnetic resonance imaging (MRI), computed tomography (CT), contrast arthrography and gross pathology. (3) Results: Horses with fetlock fracture were more likely to have lateromedial PSG sclerosis asymmetry and/or lateral PSG lysis. PSG lysis was not readily detected using MRI. PSG subchondral bone defects were difficult to differentiate from cartilage defects on MRI and were not associated with fractures. The clinical relevance of PSG STIR hyperintensity remains unclear. Overall, radiography was poor for detecting PSG changes. (4) Conclusions: Some PSG changes in Thoroughbred racehorses are common; however, certain findings are more prevalent in horses with fractures, possibly indicating microdamage accumulation. Bilateral advanced imaging is recommended in racehorses with suspected fetlock pathology.

Background: Swimming is used for rehabilitation and conditioning purposes in equine sports medicine despite the lack of understanding of equine swimming kinematics. The aim of this study was to assess forelimb joints kinematics (elbow, carpus, and fetlock) in swimming horses. The specific objectives were 1- to calculate and compare joint angles in swimming vs. passive mobilizations (PM), 2- to determine joint angular velocities during a swimming stride cycle.Methods: Eleven elite endurance horses swam in a 100-m straight pool. Underwater (swimming) and overground (PM) videos were recorded from the horses' left side. Joint markers were applied on the lateral hoof wall, lateral metacarpal epicondyle, ulnar carpal bone, lateral humeral epicondyle, and the greater tubercle of humerus, from which elbow, carpus and fetlock angles, and angular velocities were obtained. As a reference, maximal fetlock, carpus, and elbow flexion/extension angles were determined during PM overground. Differences between angle extrema, angular velocities and range of motion (ROM) were compared.Results: Carpus and fetlock ROM were significantly smaller (p < 0.001) during swimming when compared with PM, while there was no difference in elbow ROM between both situations. The carpus had the greatest ROM of all joints during swimming. Absolute angular velocities values of all joints during swimming were greater during retraction than protraction (p < 0.001). When compared to other joints during protraction, the carpus joint reached the highest angular velocity.Conclusion: Swimming, as a rehabilitation exercise, has the potential to benefit horses where great elbow ROM with a moderate carpus and fetlock extension are wanted.

A horse with an open medial luxation of the left metatarsophalangeal joint with extensive cartilage and soft tissue damage and severe contamination of the wound was treated with a two-stage approach. In the first stage, the lesion was cleaned, the luxation was reduced, the wound was sutured and the limb was kept in a cast for a total time of 56 days. In the second stage, an arthrodesis of the affected joint was carried out, using a 13-hole broad 4.5 LCP plate. The limb was then kept in a cast for an additional total time of 56 days. At 70 days after the arthrodesis, the horse was brought in for a final check-up, and only a mechanical lameness remained at that time. No significant complications occurred. Previous case reports on the treatment of metatarso-/metacarpophalangeal luxations include neither cases as severe as the one presented here nor treatment by fetlock arthrodesis. This case illustrates that horses with a complicated, open luxation of the fetlock can be salvaged for breeding purposes.

Consumption of β-hydroxy β-methylbutyrate (HMB) alters muscle composition and metabolism leading to strength and agility improvements in human athletes. To determine if HMB affects athletic performance and muscle function in horses, Thoroughbred geldings were fed a control (CON; n = 5) or HMB (n = 6) supplement for 6 wk prior to completing a standardized exercise test (SET). Gluteus medius (GM) muscle biopsies were obtained before the SET for fiber typing. Heart rate, biceps femoris (BF) and semitendinosus (ST) surface electromyograms (EMG), and fore and hind limbs metacarpophalangeal joint angles were captured at the gallop of the SET. Results demonstrate that HMB supplementation increased (P < 0.05) the percentage of type IIA and IIA/X muscle fibers in the GM with a corresponding decrease (P < 0.05) in type IIX fibers. The percentage of type I fibers was unaffected by diet. Supplementation with HMB did not result in any measurable effects on performance or biomechanical properties by comparison to CON. Supplementation with HMB resulted in an increase (P < 0.05) in ST median frequency at speeds of 10 m/s and greater. Increasing treadmill speed resulted in an increase (P < 0.05) in stride length and the maximal proximal forelimb fetlock angle, and a decrease (P < 0.05) in stance phase time of the gait cycle. Integrated EMG (iEMG) increased (P < 0.05) with increasing treadmill speeds for both the BF and ST with the BF exhibiting greater (P < 0.05) iEMG values than the ST. In summary, HMB increased the percentage of type IIA GM fibers, which did not translate into improved performance.

The current study aimed to describe the normal cross-sectional anatomy, magnetic resonance imaging, and computed tomography of the fetlock joint in adult healthy dromedary camel. This study was carried out on twelve fetlock joints of the fresh cadavers from three camels. The gross examination of these camels revealed that they were normal with no orthopedic abnormalities. The cadaveric fetlock joints (n=12) were scanned using a computed tomographic (CT) scanner and a 1 Tesla MRI scanner. Then the joints were injected with a colored latex and sectioned into transverse, dorsal, and sagittal slices. Cross-anatomical sections were correlated with their corresponding CT and MR images for evaluation of the normal relevant anatomical structures that appeared with different signal intensities on the CT and MRI scans. The current investigation revealed that all the major soft tissue structures in the fetlock joint of the dromedary camel were clearly visualized on both CT and MR scans, except the short and the cruciate sesamoidean ligaments that could not be identified on both the CT and MR images. The anatomical sections with their corresponding CT and MR images obtained in this study could be used as a reference for subsequent clinical diagnosis and the interpretation of fetlock joint pathologies in dromedary camel.

Intra-articular (IA) hyaluronic acid (HA) is commonly used to treat equine arthritis. Inflammatory response or "joint flare" is a recognized potential side effect. However, the incidence and severity of inflammation following IA HA injection in horses is not well documented. This study compared the effects of two IA HA formulations of different molecular weight (MW) and a saline control on clinical signs and synovial fluid markers of inflammation in normal equine joints. Eight adult horses each had three healthy fetlock joints randomly assigned to treatment with either 1.4 mega Dalton HA, 0.8 mega Dalton HA or saline control once weekly for three weeks. Clinical evaluation and synovial fluid analysis were performed by blinded assessors. Outcomes of interest were lameness score, joint effusion score and synovial fluid white cell count and differential, total protein, viscosity and serum amyloid A. Joints injected with HA developed significant mild-to-moderate inflammatory responses often associated with lameness and joint effusion compared with saline control joints. The higher MW HA formulation elicited a significantly greater inflammatory response than the lower MW HA after the first injection. In HA injected joints, viscosity remained poor for the entire study. Both IA HA formulations in this study induced an inflammatory response in healthy equine joints. This may have implications for the use of HA in equine joints. The findings in this study are limited to the two HA formulations used. Further investigation of different HA formulations and the use of HA in normal and arthritic equine joints is warranted.

INTRODUCTION Several young bulls in a beef farm showed large, foul-smelling skin lesions in the plantar region of the coronary band and in the interdigital space. Some of the animals also had a painful, warm swelling in the palmar fetlock area. All bulls were lame (score 4/5), the most severely affected animal had a lameness score of 5/5. Initial local treatment was unsuccessful, therefore the animals received parenteral antimicrobial treatment leading to improvement of clinical signs and weight bearing in most animals. However, several animals were slaughtered prematurely due to severe foot lesions. The diverse clinical picture did not allow for diagnosing one specific claw affection without further diagnostic investigations. Histopathological and bacteriological examinations confirmed the diagnosis of digital dermatitis (DD) in combination with an interdigital phlegmon, whereby five of the seven examined specimens were positive for one or more Treponema spp. Treponemes belong to the spirochetes, the ones commonly involved in DD in dairy cows include Treponema medium, Treponema phagedenis and Treponema pedis. The last two species were detected in the present cases. The clinical findings and results of diagnostic investigations indicate that a severe form of DD complicated by a secondary infection and interdigital phlegmon caused an outbreak of severe lameness in young bulls in a beef farm. Single or combined claw diseases can be associated with severe losses not only in dairy but also in beef herds.

INTRODUCTION The clinical, ultrasonographic, radiographic, cytologic and bacteriologic findings, diagnosis and surgical treatment of two heifers with septic metacarpal physitis (type-1 osteomyelitis) and concurrent serofibrinous arthritis of the metacarpophalangeal (MCP) joint are described. Osteomyelitis likely occurred by haematogenous spread following bronchopneumonia in one heifer and developed post-traumatically in the other. In both patients, ultrasonographic examination using the 7.5 MHz linear probe showed moderate effusion of the palmar and dorsal MCP joint pouches and highly irre-gular bone contours with depression and periosteal new bone formation at the metacarpal growth plate. Radiographs showed an extensive radiolucent area with poorly defined margins at the level of the metacarpal growth plate. Surgical treatment was carried out under sedation and regional intravenous anesthesia and involved meticulous debridement of the osteomyelitic lesion of the meta-carpal growth plate combined with arthrotomy of the MCP joint and repeated lavage of the bone cavity and joint. Successful outcomes were achieved by combined use of systemic and locoregional antibiotics, NSAIDs, temporary external coaptation and adequate housing.

Objective To describe the history, clinical signs, and management of six horses in which subtendinous bursitis of the long digital extensor tendon (LDET) in the hind limb fetlock had been diagnosed. Study design Retrospective case series. Sample population Six privately owned horses. Methods The medical records of horses presented at the hospital with similar sypmtoms were evaluated and collected. Finally 6 horses met the inclusion criteria and the relevant data were compiled and analysed. In three of the six cases a surgical treatment was carried out. Results All horses had similar clinical signs, mainly distention beneath the long digital extensor tendon (LDET) at the level of the hind limb fetlock without associated lameness; the major issues were the presence of cosmetic defects and concern about their functional use in the future. Three of the six horses were treated surgically with bursoscopic debridement. The cosmetic results were excellent in two of these three horses. One horse that underwent an operation experienced a recurrence. None of the horses with bursitis treated medically experienced resolution of the problem. Conclusion Bursoscopy is a technique to consider for the management of bursitis of the LDET at the level of the fetlock combined with prolonged bandage application when medical treatment has failed to manage the condition. Clinical significance To the best of our knowledge, subtendinous bursitis of the LDET in the hind limb is not a commonly diagnosed condition. This small case series provides some insight into methods for the clinical management of this issue.

Osteoarthritis is a significant and costly cause of pain for both humans and horses. The horse has been identified as a suitable model for human osteoarthritis. Regenerative therapy with allogeneic mesenchymal stem cells (MSCs) is a promising treatment, but the safety of this procedure continues to be debated. The aim of this study is to evaluate the safety of intra-articular injections of allogeneic MSCs on healthy joints by comparing two different dosages and two different tissue sources, namely, bone marrow and umbilical cord blood, with a placebo treatment on the same individuals. We also assessed the influence of autologous versus allogeneic cells for bone marrow-derived MSC treatment. Twelve clinically sound horses were subjected to injections in their 4 fetlock joints. Each of the three fetlocks was administered a different MSC type, and the remaining fetlock was injected with phosphate-buffered saline as a control. Six horses received 10 million cells per joint, and the 6 other horses received 20 million cells per joint. Clinical and ultrasound monitoring revealed that allogeneic bone marrow-derived MSCs induced significantly more synovial effusion compared to umbilical cord blood-derived MSCs but no significant difference was noted within the synovial fluid parameters. The administration of 10 million cells in horses triggered significantly more inflammatory signs than the administration of 20 million cells. Mesenchymal stem cell injections induced mild to moderate local inflammatory signs compared to the placebo, with individual variability in the sensitivity to the same line of MSCs. Understanding the behavior of stem cells when injected alone is a step towards the safer use of new strategies in stem cell therapy, where the use of either MSC secretome or MSCs combined with biomaterials could enhance their viability and metabolic activity.

OBJECTIVE To determine the prevalence of surgical site infection (SSI) after internal fixation and to identify risk factors for SSI and nonsurvival. STUDY DESIGN Retrospective study. ANIMALS One hundred fifty-five horses with long bone fractures or arthrodesis treated by internal fixation at 1 hospital between 2008-2016. METHODS Signalment, diagnosis, surgical repair, surgeon, surgical time, antimicrobial use, SSI onset, bacterial identification, and adjunct treatments were recorded. Perioperative variables were analyzed to identify risk factors associated with outcomes. RESULTS Surgical-site infection was reported in 22 of 155 (14.2%) horses, which is lower than what has been previously reported (P = .003). Horses with fetlock arthrodesis or ulnar fracture were more likely to develop SSI. Local prophylactic antimicrobial therapy was associated with an increased risk of SSI. Horses with SSI were 12 times (P

The present study was designed to provide a descriptive imaging database of the anatomic features of the digit of normal donkeys using ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) as a means to improve diagnosis and clinical decision-making regarding digit lameness in donkeys. Ten healthy donkeys with sound limbs were assigned for US examination of the digit in each forelimb. In addition, five donkey’s forelimb digit cadavers were subjected for CT and MRI examination. The donkey's digit was divided into three regions: fetlock, pastern, and foot. For evaluation of the digit, longitudinal and transverse US images were obtained. In CT evaluation, three plans were taken: axial, sagittal, and coronal. Whereas, in MRI evaluation, two plans were taken: axial and sagittal with two sequences, T1 and proton density. All US, CT, and MRI images of the donkey's digit were labeled and serially interpret using correlated anatomic cross-sections and references. There was a full description and proper differentiation of the anatomical features of the digit bony (distal third of cannon bone [MCIII], proximal sesamoid bones, phalanges, navicular bone, and digital cushion) and soft tissue structures (superficial digital flexor tendon, deep digital flexor tendon, suspensory ligament, intersesamoidean ligament, straight distal sesamoidean ligament, common digital extensor tendon, annular ligament, and fetlock joint capsule) on US, CT, and MRI images. In conclusion, US, CT, and MRI provide a useful noninvasive method for evaluation of the digit and give a well-defined baseline reference images for the donkey's digit for educational, research, and radiologic purposes.

BACKGROUND Osteochondral fragmentation of the proximal phalanx (DPP1 fragment) is a common finding in the racehorse. Whilst radiographic assessment has been reported to lack diagnostic sensitivity, ultrasonographic examination has been documented to be extremely sensitive for identification of bone fragments in the metacarpophalangeal joint. OBJECTIVES To determine the sensitivity and specificity of ultrasonography as an imaging modality for diagnosis of DPP1 fragmentation and to compare it with radiography in the Thoroughbred racehorse. STUDY DESIGN Retrospective cohort study. METHODS Medical records (radiographs and ultrasonographic examinations) of 56 Thoroughbred racehorses in training (average age 26.4 months [SD ±5.9]) with a history of forelimb fetlock joint effusion and arthroscopically confirmed DPP1 fragmentation were evaluated. Inter-observer agreement was calculated between three blinded reviewers for both ultrasonographic and radiographic findings. Median values were used for statistical analyses. Ultrasonographic and radiographic identification of DPP1 fragmentation was considered correct if in agreement with arthroscopic findings. The McNemar test was used to compare correct proportions between radiography and ultrasonography. Analyses were performed to evaluate correct identification of presence of fragment(s), location of fragment(s) and presence and location of fragment(s) within the joints, with values P

The most prevalent causes of death in racehorses are musculoskeletal injuries, causing ~83% of deaths within the racing industry in California and elsewhere. The vast majority of these injuries have preexisting lesions that predispose to fatal injury. A 4-y-old Thoroughbred colt suffered an acute suspensory apparatus failure, including biaxial proximal sesamoid bone fractures of the right front fetlock, causing loss of support of the fetlock joint and consequent fall with fractures of the cervical and sacral spine. Cervical fracture caused spinal cord damage that resulted in sudden death. A preexisting lesion in the medial proximal sesamoid bone likely predisposed to complete fracture of this bone and fetlock breakdown. Interestingly, a comparable osteopenic lesion was present in the intact medial proximal sesamoid bone of the left forelimb, which is consistent with bilateral repetitive overuse injury in racehorses. The morphologic features of the cervical and sacral spine fractures were compatible with acute injury; no evidence of preexisting lesions was seen. Most likely, these acute vertebral fractures occurred as a result of the horse falling. This case emphasizes the importance of performing a detailed autopsy in horses that suffer an appendicular musculoskeletal injury, particularly in fatal cases when the horse dies following a leg injury.

Articular degeneration can be characterized by fibrillation and eburnation of the articular layers of the metacarpophalangeal (MP) joint. Structural changes within the articular joint predispose the development of osteophytes, enthesophytes and, in many cases is associated with changes the collateral ligaments of the MP joint. The aim of the present study was to investigate the relationship between degenerative processes of the articular cartilage and the enthesopathies of collateral ligaments (superficial or deep portion) of the equine MP joint, using radiographic, ultrasonographic and anatomopathological exam, as well as establishing their sensitivity. Thirty equine forelimbs were selected from animals that died due to various clinical conditions with an average age of 5.7 years which came from a private clinic or sent to the Laboratory of Veterinary Pathology of UFSM. The specimens were placed in a hydraulic press and submitted to radiographic evaluation of the MP joint (lateromedial, flexed lateromedial, dorsopalmar, dorsolateral-palmaromedial oblique 450 and dorsomedial-palmarolateral oblique 450 projections). Transversal and longitudinal ultrasound images of the dorsal and collateral aspect of the MP joint were obtained using a Sonosite Edge machine with a 5 to 10 MHz linear transducer. Subsequently, the specimens were sent for gross and histopathological examination. A highly positive correlation (P value

Simple Summary Pressure boots are performance enhancing equipment used by showjumping horses. Showjumping is scored by knocked down obstacle rails and time. Similar to weighted boots, pressure boots are intended to improve the hindlimb retraction of jumping horses to reduce the likelihood of knocking down rails on course. Manufacturers describe pressure boots as using acupressure to improve a horse’s awareness of their own limbs. However, this mechanism has not been verified within the scientific literature. The size and shape of features on the interior boot surface suggest a mechanical mechanism may affect anatomical structures within the lower limb. This research aims to characterize the mechanical effect of pressure boots by measuring forces and joint angles of cadaveric limbs with and without a pressure boot applied. Cadaveric limbs with a pressure boot applied required greater compressive loads to flex the fetlock joint than limbs without a pressure boot applied. This difference in compressive loads increased with increasing fetlock flexion angle. Differences in limb compressive loads contributed to greater tensile loads of palmar tendons and ligaments, specifically the suspensory apparatus. Greater tensile loading of tendons and ligaments may increase the likelihood of musculoskeletal injury and warrant concern for animal welfare of equine showjumping athletes. Abstract Pressure boots are applied to hind limbs of showjumping horses with the intent to enhance jumping form. Manufacturers claim acupressure points enhance proprioception of hind limbs. With this increased awareness, horses are expected to retract their hind limbs to clear jump rails. This research aimed to investigate a more direct, mechanical effect of pressure boots on hind limb biomechanics. Cadaveric hind limbs (n = 6) were mechanically loaded in axial compression (3 cycles at 0.25 Hz, displacement control ~3300 N) with (2 trials) and without (2 trials) a pressure boot applied. During mechanical loading, fetlock angle was measured using bone fixed pins with retroreflective markers (30 Hz). Changes in limb load and fetlock angle between unloaded and loaded states, as well as average fetlock joint stiffness, were compared between trials with and without the pressure boot via ANOVA. Differences in measured loads between trials with and without the boot were observed in both unloaded (Δ = 6 N, p = 0.05) and loaded states (Δ = 25 N, p = 0.002). Trials with the boot had greater average fetlock stiffness (Δ = 3 N/degree, p = 0.001). Differences in loads with and without boots may increase with greater fetlock angles when cantering and jumping. These mechanical effects of pressure boots may contribute to greater tensile loading of palmar tendons and ligaments, and likelihood of musculoskeletal injury that can be related to animal welfare issues.

Simple Summary Research into the advanced imaging appearance of Thoroughbred racehorse fetlocks is receiving increased attention in an effort to better understand and potentially reduce the occurrence of catastrophic fracture in these horses. Studies in this area commonly use cadaver equine limbs from racehorses and a freeze-thaw process prior to imaging. The low-field magnetic resonance imaging (MRI) appearance of the bones of the fetlock joint is of particular interest in the diagnosis of impending fracture in this location. However, little is known about the effect of the freeze-thaw process on the appearance of certain signal changes (“STIR hyperintensity”) seen commonly in racehorses. This study compares the low-field MRI appearance of short tau inversion recovery (STIR) hyperintensity in the bones of cadaver fetlocks from Thoroughbreds in race training, before and after a freeze-thaw protocol. Fifteen cadaver fetlocks with abnormal bone signal were included in the study. Blinded and unblinded statistical comparisons were made. No overall clinical or statistical difference was detected in intensity and distribution of the STIR signal before and after freeze-thaw. This indicates that the MRI appearance of STIR hyperintensity in freeze-thawed cadaver fetlocks can be considered representative of the appearance of pathology in the recently euthanized horse. This is important information to further advance research in the area of Thoroughbred racing fatality reduction. Abstract Equine advanced imaging research involving racehorse fetlock pathology commonly uses cadaver limbs and a freeze-thaw process. The presence of short tau inversion recovery (STIR) signal intensity in the distal third metacarpal/metatarsal bone is of particular interest and may be clinically relevant in the diagnosis of horses at risk of fracture. However, little is known about the effect of the freeze-thaw process on the MRI appearance of STIR hyperintensity in these bones. This study compares the low-field MRI appearance of the distal third metacarpal/metatarsal bone from cadaver limbs of Thoroughbreds in race training before and after a freeze-thaw protocol. Blinded and unblinded comparisons were made using objective SNR values and subjective grading. Fifteen cadaver limbs with STIR hyperintensity in the distal third metacarpal/metatarsal bone were included. No overall clinical or statistical significance was detected in STIR signal intensity and distribution after freeze-thaw. Three limbs from one horse had individual changes in STIR hyperintensity that were hypothesized to be attributable to ante-mortem haemodynamic abnormalities caused by anaesthesia. These results indicate that the distribution and intensity of STIR hyperintensity in freeze-thawed cadaver fetlocks can be considered representative of the appearance of pathology in the recently euthanized horse. However, care should be taken with horse selection and handling of the cadaver limbs to ensure reliable appearance of STIR signal after freeze-thaw.

Background Capsulitis leads to the release of inflammatory mediators in the joint, causing capsular fibrosis and osteoarthritis (OA). Strain elastosonography (SE) measures the elasticity of tissue by evaluating its strain in operator-dependent deformation. The aims of the study were to assess the feasibility, repeatability, and reproducibility of SE for imaging the distal attachment of the joint capsule (DJC) of metacarpophalangeal joints in sound horses (Group S) and in horses with metacarpophalangeal OA (Group P) and to evaluate differences in the elastosonographic patterns of these horses. After a whole lameness examination, fore fetlock DJCs were assigned to Group S and Group P and were thereafter examined by two operators using SE. Qualitative (i.e., colour grading score) and semi-quantitative (i.e., elasticity index (EI) and strain ratio (SR)) methods were used to evaluate the elastograms. The inter-rater reliability (IRR), intraclass correlation coefficient (intra-CC) and interclass correlation coefficient (inter-CC) were used to compare colour grading scores and the repeatability and reproducibility of EI and SR outcomes. The same parameters were compared between groups. P Results Forty-one horses were included: 11 were in Group S and 30 were in Group P (16 with bilateral OA, 8 with left OA and 6 with right OA). IRR outcomes ranged from good to excellent. For transverse and longitudinal ultrasound scans, the colour grading score of Group S was significantly higher than the metacarpophalangeal DJCs of Group P. Both Inter-CC and intra-CC were higher in Group S than in Group P, with values always > 0.8. Significative differences in EI and SR were detected between groups and between Group S and the affected limb of Group P; values were lower in Group S than in Group P. Conclusions SE can be a useful technique for evaluating DJCs, with good repeatability and reproducibility. DJCs appear softer in sound horses.

International audience; Osteoarthritis (OA) is a significant cause of pain in both humans and horses with a high socio-economic impact. The horse is recognized as a pertinent model for human OA. In both species, regenerative therapy with allogeneic mesenchymal stem cells (MSCs) appears to be a promising treatment but, to date, no in vivo studies have attempted to compare the effects of different cell sources on the same individuals. The objective of this study is to evaluate the ability of a single blinded intra-articular injection of allogeneic bone-marrow (BM) derived MSCs and umbilical cord blood (UCB) derived MSC to limit the development of OA-associated pathological changes compared to placebo in a post-traumatic OA model applied to all four fetlock joints of eight horses. The effect of the tissue source (BM vs. UCB) is also assessed on the same individuals. Observations were carried out using clinical, radiographic, ultrasonographic, and magnetic resonance imaging methods as well as biochemical analysis of synovial fluid and postmortem microscopic and macroscopic evaluations of the joints until Week 12. A significant reduction in the progression of OA-associated changes measured with imaging techniques, especially radiography, was observed after injection of bone-marrow derived mesenchymal stem cells (BM-MSCs) compared to contralateral placebo injections. These results indicate that allogeneic BM-MSCs are a promising treatment for OA in horses and reinforce the importance of continuing research to validate these results and find innovative strategies that will optimize the therapeutic potential of these cells. However, they should be considered with caution given the low number of units per group.

Conventional imaging of the equine fetlock using radiography and ultrasonography can be frustrating in identifying the cause of lameness and in preventing further damage including catastrophic fractures in racehorses. Nuclear scintigraphy had contributed significantly in the diagnosis of fetlock lameness in racing Thoroughbred and Standardbred horses 1, 2 but, in common with many imaging modalities and depending on the system used, nuclear scintigraphy has limitations in terms of sensitivity, specificity and spatial resolution.

OBJECTIVE To describe reliable minimally invasive procedures for (1) removing cartilage by joint distraction and articular drilling for equine metacarpophalangeal (MCP)/metatarsophalangeal (MTP) arthrodesis; (2) applying a palmar/plantar tension band without MCP/MTP joint luxation. STUDY DESIGN Experimental study. SAMPLE POPULATION Cadaveric equine limbs (n = 12). METHODS All limbs were used to evaluate the drilling technique. First the MCP/MTP joint was distracted with a 5.5-mm cortical screw. Then, through four stab incisions, articular cartilage was removed with a 4.5-mm drill. Six randomly chosen limbs were then tested for minimally invasive tension band application with a specially designed cannula. Accurate positioning of the tension band was assessed radiographically. All MCP/MTP joints were disarticulated, and the areas of removed cartilage were visually assessed and measured by using planimetry. RESULTS The mean percentage of removed cartilage was 66.8% ± 7.6% for the metacarpus/metatarsus surface, 67.9% ± 8.6% for the proximal phalanx surface, and 59.5% ± 1% for the two sesamoid bones. The tension band could be accurately placed through four stab incisions with the cannula. CONCLUSION This minimally invasive technique for cartilage removal was efficient and should be favorable for joint fusion in some clinical situations. The minimally invasive tension band application through stab incisions was feasible and repeatable. CLINICAL SIGNIFICANCE These procedures should allow total minimally invasive MCP/MTP arthrodesis and be used in selected clinical cases.

Mineralization of the anatomical structures involved in the limb movement of horses has been reported to inducelameness and interfere with athletic performance. A 4-year-old jumping horse in sport activity was reported at VeterinaryHospital of University of São Paulo, with mild lameness and a mineralized oblique distal sesamoidean ligament (ODSL)of the left forelimb, revealed by a purchase radiographic and ultrasound examination. Mineralization is more commonin tendons than ligaments. This report calls for attention to these structures when performing image exams, even in mildlameness. Long-term favorable follow-up by ultrasonographic and radiographic examination showed that the severeligament injury in this case did not decrease the athletic activity until the present day. A mineralização de estruturas anatômicas envolvidas na movimentação dos membros predispõe à claudicação e interfereno desempenho atlético. Foi admitido no Hospital Veterinário da Faculdade de Medicina Veterinária e Zootecnia daUSP-SP um equino macho, da raça Brasileiro de Hipismo, com quatro anos de idade e histórico de claudicação leve eligamento sesamoideo oblíquo distal mineralizado do membro torácico esquerdo, diagnosticado por exame de compra.A mineralização apresenta alta incidência em tendões, sendo em menor proporção nos ligamentos. Esse relato visaatentar à essas estruturas ao se realizar exames rotineiros de imagem, apesar de claudicação leve. O acompanhamentoa longo prazo por ultrassonografia e radiografia mostrou que lesões graves de ligamentos, como no presente caso, nãodiminuíram a atividade atlética até o momento.

Background : Flexural deformities are anatomical deviations, in varying degrees, of one or more joints, and may have a congenital or acquired origin. Congenital contracture of the deep digital flexor tendon (DDFT) affects newborn calves and results in hyperflexion of the metacarpal-phalangeal joint, which in severe cases means that the animal must support its own weight on its fetlock joints. The aim of this study is to report the rapid and successful result of applying bilateral total tenotomy technique on a newborn bovine that had been diagnosed with severe bilateral DDFT contracture in the thoracic limbs. Case : A 3-week-old male bovine with a history of difficulty in maintaining a quadrupedal position was attended at the Veterinary Hospital of the Federal University of Tocantins. The animal had severe bilateral locomotor alterations in the thoracic members to the point that he walked on his fetlock joints. The physical examination revealed clinical parameters within the normal range. However, the locomotor system examination showed severe flexor deformity in the bilateral metacarpal-phalangeal joints, and the limbs were being supported on the dorsal face of the fetlock joints, which presented ulcerations, and was suggestive of a shortening of the DDFT. Based on the patient's history and clinical examination, as well as the severity of the tendon contractures, surgical treatment using the DDFT bilateral total tenotomy technique was decided upon. Postoperative treatment consisted of 2.5 mg/kg of enrofloxacin intramuscularly (IM), SID, for 5 days and 0.5 mg/kg meloxicam via IM, SID, for 3 days; as well as a dressing (cotton, medical bandage and a PVC mold) on the thoracic limbs to provide support and allow the animal to walk, until its complete recovery. One day after the surgery, the animal was able to walk with difficulty and some trembling; however, on the third day after the surgical procedure, it could stand up by itself, walk and graze normally. The surgical stitches were removed seven days after the operation, as the surgical wounds had healed adequately. The animal was followed-up for a one-month period after the total tenotomy, with no recurrence of any of the clinical signs, and the thoracic limbs had regained normal biomechanics. Discussion : Congenital flexural deformities are common in newborn calves of different breeds and their incidence is mainly in the thoracic limbs, especially in the carpal, distal interphalangeal and metacarpal-phalangeal joints as was reported in the animal in this study. The history and anamnesis of the animal, along with a thorough physical examination, in order to rule out any other congenital alterations, was extremely important in the diagnosis, and the classification of the severity of the deformity along with the choice of appropriate treatment in the present study. Although total tenotomy is rarely reported in the literature, and there are controversial results with calves, the surgical treatment was chosen in the present case due to the severity of the case. The DDFT bilateral total tenotomy surgical technique gave satisfactory results for the correction of severe bilateral flexor deformity in the thoracic limbs of the newborn crossbred calf. Complete recovery of the limb biomechanics was rapid, and there was no post-surgical complications, thus ensuring the animal could have a good and healthy life. Total DDFT tenotomy is considered a viable surgical procedure for calves with severe congenital flexor deformities; however, post-operative care is also important to ensure good final results.

Background : The metacarpal/metatarsophalangeal joints, as well as the suspensory apparatus, are usually affected by injuries, due to the intense physical demand during sports and great range of motion, predisposing to degenerative processes, trauma and rupture of the suspensory apparatus. In this case, arthrodesis is the main technique indicated. Such surgical techniques have a poor prognosis due to post-surgical complications, such as implant infection. Therefore, the study of procedures that promote better joint stabilization is important, with reduced surgical time and tissue exposure, decreasing significantly the chance of infection and other possible complications. Case : A 5-year-old male horse was referred to the hospital with a history of trauma and a lacerating wound in the metatarsal plantar region of the left hindlimb. The animal presented grade IV (I-V) claudication of the left hindlimb with hyperextension of the metatarsophalangeal joint and significant pain on palpation, evidencing the rupture of the superficial, deep digital flexor tendons and suspensory ligament of the fetlock. The initial surgical treatment was performed using the arthrodesis technique described by [16]. The intramedullary nail was used with fixation of the plate on the plantar face of the first phalanx together with a single plate fused to the pin, adjusted according to size of the first phalanx, 13 mm thick x 15 cm long, forming an angle between 120o and 140o. 24 hours after surgery, there was a simple spiral diaphyseal fracture (type A), in the middle third of the third metatarsal bone in the region of the proximal end, due to the lever held by the short nail against the diaphysis cortex. To treat the complication, an intramedullary 316 L surgical steel rod 13 mm thick x 21 cm long was used, filling the entire spinal canal. The nail had three holes at the proximal end and two holes at the distal end allowing the fixation of screws for cortical bone of 5.5 mm at the ends of the third metatarsal bone, stabilizing the fracture. Radiographic control of the limb was performed each 15 days, with immobilization for 90 days after surgery, thus verifying total consolidation. Concomitantly with the immobilization time, the patient showed improvement in the condition and adequate joint stabilization, presenting degree II (I-V) of lameness, due to the process of ankyloses elapsed from joint degeneration. After 10 months, the horse showed a reduction in claudication, classified as grade I (I-V). The owner was satisfied with the functional and aesthetic result of the treatment, where the animal started to be mounted and used for walks. Discussion : In this case, the treatment indicated was an arthrodesis of the metatarsophalangeal joint, due to the hyperextension of the metatarsophalangeal joint and rupture of the suspensory apparatus, since they play a fundamental supporting role. There are many arthrodesis techniques for the metacarpal/metatarsophalangeal joints; however, most of them present several complications, such as implant failure, infections and laminitis of the contralateral limb. For this reason, the development of new techniques that show satisfactory results and less disadvantages in the post-surgical period are fundamental. The nails are advantageous in relation to other fixation methods, presenting lower cost, practical application and allow the support of the fractured limb after return from anesthesia. In the case of simple spiral shaft fractures (type A), the blocked nail system promotes satisfactory stability in the fracture focus, especially for open fractures. When compared to the dynamic compression plate, it is less invasive and can be implanted as a semi-closed surgical procedure, beyond to supporting high loads in vivo .

Background Young Standardbred horses frequently develop fragments in joints. Some fragments represent osteochondrosis; others are considered developmental, but it is uncertain whether they result from preceding osteochondrosis. Osteochondrosis occurs as a consequence of failure of the cartilage canal blood supply and ischaemic chondronecrosis. In heritably predisposed foals, failure was associated with incorporation of vessels into bone. However, bacterial vascular failure was also recently documented in foals suffering spontaneous infections, proving that bacteria can cause osteochondral lesions in foals up to 150 days old. The aim was to determine prevalence of fetlock and hock lesions at screening age in Standardbred horses that survived infections before 6 months of age, and compare this to prevalence reported in the literature. Methods The material consisted of 28 Standardbred horses; 17 males and 11 females that presented and were diagnosed clinically with bacterial infections from 1 to 150 days of age (average: 41.3 days). A screening set of 8 radiographic projections was available from all 28 horses at 7–85 months of age (average: 23.6 months). Lesion prevalence was compared to three previously reported Standardbred cohorts. Results Osteochondral lesions were detected in one or more joints of 19/28 horses (67.9%); in the fetlock joint of 14/28 horses (50%) and the hock joint of 11/28 horses (39.3%). These prevalences were ≥ 2 x higher than the corresponding prevalences in the comparison cohorts, and statistically significantly so in 5:6 comparisons (p-values from

The amount of protraction-retraction of the limbs during water treadmill (WT) walking has implications for postural and muscular development of horses undertaking this exercise for training and rehabilitation purposes. The objective of this study was to compare protraction-retraction of both forelimbs (FLs) and hind limbs (HLs) during dry treadmill (DT) and WT exercise at the typical walking speed of each as used in practice. Inertial motion sensors attached to the metacarpal/metatarsal bones were used to compare maximal protraction (PROMAX), retraction (RETMAX), and total protraction-retraction range of movement (ROM) across five walking conditions: DT at 1.6 m/s; and WT at 0.8 m/s at four water depths, hoof depth (WTHOOF), fetlock depth (WTFET), hock depth (WTHOCK), and stifle depth (WTSTIFLE). Forelimb ROM was lowest at WTSTIFLE and significantly lower than DT (P

Distal sesamoidean ligament (DSL) injury is a recognized cause of lameness in horses. The purpose of this study was to describe the contrast-enhanced computer tomography (CE-CT) findings in horses with injury to the DSL compared to a control group without injury to the DSL. Medical records of horses referred for CE-CT between 2008 and 2015 were reviewed. Cases were selected retrospectively based on a CE-CT imaging finding of injury to the DSL. Three horses had DSL injury as the only finding, while the remaining horses had one or more concomitant injuries. DSL injury and fetlock trauma and/or suspensory branch desmitis were the most frequent injury combinations. CE-CT can be of value in diagnosing DSL injury. The high number of concurrent DSL and fetlock and/or suspensory lesions suggests that further investigation should be considered when evaluating horses with injuries related to either of these structures.

Background Early and accurate detection of stress remodelling in racehorses is of utmost importance to prevent catastrophic injuries. Current imaging techniques have limitations in assessing early changes predisposing to catastrophic breakdowns. Positron emission tomography (PET) using 18 F-sodium fluoride (18 F-NaF) is a sensitive method for the detection of early bone turnover and may improve early recognition of subtle injuries. Objectives To validate the clinical use of 18 F-NaF PET in Thoroughbred racehorses, to assess the value of PET in the detection of bone lesions and to compare PET results with findings of other advanced imaging modalities, clinical examination and pathology. Study design Experimental exploratory study. Methods Twenty fetlocks from nine Thoroughbred racehorses were imaged using 18 F-NaF PET, computed tomography (CT) and scintigraphy. Five fetlocks were also imaged with magnetic resonance imaging and four fetlocks were also examined histologically. Imaging findings were independently reviewed by three board certified radiologists. Imaging, clinical and histopathological findings were correlated. Results PET imaging was well-tolerated by all horses. PET detected focal areas of 18 F-NaF uptake in instances where other imaging modalities did not identify abnormalities, in particular in the proximal sesamoid bones. Maximal standardised uptake values could be measured to quantify the activity of lesions. Areas of 18 F-NaF uptake corresponded to regions of increased vascularity and increased osteoblastic activity. Main limitations Limited number of cases. Conclusions 18 F-NaF PET imaging of the Thoroughbred fetlock is feasible and compares favourably with other imaging modalities in detecting stress remodelling in Thoroughbred racehorses. PET appears to be a beneficial imaging modality when used for early detection of stress remodelling in an effort to prevent catastrophic musculoskeletal injuries in this population of horses.

Polyacrylamide hydrogel (PAHG) is being developed to treat osteoarthritis in horses. Prior to application in osteoarthritic joints, evaluation of PAHG in normal joints is indicated. The objectives of this study are to evaluate the clinical, cytologic, histologic, and metabolic effects of PAHG in normal fetlock joints. This study is an in vivo controlled study utilizing six horses that had each of the four fetlocks assigned to either a 7, 28, 56 days or control group subjected to arthrocentesis only. Synovial fluid was collected prior to administration of 2.5 mL of 4% PAHG and again at the completion of the study for macroscopic, cytological, and cartilage metabolism evaluation. The completion of the study included gross and histologic examination of the cartilage and synovial membrane. There was a small but significant ( P = .0242) increase in cell count in the synovial fluid at 7 days. There were significant changes in the synovial membrane histology score ( P = .0277) as a result of hypertrophic synoviocytes. Biomarkers indicated a small increase in cartilage turnover 7 days after PAHG administration. The PAHG was visible on the surface of the synovium at 7 days, and PAHG appeared in the interstitial spaces of the synovium and intracellular at days 28 and 56. Data from this study provide information as to the tolerance and disposition on an intraarticular injection of PAHG in a normal fetlock joint during a 56-day study. There were no major or permanent detrimental effects seen with the administration of PAHG in normal joints.