Substantial variability exists in the interpretation of survey radiographs among equine veterinarians.

BACKGROUND: Radiographs 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 DESIGN: Worldwide electronic survey of veterinary professionals. METHODS: 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. RESULTS: 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]). MAIN LIMITATIONS: Only one example of each pathological grade per anatomical region was presented. CONCLUSIONS: On survey radiographs, the perceived clinical relevance of radiographic abnormalities among equine practitioners differs widely, making purchase recommendations highly variable.

A safety evaluation of allogeneic freeze-dried platelet-rich plasma or conditioned serum compared to autologous frozen products equivalents in equine healthy joints.

BACKGROUND: Hemoderivatives such as autologous conditioned serum (ACS) and platelet-rich plasma (PRP) have been used as potential disease-modifying therapies in musculoskeletal disorders such as osteoarthritis (OA). These therapies are based on the delivery of multiple growth factors and anti-inflammatory cytokines that are known to participate in inflammatory processes. The variability of cytokine content due to the autologous nature of the product, the non-availability for immediate use and need for storage at low temperatures are limitations for its use in the field. An allogeneic freeze-dried conditioned serum (CS) and PRP would provide field clinicians with a more practical approach to use such products in daily practice. Based on in vitro preliminary data, this experimental study aimed to test the in vivo safety of allogeneic freeze-dried CS and PRP in healthy joints, using the horse as a model. RESULTS: Eight horses were randomly assigned and treated with PRP or CS. Horses had three joints injected with ALLO-FD PRP or CS, and three contralateral joints injected with the AUTO version of the same product, by a blinded clinician. Horses were evaluated clinically, and had synovial fluid collected at different time points and evaluated for cell content, PGE2 and protein. Both CS and PRP products triggered a self-limiting and mild inflammatory response in equine healthy joints. This was indicated by the transient increase in nucleated cell count, PGE2 and total protein in synovial fluid. This mild inflammatory response did not result in significant lameness and was not different among the groups. CONCLUSIONS: The allogeneic freeze-dried PRP and CS showed to be overall safe and not dissimilar compared to their autologous frozen version in equine healthy joints. Further studies are necessary to evaluate the modulatory effects of these therapies in a clinical setting.

Pharmacokinetics, Safety, and Synovial Fluid Concentrations of Single- and Multiple-Dose Oral Administration of 1 and 3 mg/kg Cannabidiol in Horses.

Cannabidiol (CBD) products are widely marketed to horse owners, trainers, and veterinarians and are readily available to the consumer despite minimal pharmacokinetic or safety data being available. The objectives of this study were to determine the plasma pharmacokinetics, short-term safety, and synovial fluid levels of CBD following oral administration in horses. A prospective, randomized, controlled study design was used. Twelve horses were administered sunflower lecithin oil-based CBD at either 1 mg/kg (Group 1) or 3 mg/kg (Group 2) for a 24-hour pharmacokinetic study. Horses then received 0.5 mg/kg (Group 1) or 1.5 mg/kg (Group 2) CBD q12 PO for 6 weeks, with steady state and elimination sampling performed up to 96 hours post-final dose. Synovial fluid CBD concentrations were evaluated at 12 and 24 hours, and 5 weeks. Horses were monitored daily and clinicopathologic parameters were evaluated. Mean ± SD Cmax and tmax were 4.3 ± 2.1 ng/ml and 4.1 ± 4.1 hours, and 19.9 ± 15.6 ng/ml and 5.0 ± 3.7 hours for Groups 1 and 2, respectively. CBD was detectable in synovial fluid in 8/12 horses during steady state. Mild hypocalcemia was seen in all horses and elevated liver enzymes were observed in 8/12 horses, but these changes improved or normalized within 10 days after the final CBD dose. CBD had dose-dependent, but variable, oral bioavailability at 1 mg/kg and 3 mg/kg daily dosing and was consistently detectable at steady state in synovial fluid at the higher dose. Further investigation is needed to establish clinically effective doses.

Deep digital flexor tendon lesions in the pastern are associated with the presence of distal tendinopathy.

BACKGROUND: Correct diagnosis and characterisation of deep digital flexor tendon (DDFT) lesions in equine athletes allows targeted treatment and improved prognostication. OBJECTIVES: To assess the prevalence and character of pathological change within the DDFT in the pastern with concurrent tendon injury distally. It is hypothesised that tendon lesions in the pastern will be associated with tendinopathy within the hoof capsule. STUDY DESIGN: Retrospective descriptive case series. METHODS: Cases with DDFT lesions in the pastern and magnetic resonance imaging (MRI) or ultrasonography of the foot were evaluated retrospectively. Lesion location and type were recorded. Odds ratios were calculated to determine the associations between more distal tendinopathy and the presence of different DDFT lesion types in the pastern. RESULTS: Thirty-four MRI scans of 33 horses and 64 ultrasonographic exams of 58 horses were analysed. Lesion location and type were recorded. Distal DDFT lesions were found in 75% (95% CI: 66.0-84.0) of total cases of pastern DDF tendinopathy and in 97% (95% CI: 91.6-100.0) of cases with core lesions of the DDFT in the pastern. A core lesion in the pastern was significantly more likely (OR = 20.7, 95% CI: 2.2-191.0; P = .008) to be associated with injury in the foot than other types of pastern lesion. MAIN LIMITATIONS: MRIs of the foot were not obtained on all included limbs which did not allow for fully inclusive evaluation of DDFT lesions distal to the navicular bone. CONCLUSIONS: DDFT pathological change in the pastern, particularly core lesions, is associated with additional tendinopathy within the hoof capsule. When a DDFT lesion is found in the pastern, further imaging of the tendon within the foot is indicated to direct appropriate treatment and improve prognostication.

Intermediate patellar ligament desmopathy often occurs in conjunction with other stifle abnormalities.

Intermediate patellar ligament (IPL) desmopathy is a relatively uncommon injury previously reported to have a poor prognosis for return to athletic activity. There is little documentation of the clinical and ultrasonographic features, clinical significance, and outcome for return to work following IPL injury in horses. The aim of this retrospective descriptive study was to describe the clinical and ultrasonographic features of IPL desmopathy, its association with other injuries of the stifle, and outcome for return to work following injury. Forty-two stifles with an ultrasound diagnosis of IPL desmopathy over a 5-year time period were included. Data regarding signalment, clinical presentation, diagnostic imaging findings, treatment, and outcome are described. Intermediate patellar ligament desmopathy occurred most commonly in the midbody (35/42; 83%) of the ligament and lesions were predominantly hypoechoic discrete tears (31/42; 74%) that were obliquely oriented in a craniolateral to caudomedial direction (28/42; 67%). Rarely (1/42; 2%) was IPL desmopathy the only ultrasonographic abnormality detected. Of 13 horses that underwent recheck ultrasound examination, the majority (11/42; 85%) either did not improve or worsened ultrasonographically. Despite this, of 25 horses with long-term follow-up, 23 (92%) returned to work, 16 at the same level or higher. A variety of treatments were utilized. The clinical significance of IPL desmopathy is difficult to determine because it is usually found in conjunction with other stifle abnormalities. Although IPL desmopathy rarely shows ultrasonographic improvement over time, prognosis can be good for return to work.

Usefulness of caudomedial-craniolateral oblique radiographic views for the diagnosis of injury to the origin of the cranial cruciate ligament in two horses.

CASE DESCRIPTION A 12-year-old mixed-breed mare (horse 1) and 6-year-old Friesian gelding (horse 2) were examined for chronic lameness associated with the stifle joint. CLINICAL FINDINGS Lameness examination revealed effusion of the right (horse 1) or left (horse 2) femoropatellar and medial femorotibial joints and grade 3/5 (horse 1) or 4/5 (horse 2) lameness. A diagnosis of cranial cruciate ligament (CCL) injury with associated mineralization and avulsion (horse 1) or mineralization alone (horse 2) was facilitated in both horses with a caudomedial-craniolateral oblique radiographic view obtained 45° medial to the caudocranial line, which highlighted the origin of the ligament on the caudoaxial aspect of the lateral femoral condyle within the intercondylar fossa. These lesions were subsequently confirmed via CT. TREATMENT AND OUTCOME Arthroscopy of the medial and lateral femorotibial joints was performed for horse 1 and revealed the osseous fragment associated with the CCL, but the fragment could not be removed. Horse 2 was euthanized while anesthetized following CT owing to the poor prognosis. CONCLUSIONS AND CLINICAL RELEVANCE Radiography is typically the first imaging modality attempted for horses with CCL injury, particularly outside the hospital setting. A 45° caudomedial-craniolateral oblique radiographic view may aid in diagnosis of CCL injury when avulsion or mineralization is present. Although this view is not commonly included in the typical radiographic series for imaging of the stifle joint in horses, it should be considered when CCL injury is suspected.

Management and Rehabilitation of Joint Disease in Sport Horses.

Joint disease is one of the most common issues effecting sport horses. Because there is no cure for joint disease, treatment goals surround slowing progression of the disease, minimizing pain, increasing function, and optimizing performance. Accomplishing these goals often requires a multimodal approach that combines systemic medications or supplements; intra-articular therapies, such as corticosteroids or biologics; management considerations; and physical therapy exercises.

Relationship between repository radiographic findings and subsequent performance of Quarter Horses competing in cutting events.

OBJECTIVE To investigate potential associations between repository radiographic findings and subsequent performance of Quarter Horses competing in cutting events. DESIGN Retrospective cohort study. SAMPLE Repository radiographs (ie, radiographs obtained at the time of sale) for 343 client-owned horses. PROCEDURES Repository radiographic findings were compared with objective measures of performance, including the likelihood of competing; the likelihood of earning money as a 3-year-old, as a 4-year-old, and as a 3- and 4-year-old combined; and the amount of money earned as a 3-year-old, as a 4-year-old, and as a 3- and 4-year-old combined. RESULTS The presence of mild osteophytes involving the distal aspect of the tarsal joint was significantly associated with lower mean earnings as a 4-year-old. The presence of osteophytes on the dorsoproximal aspect of the middle phalanx of the hind limbs was significantly associated with an increased odds of earning money as a 4-year-old. Radiographic lesions of the medial femoral condyle of the stifle joint were not significantly associated with subsequent performance. CONCLUSIONS AND CLINICAL RELEVANCE Most abnormalities identified on repository radiographs were not significantly associated with subsequent performance. The significant association between mild tarsal osteophytosis and earnings was unexpected. Results of the present study indicated the need for further investigation of the relationship between radiographic findings and performance outcome in Western performance horses.

Effect of limb positioning on the radiographic appearance of the distal and proximal interphalangeal joint spaces of the forelimbs of horses during evaluation of dorsopalmar radiographs.

OBJECTIVE: To determine the effect of limb positioning on the radiographic appearance of the distal and proximal interphalangeal joint spaces of the forelimbs of horses during evaluation of dorsopalmar radiographs. DESIGN: Evaluation study. ANIMALS: 14 forelimbs from 9 adult horses. PROCEDURES: Each horse was in standing position with its forelimbs positioned on blocks. Dorsopalmar radiographs of each foot were obtained with the forelimbs positioned squarely (the metacarpus of both forelimbs was perpendicular to the ground as determined by visual examination [abducted 0°]; baseline) and abducted 5° and 10°. The width of the space at the medial and lateral aspects of the distal and proximal interphalangeal joints (medial and lateral joint space width, respectively) was measured. Mediolateral joint balance was calculated as the difference between the widths of the lateral and medial joint spaces, and joint space width and mediolateral joint balance were compared among all 3 positions. RESULTS: As the extent of limb abduction increased, the medial aspect of the proximal and distal interphalangeal joints became narrower, compared with the corresponding lateral aspect of those joints. For both the distal and proximal interphalangeal joints, the mediolateral joint balance differed significantly among all limb positions. CONCLUSIONS AND CLINICAL RELEVANCE: Forelimb position significantly affected the mediolateral joint balance of the interphalangeal joints of horses. Thus, it is crucial that the forelimbs of horses be squarely positioned when dorsopalmar radiographs are obtained for accurate evaluation of interphalangeal joint space and balance.

Evaluation of sedation and analgesia in standing horses after administration of xylazine, butorphanol, and subanesthetic doses of ketamine.

OBJECTIVE: To evaluate the sedative and analgesic effects of subanesthetic doses of ketamine in horses sedated with xylazine, with or without butorphanol. DESIGN: Prospective, randomized, controlled study. ANIMALS: 10 adult horses. PROCEDURES: Each horse was sedated multiple times by administration of xylazine (treatment X), xylazine and butorphanol (treatment XB), xylazine with 1 of 2 dosages of ketamine (treatment XK1 or XK2), or xylazine and butorphanol with 1 of 2 dosages of ketamine (treatment XBK1 or XBK2). Head height and various behaviors, including responses to noise, insertion of a dental float, needle prick on the flank, algometer pressure on the scapula, and bilateral carpal arthrocenteses, were evaluated. RESULTS: No significant differences were detected among sedation treatments for head height, response to noise, or response to arthrocenteses. Insertion of a dental float was easiest with treatment XBK2 and most difficult with treatments XK1 and XK2. Response to a needle prick on the flank was lowest with treatment XB and highest with treatment XK2. Tolerance to algometer pressure over the scapula was highest with treatment XBK2 and lowest with treatment X. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of a subanesthetic dosage of ketamine with xylazine and butorphanol may facilitate certain procedures, such as insertion of a dental float, in horses and enhance tolerance to pressure stimulation, but it may worsen responses to acute pain, such as that caused by a needle prick. Further evaluation is needed to determine whether subanesthetic dosages of ketamine might be useful when performing certain clinical procedures in horses.