Resources: Scientific papers


Click on a week to access resources including scientific papers from AAEP Convention Proceedings.
 


Session 1: These papers were referenced during the live virtual session on Tuesday, August 4.

In Vivo investigation of communication between the distal intertarsal and tarsometatarsal joints in horses and ponies
Brendon Bell, et al

This study concurs with the results of previous investigators that the frequency of communication between the tarsometatarsal and distal intertarsal joints of the equine tarsus is approximately 25%. In the diagnosis and intra-articular treatment of spavin, the TMT and DIT joints should be injected separately.

In vitro biomechanical evaluation of four surgical techniques for fusion of equine centrodistal and tarsometatarsal joints
Adam Biedrzycki, et al

The objective of this study was to evaluate the biomechanical properties of 4 methods for fusion of the centrodistal and tarsometatarsal joints in horses and compare them among each other and with control tarsi.

Fusion of the distal intertarsal and tarsometatarsal joints in the horse using intra-articular sodium monoiodoacetate
Tom C. Bohanan, et al.

Osteoarthritis of the distal tarsal joints, or bone spavin, is the most frequent cause of lameness associated with the tarsus. This study followed six normal horses that received 3 intra-articular injections of sodium monoiodoacetate in the distal intertarsal and tarsometatarsal joints of one hindlimb.

Alcohol-facilitated ankylosis of the distal intertarsal and tarsometatarsal joints in horses with osteoarthritis
James L. Carmalt, et al.

The purpose of this study was to assess the safety and efficacy of alcohol-facilitated ankylosis of the distal intertarsal and tarsometatarsal joints in horses with osteoarthritis (bone spavin). It concluded that intra-articular alcohol injection in horses with bone spavin resulted in a rapid (usually within 3 months) reduction in lameness and joint space collapse.

Chemical arthrodesis of the distal tarsal joints using sodium monoiodoacetate in 104 horses
BA Dowling, et al.

This article evaluated chemical arthrodesis using sodium monoiodoacetate for treatment of degenerative joint disease of the tarsometatarsal and distal intertarsal joints and found that chemical arthrodesis using sodium monoiodoacetate was an effective treatment method for degenerative joint disease of the distal tarsal joints.

An investigation into the occurrence of, and risk factors for, concurrent suspensory ligament injuries in horses with hindlimb proximal suspensory desmopathy
Sue J. Dyson, et al.

The aims of this retrospective case-control study from January 2009 to December 2018 were to describe the occurrence of, and identify risk factors for, concurrent suspensory ligament injuries in horses with hindlimb proximal suspensory desmopathy.

Management of hindlimb proximal suspensory desmopathy by neurectomy of the deep branch of the lateral plantar nerve and plantar fasciotomy: 155 horses (2003–2008)
Sue J. Dyson, et al.

The objective of this study was to describe long-term follow-up in horses with proximal suspensory desmitis alone or with other injuries contributing to lameness and poor performance, including complications following neurectomy and fasciotomy.

Surgical arthrodesis for the treatment of bone spavin in 20 horses
GB Edwards

Over a 3-year period, 20 horses with bone spavin were treated by surgical arthrodesis of the affected joints. The horses chosen for surgery were those with osteoarthritis, but with little or no evidence of periostitis.

Excision of the deep branch of the lateral palmar nerve of horses to resolve lameness caused by proximal suspensory desmitis
Paolo Gay Guasco, et al.

The purpose of this study was to assess outcome after neurectomy of the deep branch of the lateral palmar nerve as a treatment for horses with persistent lameness associated with chronic proximal suspensory desmitis of the thoracic limb.

Laser-facilitated arthrodesis of the distal tarsal joints
Brent A. Hague, et al.

Laser-assisted arthrodesis offers a minimally invasive surgical procedure with a relatively short convalescent period that eliminates the clinical signs of lameness in a high number of cases.

Use of ethanol in the treatment of distal tarsal joint osteoarthritis: 24 cases
LP Lamas, et al.

This study describes and evaluates the results of treatment of distal tarsal joint osteoarthritis by facilitated ankylosis stimulated by intra-articular ethanol injection.

The relationship between sagittal hoof conformation and hindlimb lameness in the horse
Lynn Pezzanite, et al.

The aim of this article was to determine if there was an association between hoof balance in the sagittal plane and hind limb lameness. It was determined that horses with hind limb lameness localized to the distal tarsus and proximal metatarsus, but not the stifle, were more likely to have negative/neutral plantar angle of the distal phalanx.

Comparison of intra-articular drilling and diode laser treatment for arthrodesis of the distal tarsal joints in normal horses
C. Scruton, et al.

Intra-articular drilling may provide earlier arthrodesis of the distal tarsal joints, but not necessarily a better long-term result. This study aimed to evaluate intra-articular drilling and laser facilitated arthrodesis using in situ and in vivo techniques.

Compressive damage to the deep branch of the lateral plantar nerve associated with lameness caused by proximal puspensory desmitis
Ferenc Tóth, et al.

Horses lame because of proximal suspensory desmitis of the pelvic limb may remain lame after desmitis has resolved because of compression of the deep branch of the lateral plantar nerve. Excising a portion of this nerve may resolve lameness.

Comparison of three methods for arthrodesis of the distal intertarsal and tarsometatarsal joints in horses
Chad J. Zubrod, et al.

This experimental study evaluated the effects of diode laser surgery, surgical drilling, and intra-articular sodium monoiodoacetate as methods for fusing the distal intertarsal and tarsometatarsal joints in horses.

Session 2: These papers were referenced during the live virtual session on Thursday, August 6.

Nonseptic tenosynovitis of the digital flexor tendon sheath caused by longitudinal tears in the digital flexor tendons: A retrospective study of 135 tenoscopic procedures
L. Arensberg, et al.

This study determined the prevalence of longitudinal tears of the digital flexor tendons in a large population of horses undergoing diagnostic tenoscopy of the digital flexor tendon sheath and assessed the outcome of surgical treatment and the factors influencing the outcome.

Comparison of tenoscopic and ultrasonographic methods of examination of the digital flexor tendon sheath in horses
J. Edinger, et al.

The purpose of this study was to compare sonographic and tenoscopic findings with the purpose of establishing the accuracy and limitations of ultrasonography as a non-invasive diagnostic modality in evaluating the digital flexor tendon sheath and its enclosed tendons.

Tenoscopic surgical treatment of tears of the manica flexoria in 53 horses
Judith Alice Findlay, et al.

The purpose of this case series was to show typical clinical features associated with tears of the manica flexoria and prognosis for return to athletic function after surgical resection.

Indications and techniques for tenoscopic surgery of the digital flexor tendon sheath
Lisa A. Fortier

Tenoscopic surgery should be considered as a first-line treatment modality in cases of septic tenosynovitis. In cases of aseptic tenosynovitis, the decision to perform tenoscopy is based on history, lameness examination and a thorough ultrasonographic examination of the digital sheath.

Outcome of palmar/plantar digital neurectomy in horses with foot pain evaluated with magnetic resonance imaging: 50 cases (2005–2011)
S.D. Gutierrez-Nibeyro, et al.

This is a multicenter restrospective study reporting the short- and long-term outcomes of horses that underwent palmar/plantar digital neurectomy (PDN) to alleviate chronic foot pain due to lesions diagnosed by magnetic resonance imaging and factors that may influence the outcome of PDN.

Magnetic resonance imaging of navicular bursa adhesions
Maureen E. Holowinski, et al.

The objectives of this study were to describe the appearance of navicular bursa adhesions on high-field magnetic resonance images, to compare these findings to findings at navicular bursoscopy, and to determine the prevalence of lesions in the remainder of the podotrochlear apparatus.

Core decompression of the equine navicular bone: An in vivo study in healthy horses
Florien Jenner, et al.

The purpose of this study was to determine the physiologic response of the equine navicular bone to core decompression surgery in healthy horses.

Guillotine versus pull-through technique for palmar digital neurectomy: A retrospective study on 40 horses
M. Oosterlinck, et al.

This study compares the outcome of the guillotine technique and the pull-through technique for palmar digital neurectomy.

Noninfected tenosynovitis of the digital flexor tendon sheath: A retrospective analysis of 76 cases
M.R.W. Smith, et al.

Tenosynovitis of the digital flexor tendon sheath may result from tears in the deep or superficial digital flexor tendons, manica flexoria or other structures with synovial communication. To date, these can be identified confidently only by tenoscopy, which also permits appropriate lesion management.

Endoscopic evaluation of the navicular bursa: Observations, treatment and outcome in 92 cases with identified pathology
M.R.W. Smith, et al.

Lameness localizing to the navicular bursa is commonly associated with injuries to the dorsal border of the deep digital flexor tendon. Endoscopy permits identification and characterization of injuries within the navicular bursa and enables lesion management. Outcome following debridement is related to severity of injury but overall is reasonable.

Additional Resources

Injuries of the accessory ligament of the deep digital flexor tendon in forelimbs and hindlimbs
Sue Dyson, MA, Vet MB, PhD, DECVSMR, FRCVS

Typical injuries of the accessory ligament of the deep digital flexor tendon (ALDDFT) are associated with sudden onset lameness and swelling in the metacarpal or metatarsal region and are straightforward to diagnose. Diagnosis is reliant on diagnostic analgesia and ultrasonography, or occasionally magnetic resonance imaging. In hindlimbs, degenerative lesions of the ALDDFT may result in a postural change with inability to load the heel or flexion of the fetlock.

Retrospective analysis of lameness localization in Western performance horses
Sherry A. Johnson, DVM, et al

The distal forelimb and proximal metatarsus were the two most common anatomic regions of lameness based on response to diagnostic analgesia. Determining the source of lameness through diagnostic analgesia remains challenging, but the continued assessment of response to diagnostic analgesia may help characterize discipline-specific injuries.

Long-term outcome after stifle arthroscopy in Western performance horses: 82 cases
Annette M. McCoy, DVM, MS, PhD, DACVS, et al

The prognosis for Western performance horses undergoing stifle arthroscopy is similar to the prognosis reported for horses undergoing stifle arthroscopy for other breeds of horses. Increased age and degree and duration of lameness and presence of partial-thickness cartilage lesions affected the odds of a horse returning to work.

Osteochondral fragments of the pastern joint: Performance assessment after arthroscopic removal
Christine T. Moyer, DVM, MS, et al

Osteochondral fragments in the dorsal proximal interphalangeal joint occur within the origin of the collateral ligament of the distal sesamoid bone and can be removed arthroscopically in young horses with a favorable prognosis for athletic performance. When fragments are removed arthroscopically from young horses, athletic performance is similar to matched controls.

Effect of pre-race inflammatory biomarkers on race performance in Thoroughbreds
Allen E. Page, DVM, PhD, et al

Pre-race inflammation is lower in graded stakes horses compared to claiming and allowance horses. Some claiming horses had significantly elevated pre-race inflammatory markers when compared to other horses.

Preliminary study of risk factors associated with biaxial proximal sesamoid bone fractures in Thoroughbred Racehorses
Scott E. Palmer, VMD, DABVP, et al

A preliminary screening profile was developed to help identify horses at risk for biaxial proximal sesamoid bone fracture. This study provides a useful preliminary screening profile to help identify Thoroughbred racehorses at risk for biaxial proximal sesamoid bone fracture.

Subchondral bone pain: The fetlock joint in racehorses and Sports Horses 
Michael W. Ross, DVM, DACVS

The metacarpophalangeal and metatarsophalangeal joints in the fetlock joints of racehorses are the most important source of pain causing lameness and poor performance, but clinical recognition can be perplexing and frustrating. Intra-articular analgesia of the fetlock joint can abolish pain from branch desmitis (and from oblique sesamoidean desmitis) and low-palmar/plantar (low 4-point) analgesia can abolish pain from chronic suspensory desmitis and osteoarthritis of the fetlock joint.

Surgical management of soft tissue injuries: Update
Michael W. Ross, DVM, DACVS

Suspensory desmitis associated avulsion injury of the proximal aspect of the third metacarpal/metatarsal bones and insertional injury (branch desmitis) on the proximal sesamoid bones are two of the most important soft tissue injuries in the racehorse and non-racehorse sport horse. A relationship with chronic recurrent suspensory desmitis (particularly branch desmitis) and chronic osteoarthritis of the fetlock joint appears to exist.

An investigation of the association between hindlimb conformation and suspensory desmopathy in Sports Horses
Jenny Routh, BSc, BVSc, et al

There is an association between hindlimb proximal suspensory desmopathy and large tarsal angles. Standardization of positioning the horse is crucial for acquiring repeatable measurements.

Session 3: These papers were referenced during the live virtual sessions on Tuesday, August 11 and Thursday, August 13.

A comparison of arthroscopy to ultrasonography for identification of pathology of the equine stifle
AM Adrian, et al.

The purpose of this study was to evaluate and compare arthroscopic and ultrasonographic examinations for characterizing pathological change in the stifle joint; to describe how the results of arthroscopic and ultrasonographic examinations may differ in characterizing the severity of lesions; and to evaluate which lesions are best assessed with each modality.

A review of normal radiographic variants commonly mistaken for pathologic findings
Myra F. Barrett, et al.

Normal anatomic variants can be mistaken for radiographic lesions. Recognition of normal variants helps prevent radiographic misdiagnosis. This paper reviews common sites of error.

How to obtain flexed lateral oblique radiographs of the equine stifle
Myra F. Barrett, et al.

The flexed lateral oblique view is a view that is rarely discussed in the literature and is often underutilized. This paper explains how to obtain this radiographic projection.

Magnetic resonance imaging characterization of lesions within the collateral ligaments of the distal interphalangeal joint: 28 cases
B. Beasley, et al.

This study showed that collateral ligament desmopathy of the distal interphalangeal joint was the most significant finding in 28/427 (6.6%) cases that underwent MRI of the foot following lameness examination that localized a component of the lameness to the foot.

Metacarpophalangeal joint lesions identified on magnetic resonance imaging with lameness that resolves using palmar digital nerve and intra-articular analgesia
E
rin K. Contino, et al.

This study describes lameness cases that subjectively improved >90% with a palmar digital nerve block that were diagnosed with primary metacarpophalangeal (MCP) joint lesions based on MRI and subsequent intra-articular MCP joint analgesia.

An optimized injection technique for the navicular bursa that avoids the deep digital flexor tendon
AJ Daniel, et al.

This objective of this study was to report a radiographic-guided injection from the lateral aspect of the limb that avoids puncture of the deep digital flexor tendon and to assess synovial and soft tissue penetration by the needle.

A technique of needle redirection at a single craniolateral site for injection of three compartments of the equine stifle joint
Meredith RA Herdrich, et al.

The purpose of this study was to determine accuracy for a technique of needle redirection at a single craniolateral site for injection of 3 compartments of the equine stifle joint, to describe the external needle position, and to identify the location of the needle tip within each joint compartment.

A review of normal radiographical variants commonly mistaken for pathological findings in horses
France E. Hinkle, et al.

There are multiple radiographical variants associated with normal conformational or anatomic variations. Recognizing these normal variants is essential to avoid inappropriate radiographical interpretation and subsequent improper case management.

Additional palmaroproximal–palmarodistal oblique radiographic projections improve accuracy of detection and characterization of equine flexor cortical lysis
Sherry A. Johnson, et al.

The aims of this prospective, diagnostic accuracy study were to determine effects of radiographic beam angle and observer on accuracy of lesion detection.

An ultrasound-guided, tendon-sparing, lateral approach to injection of the navicular bursa
K. Nottrott, et al.

The purpose of this study was to describe and evaluate the feasibility and efficacy of an ultrasound-guided, lateral bursocentesis technique.

Intra-articular anesthesia of the equine stifle improves foot lameness
A Radtke, et al.

This study aimed to determine if intra-articular stifle anesthesia could alleviate lameness originating in the distal limb. It found that intra-articular stifle anesthesia reduced foot lameness in a third of horses by up to 50% within 30 min.

How to perform synoviocentesis of the navicular bursa
Michael C. Schramme, et al.

Synoviocentesis of the navicular bursa is performed as part of an examination for lameness because it is the most localizing analgesic procedure that can be performed during an investigation to determine the site of pain within the horse’s foot.

Assessment of the tissue diffusion of anesthetic agent following administration of a low palmar nerve block in horses
Kathryn A. Seabaugh, et al.

The purpose of this study was to investigate tissue diffusion of anesthetic agent following administration of low palmar nerve blocks in horses.

Review: A field guide to better radiographs
Kurt Selberg, et al.

Patient preparation and positioning, adequate technique, and knowing how to correct mal-positioned radiographs are skills in achieving diagnostic radiographic images. Taking a moment to assess unintentional obliquity, patient conformation, and stance and appropriately using distance and collimation can reduce retakes and reduce radiation exposure.

How to perform radiographic-guided needle placement into the collateral ligaments of the distal interphalangeal joint
Natasha M. Werpy, et al.

Radiography-guided needle placement into the distal aspect of the collateral ligaments of the distal interphalangeal joint can be used to facilitate injection of intralesional therapy.

Ultrasound of the equine stifle: Basic and advanced techniques
Mary Beth Whitcomb

Ultrasound of the stifle can be a challenging but rewarding experience, made easier by a strong knowledge of stifle anatomy. This paper serves as a useful guide and resource for future stifle scans.

SOUND Equine Radiographic Positioning Guide

Effects of analgesia of the digital flexor tendon sheath on pain originating in the sole, distal interphalangeal joint or navicular bursa of horses
J. Harper, et al.

The purpose of this study was to determine if analgesia of the digital flexor tendon sheath results in anesthesia of other portions of the foot, such as the sole, distal interphalangeal joint, or navicular bursa.

Evaluation of the diffusion of corticosteroids between the distal interphalangeal joint and navicular bursa in horses
Frederik Pauwels, et al.

The objective of this study was to determine whether clinically effective concentrations of methylprednisolone or triamcinolone can be achieved in the navicular bursa after injection of methylprednisolone acetate (MPA) or triamcinolone acetonide (TA) into the distal interphalangeal joint (DIPJ) and whether clinically effective concentrations of these drugs can be achieved in the DIPJ after injecting the navicular bursa with the same doses of MPA or TA.

A comparison of the effects of two volumes of local analgesic solution in the distal interphalangeal joint of horses with lameness caused by solar toe or solar heel pain
John Schumacher, et al.

This paper examines the response of horses, with solar pain in the dorsal or palmar aspect of the foot, to 6 or 10 ml local analgesic solution administered into the distal interphalangeal joint.

Comparison of four techniques of arthrocentesis of the lateral compartment of the femorotibial joint of the horse
John Schumacher, et al.

Clinical experiences indicate that centesis of the lateral compartment of the femorotibial joint is often unsuccessful. The paper aimed to determine the accuracy of 2 published and 2 unpublished techniques of centesis of the lateral compartment of the femorotibial joint.

Diagnostic analgesia of the equine digit
J. Schumacher, et al.

This paper presented a summary of current knowledge of the use of analgesia to localize sites of pain within the digit of lame horses.

Diagnostic analgesia of the equine forefoot
J. Schumacher et al.

This paper presented a summary of current knowledge of the use of analgesia to localize sites of pain in the forefoot of lame horses.

Effect of anesthesia of the palmar digital nerves on proximal interphalangeal joint pain in the horse
J. Schumacher, et al.

The purpose of this paper was to determine the response of horses with pain in the PIP joint to anesthesia of the palmar digital nerves.

Effects of analgesia of the distal interphalangeal joint or palmar digital nerves on lameness caused by solar pain in horses
John Schumacher, et al.

The aim of this paper was to determine if pain of the dorsal margin of the sole in horses can be attenuated by anesthesia of either the distal interphalangeal joint or the palmar digital nerves.

The effects of local anesthetic solution in the navicular bursa of horses with lameness caused by distal interphalangeal joint pain
John Schumacher, et al.

This paper aims to determine the response of horses with pain in the distal interphalangeal joint to instillation of local anesthetic solution into the navicular bursa.

Additional Resources

Multimodality imaging of the equine distal limb: Beyond the foot
Myra F. Barrett DVM, MS, DACVR

When selecting where to image and the appropriate modality, it is important to account for the patient's response to other nerve blocks as well as take note of any physical exam findings that may help better target the likely source of lameness. The exam for a patient with lameness localized to the distal limb should be performed systematically and extended proximally and distally as needed to identify the lesion.

How does the imaging diagnosis dictate a rehabilitation program?
Erin K. Contino, DVM, MS, DACVSMR

Diagnostic imaging is a critical component in obtaining an accurate diagnosis. While a thorough lameness examination, including diagnostic analgesia, is usually required to localize the lameness, diagnostic imaging enables characterization of the size, severity, location, and tissue involved in the injury or disease process. These specifics often dictate the type of treatment(s) selected, the prognosis, the projected length of rehabilitation, and the physical therapy modalities that may be of greatest benefit.

How to diagnose subchondral bone injury of the fetlock in Sport Horses using field radiography
Laura Faulkner, VMD, et al.

Subchondral bone injuries of the distal third metacarpal and third metatarsal bones and proximal first phalanx have long been recognized as common causes of lameness in Thoroughbred and Standardbred racehorses. Equine ambulatory practitioners are strongly encouraged to obtain both standard and nonstandard radiographic views of the fetlock joint as part of the diagnostic process for fetlock joint-related lameness.

MRI findings of the proximal metacarpus in Cutting Horses
Philippe T. Manchon, BVSc, et al

Cutting horses with proximal suspensory disease have significant pathologic change within the proximal suspensory ligament and its enthesis. Accurate diagnostic imaging allows the lameness clinician to select treatment protocols targeted to each disease process.

Practical use of ultrasound in Thoroughbred racehorse lameness diagnosis
Chris O’Sullivan

Ultrasound imaging is the mainstay diagnostic for investigation of tendon and ligament injuries in racing Thoroughbreds. It has evolved in Thoroughbred racetrack practice to be used commonly in a variety of other areas as a standalone or complementary diagnostic, particularly to investigate tendon sheaths, curb swellings, joints, muscle, pelvic, and back injuries.

Use of MRI to evaluate fetlock region pain on the Sport Horse
W. Rich Redding, DVM, MS, DACVS, DACVSMR

The main advantage of using MRI to evaluate lameness felt to originate in the fetlock region is accurate definition of the specific cause of lameness. As many injuries are not often apparent with conventional imaging tools (radiographic and ultrasonographic examination), it may be that MRI is the only imaging tool capable of demonstrating the injury.

Clinical, diagnostic, and therapeutic considerations for management of suspensory ligament branch injuries in Sport Horses
Mark Revenaugh, DVM, et al

Injuries to the suspensory branches are common in sport horses and vary in clinical presentations. A careful clinical exam coupled with diagnostic imaging can help in diagnosis and characterization of the injury. This paper will review anatomy, pathology, diagnostic nerve block patterns, imaging, and widely used management techniques and therapeutic modalities.

Imaging of the foot
Kurt Selberg, MS, DVM, MS, DACVR

Lameness is a frequent medical problem in horses. Aside from localizing techniques such as palpation and subsequent diagnostic blocking, radiographic and ultrasonographic investigation of the limbs are the first lines of diagnostics used in the field.

Ultrasonographic diagnosis of humeral stress fractures in Racehorses
Betsy Vaughan, DVM, DACVSMR, et al

Ultrasound is a useful, economical screening tool to identify humeral stress fractures and can be used with radiography to monitor healing. Affected horses can return to racing following appropriate rehabilitation.


Articles recommended by Dr. Elizabeth Davidson 

How to perform sonographic examination and ultrasound-guided injection of the cervical vertebral facet joints in horses
Katherine Chope

The purpose of this presentation was to briefly review the normal appearance of the cervical facet joints, describe the author’s injection technique, and review selected clinical cases.

Radiographic retrospective study of the caudal cervical articular process joints in the horse
S.S. Down, et al

This study investigated the associations of cervical articular process joint enlargement at the C5-C6 and C6-C7 articulations with case subject details (breed, age, sex, usage) and clinical signs.

Equine lameness: Clinical judgment meets advanced diagnostic imaging
Sue Dyson

Accurate lameness diagnosis remains challenging and as knowledge advances, more questions arise. Current diagnostic capabilities are superior to the veterinarian’s ability to treat lameness successfully. This manuscript aims to discuss the science and art of lameness diagnosis.

Subjective gait assessment of 57 sports horses in normal work: A comparison of the response to flexion tests, movement in hand, on the lunge, and ridden
Sue Dyson, et al.

The objectives of this study were to compare the response to flexion tests, movement in hand, on the lunge, and ridden in sports horses in regular work, assumed to be sound by the owners.

Unexplained forelimb lameness possibly associated with radiculopathy
S.J. Dyson

The objectives of this retrospective study were to describe the clinical features, response to diagnostic analgesia and imaging findings in horses with forelimb lameness that were not improved by diagnostic analgesia.

Where does it hurt? Problems with interpretation of regional and intra-synovial diagnostic analgesia
R. Pilsworth, et al.

This review discusses the ways in which local analgesic techniques can cause confusion and highlights how important it is to recognize that the majority of methods are less specific than was formerly thought.

Evaluation of the diagnostic accuracy of skeletal scintigraphy in lame and poorly performing sports horses
L.E. Quiney, et al

Scintigraphic examination is unlikely to lead to a full and correct diagnosis of the cause(s) of lameness or poor performance in sports horses when used as an isolated or indiscriminate screening tool.

Articles recommended by Dr. Amy Johnson

Cerebrospinal fluid Lyme multiplex assay results are not diagnostic in horses with neuroborreliosis
Amy L. Johnson, et al.

Positive Lyme multiplex results were common in horses with neurologic diseases and did not adequately differentiate horses with neuroborreliosis from horses with other disorders.

Cervical radiographs: A neurologist’s perspective
Amy L. Johnson, DVM, DACVIM (LAIM & Neurology)

Cervical vertebral problems are a relatively common cause of decreased performance in sport horses. Equine practitioners should be knowledgeable about proper acquisition and interpretation of cervical radiographs so that they can advise clients appropriately.

Equine protozoal myeloencephalitis: One disease, many symptoms
Amy L. Johnson, DVM, DACVIM (LAIM & Neurology)

Equine protozoal myeloencephalitis is the most commonly diagnosed infectious neurologic disease of horses in the United States. However, widespread equine exposure to the causative organisms leads to overdiagnosis and unwarranted treatment. Application of appropriate diagnostic criteria and the most accurate tests will permit accurate diagnosis. Several treatment options are available for affected horses.

Headshaking: Where to start?
Amy L. Johnson, DVM, DACVIM (LAIM & Neurology)

Headshaking is a self-explanatory syndrome but diagnosis of the underlying etiology can be difficult, and clinical management can be even harder. Recent investigation has provided more information regarding the underlying physiologic problem in many cases, and newly described treatment modalities can help improve horse comfort.

Lyme disease and neuroborreliosis: What do we know?
Amy L. Johnson, DVM, DACVIM (LAIM & Neurology)

Infection with Borrelia burgdorferi is common but rarely results in neuroborreliosis. Horses with neuroborreliosis have variable signs and laboratory results. Therefore, diagnosis is challenging and relies on fulfillment of several criteria plus exclusion of other possible diseases.

Neurologic, lame, or both?
Amy L. Johnson, DVM, DACVIM (LAIM & Neurology)

Horses fail to meet performance expectations for many reasons, with lameness being one of the most common. Neurologic disease can mimic or be mistaken for an orthopedic problem, and some horses might have both problems. Careful clinical examination and appropriate diagnostic testing and interpretation are the keys to accurate diagnosis.

Accurate antemortem diagnosis of equine protozoal myeloencephalitis based on detecting intrathecal antibodies against Sarcocystis neurona using the SnSAG2 and SnSAG4/3 ELISAs
S.M. Reed, et al

The study was conducted to assess whether the antigen-specific antibody indices can be reduced to a simple serum : cerebrospinal fluid titer ratio to achieve accurate EPM diagnosis.

Other Suggested Resources

Grade 3 left laryngeal movements in young Thoroughbreds do not impair future racing performance
Brian H. Anderson, BVSc, MVSc, MS, MANZCVSc, DACVS, et al

A 5-point grading system for laryngeal movements is used at Thoroughbred sales in New Zealand. Results in this paper find that future racing performance is not significantly different between horses with laryngeal movements grade 3 and <3.

Investigating the response of EIPH to different potential prophylactic treatments
Warwick Bayly, BVSc, MS, PhD, et al

Treatment with 0.5 mg/kg furosemide IV 24 hours before strenuous exercise, when combined with controlled access to water, shows potential for attenuating the severity of exercise-induced pulmonary hemorrhage in racehorses. The number of horses in this study was small but the findings are promising.

The impact of grade of arytenoid function immediately prior to laryngoplasty and ipsilateral ventriculocordectomy on postoperative performance: 601 Thoroughbred racehorses (1998-2013)
Ali H. Broyles, DVM, DACVS-LA, et al

This study determined the effect of arytenoid function grade prior to laryngoplasty and ventriculocordectomy on postoperative performance. Findings show the grade of arytenoid function affects return to racing but not earnings.

Couetil L. Impact of pulmonary disease on performance: A review
Laurent Couetil, DVM, PhD, DACVIM

Knowledge of how respiratory diseases cause poor performance in horses and the value of various diagnostic tests at detecting these diseases will allow practitioners to implement targeted therapy and management strategies.

Efficacy of furosemide dosed 4 vs 24 hours pre-race
Heather K. Knych, DVM, PhD, DACVCP, et al.

Although none of the treatments prevented exercise-induced pulmonary hemorrhage in the horses included in this study, reduced red blood cell counts in bronchoalveolar fluid post-race indicated that administering furosemide 4 hours before a race was the most effective for reducing the severity of EIPH.

Diagnosis of pulmonary disease in athletic horses 
Renaud Leguillette, DVM, MSc, PhD, DACVIM, DACVSMR

Pulmonary diseases affecting athletic horses are often a challenge to diagnose because a mild decrease in lung function can have a dramatic effect on performance of these horses. This paper discusses the clinical signs and ancillary tests performed to diagnose noninfectious lung pathologies affecting athletic horses. Standardized techniques currently or under development to diagnose inflammatory airway disease and exercise-induced pulmonary hemorrhage are described.

How to work up and diagnose respiratory problems related to poor performance in Race and Western Horses
Mike Major, DVM, MS, DACVS

Dysfunction of the respiratory tract is a major cause of poor performance in the equine athlete. Respiratory function is the main constraining factor to maximal work level in the fit, sound horse and even mild upper airway obstruction or lung disease can markedly diminish performance.

How to work up poor performance related to underlying neurologic problems
Yvette S. Nout-Lomas, DVM, PhD, DACVIM, DACVECC

A thorough physical examination and gait evaluation, including lameness and neurologic examinations, are needed to identify which body system is most likely responsible for deficits. This paper provides some key elements to a diagnostic approach for a horse with poor performance in which neurologic disease is suspected.

Evaluation of videoendoscopic examinations of the upper respiratory tract in juvenile Thoroughbreds: Can we agree?
Sarah Plevin, BVMS, et al

Good inter- and intra-observer agreement for determining laryngeal grades using ordinal scales is lacking across all experience levels, independent of video-dependent variables. Observer agreement increased when ordinal scales were reclassified dichotomously.

How to determine if muscle disease is contributing to poor performance
Stephanie J. Valberg, DVM, PhD, DACVIM, DACVSMR

Poor performance can arise from sporadic focal muscle pain due to extrinsic sources as well as chronic generalized muscle pain and weakness from intrinsic sources. The foundation for determining the cause of pain or weakness is a thorough physical examination that integrates an orthopedic and neurologic examination with a systematic examination of the musculature.

How to approach epiglottic disorders in racing Quarter Horses in the field
Weston Warnock, DVM

This paper describes a practical approach for the racetrack or ambulatory practitioner to address select epiglottic disorders commonly encountered in racing Quarter Horses. Frequent and thorough endoscopic exams are important for diagnosis of causes of exercise intolerance, and may lead to early diagnosis and avoidance of chronic epiglottic conditions.

Session 7: These papers were referenced during the live virtual sessions on Tuesday, August 25.

Swing phase kinematics of horses trotting over poles
S. Brown, et al.

This paper compared limb kinematics in horses trotting over level ground, over low poles and over high poles to determine changes in joint angulations and hoof flight arcs.

Short-term habituation of equine limb kinematics to tactile stimulation of the coronet
Hilary M. Clayton, et al.

The purpose of this study was to evaluate short-term habituation to tactile stimulation of the pastern and coronet in trotting horses.

Evaluation of biomechanical effects of four stimulation devices placed on the hind feet of trotting horses
Hilary M. Clayton, et al.

This study compared effects of 4 types of stimulation devices attached to the hind feet on hoof flight, joint angles, and net joint powers of trotting horses.

Evaluation of intersegmental vertebral motion during performance of dynamic mobilization exercises in cervical lateral bending in horses
Hilary M. Clayton, et al.

This paper aims to identify differences in intersegmental bending angles in the cervical, thoracic, and lumbar portions of the vertebral column between the end positions during performance of 3 dynamic mobilization exercises in cervical lateral bending in horses.

A controlled study evaluating a novel surgical treatment for kissing spines in standing sedated horses
R.P.C. Coomer, et al.

This study compares the results of a novel minimally invasive surgical technique with intralesional corticosteroid medication, as treatment for overriding dorsal spinous processes (ORDSP) in horses.

A new technique for subtotal (cranial wedge) ostectomy in the treatment of impinging/overriding spinous processes: Description of technique and outcome of 25 cases
B.D. Jacklin, et al.

The aim of this paper was to evaluate whether subtotal (cranial wedge) ostectomy represents an effective treatment for overriding SPs, with short surgery time and low complication rates, maintains the contour of the spine and produces a functionally and cosmetically better outcome than previously reported surgical techniques for management of overriding/impinging SPs.

Segmental ostectomy of the second and fourth metacarpal and metatarsal bones in horses: 17 cases (1993-2002)
P.W. Jenson, et al.

The objective of this study was to determine clinical findings in and outcome of horses with fractures of the second or fourth metacarpal or metatarsal bone that underwent segmental ostectomy, leaving the proximal and distal portions of the bone undisturbed.

Long toes in the hind feet and pain in the gluteal region: An observational study of 77 horses
Richard Mansmann, et al.

This study deals with the relationship between long toes in the hind feet and pain in the gluteal region in horses, and the remedial value of trimming/shoeing that moves the breakover point back at the toe.

Clinical features, diagnostic imaging findings and concurrent injuries in 71 sport horses with suspensory branch injuries
D. Marneris, et al.

This retrospective study aimed to describe the limb and mediolateral distribution of suspensory ligament branch injuries, the case history of injured horses, clinical signs, response to diagnostic analgesia, presence of other injuries, ultrasonographic features, radiological abnormalities and outcome.

The relationship between sagittal hoof conformation and hindlimb lameness in the horse
Lynn Pezzanite, et al.

The objective of this study was to determine if there is an association between hoof balance in the sagittal plane and hindlimb lameness.

Dynamic mobilization exercises increase cross sectional are of musculus multifidus
Narelle C. Stubbs, et al.

Dynamic mobilization exercises may be a useful rehabilitative technique for horses in which m. multifidus has atrophied in response to back pain.

Extracorporeal shockwave therapy raises mechanical nociceptive threshold in horses with thoracolumbar pain
L.R. Trager, et al.

The purpose of this study was to evaluate effects of ESWT on spinal MNT and multifidus muscle CSA in horses with thoracolumbar pain.

Laser therapy for incision healing in 9 dogs
J.L. Wardlaw, et al.

Laser therapy is becoming common place in veterinary medicine with little evidence proving efficacy or dosages. This study evaluated surgical wound healing in canines.

Session 8: These papers were referenced during the live virtual sessions on Thursday, August 27.

Distribution of Injected Technetium99m-Labeled Mesenchymal Stem Cells in Horses with Naturally Occurring Tendinopathy
P. Becerra, et al.

This study aimed to investigate immediate cell survival and distribution following different administration routes of mesenchymal stem cells (MSCs) into naturally occurring tendon injuries

Immunoprivileged no more: Measuring the immunogenicity of allogeneic adult mesenchymal stem cells
A. Berglund, et al.

This review details what is currently known about the immunogenicity of allogeneic mesenchymal stem cells (MSCs) and suggests contemporary assays that could be utilized in future studies to appropriately identify and measure immune responses to major histocompatibility complex mismatched MSCs.

TGF -β2 decreases MHC I and MHC II expression on equine bone marrow-derived mesenchymal stromal cells
A. Berglund, et al.

The purposes of this study were to evaluate the effectiveness of exogenous TGFβ2 in 25 decreasing and stabilizing MHC expression on equine bone marrow-derived MSCs before and after IFNγ challenge; and to determine if exogenous TGFβ2 treatment would alter MSC multipotency as determined by tri-lineage differentiation assays.

Influence of temperature, time and different media on mesenchymal stromal cells shipped for clinical application
I. Bronzini, et al.

The impact of several experimental shipping conditions on the number of equine blood-derived (ePB-MSC) and canine adipose-derived (cA-MSC) MSCs were evaluated in this study.

Mechanisms involved in the therapeutic properties of mesenchymal stem cells
L. DaSilva, et al.

This paper identifies some of the molecules involved in the paracrine effects of mesenchymal stem cells with a perspective that these cells intrinsically belong to a perivascular niche in vivo and discusses how this knowledge could be advantageously used in clinical applications.

Magnetic resonance imaging findings in horses with septic arthritis
Jeremiah T. Easley, et al

Magnetic resonance imaging may allow earlier and more accurate diagnosis of septic arthritis in horses as compared with other imaging modalities, especially when the clinical diagnosis is challenging.

Equine or porcine synovial fluid as a novel ex vivo model for the study of bacterial free-floating biofilms that form in human joint infections
J.M. Gilbertie, et al

This paper describes the use of ex vivo equine and porcine models for the study of synovial fluid induced biofilm aggregate formation and antimicrobial tolerance.

Oral reserpine administration in horses results in low plasma concentrations that alter platelet biology
J.M. Gilbertie, et al.

This paper evaluated the pharmacokinetics of oral reserpine in horses and the effects of clinically relevant concentrations of reserpine on platelet functionality in vitro.

Platelet‐rich plasma lysate displays antibiofilm properties and restores antimicrobial activity against synovial fluid biofilms in vitro
J.M. Gilbertie, et al.

This study investigates the ability of platelet‐rich plasma (PRP) formulations to combat synovial fluid biofilm aggregates using an in vitro equine model.

Implantation of bone marrow-derived mesenchymal stem cells demonstrates improved outcome in horses with overstrain injury of the superficial digital flexor tendon
E. Godwin, et al.

The purpose of this study was to evaluate the safety and reinjury rate of racehorses after intralesional MSC injection in a large study of naturally occurring superficial digital flexor tendinopathy and to compare these data with those published for other treatments.

Conditioning equine athletes on water treadmills significantly improves peak oxygen consumption
Persephone Greco-Otto, et al.

The purpose of this study was to test the effect of an 18-day water treadmill conditioning program on peak oxygen consumption.

Ultrasound-guided proximolateral approach for digital flexor tendon sheath injection in the horse: A cadaver study
Caitlyn R. Horne, et al.

The aim of this study was to define a reliable ultrasound-guided proximolateral approach for injection of the digital flexor tendon sheath in horses that would be as accurate as the landmark-guided basilar sesamoidean approach.

Repeated intra-articular injection of allogeneic mesenchymal stem cells causes an adverse response compared to autologous cells in the equine model
A-J. Joswig, et al.

The objective of this study was to assess the clinical response to repeated intraarticular injection of allogeneic versus autologous MSCs prepared in a way to minimize xeno-contaminants in a large animal model.

The effect of autologous protein solution on the inflammatory cascade in stimulated equine chondrocytes
R.L. Linardi, et. al

The objective of this study was to quantify cytokine concentrations in autologous conditioned serum (ACS) and autologous protein solution (APS) and evaluate the protective effects of ACS and APS on inflamed chondrocytes cultured in vitro.

Optimization of leukocyte concentration in platelet-rich plasma for the treatment of tendinopathy
Tara M. McCarrel, et al

This study hypothesizes that leukocyte-reduced platelet-rich plasma (PRP) would result in lower inflammatory cytokine expression compared with concentrated-leukocyte PRP and that maintaining the platelet:white blood cell (WBC) ratio would compensate for the effect of increased WBC concentration.

The effect of four different freezing conditions and time in frozen storage on the concentration of commonly measured growth factors and enzymes in equine platelet-rich plasma over six months
A.K. McClain, et al.

The objectives of this study was to determine the effect of a single freeze-thaw cycle on platelet-rich protein (PRP) concentrations and establish their baseline levels and to evaluate the effect of storage in -20 °C automatic defrost freezer, − 20 °C manual defrost freezer, − 80 °C manual defrost freezer, and liquid nitrogen for 1, 3, and 6 months on PRP protein concentrations, compared to the established baseline concentrations.

Determination of weight reduction in horses in flotation tanks
S.A. McClintock, et al.

The primary aim of this paper is to reduce the effective weight supported by the horse’s limbs because of the necessity to reduce stress on the injured limb and prevent contralateral limb complications.

Water depth modifies back kinematics of horses during water treadmill exercise
K.J. Nankervis, et al.

The objective of this study was to measure the flexion‐extension range of motion (FE ROM) of the thoracolumbar spine and pelvic vertical displacement during water treadmill walking at 3 water depths and compare these with the control condition.

Equine allogeneic bone marrow-derived mesenchymal stromal cells elicit antibody responses in vivo
Lynn Pezzanite, et al.

This study tested the hypothesis that Major Histocompatibility Complex (MHC) incompatible equine mesenchymal stromal cells (MSCs) would induce cytotoxic antibodies to donor MHC antigens in recipient horses after intradermal injection.

B-mode and power Doppler ultrasonography of the equine suspensory ligament branches: A descriptive study on 13 horses
S. Rabba, et al.

The aim of this prospective, pilot study was to assess the presence or absence of power Doppler signal in suspensory ligament branches and compare B-mode findings with power Doppler findings in suspensory ligament branches of lame and non-lame limbs.

Therapeutic use of stem cells in horses: Which type, how, and when?
Lauren V. Schnabel, et al.

The purpose of this review was to provide contemporary information as to which type of stem cells should be used, how they should be applied, and when they should be applied for the treatment of clinical conditions.

Noninfected tenosynovitis of the digital flexor tendon sheath: A retrospective analysis of 76 cases
M.R.W Smith, et al.

Until recently, the pathogenesis of noninfected tenosynovitis of the digital flexor tendon sheath (DFTS) has been considered obscure. With the advent of tenoscopy some inciting causes have been described, but to date few cases with a precise diagnosis have been reported.

Distribution and persistence of technetium‐99 hexamethyl propylene amine oxime‐labelled bone marrow‐derived mesenchymal stem cells in experimentally induced tendon lesions after intratendinous injection and regional perfusion of the equine distal limb
A. Sole, et al.

This study hypothesized that vascular perfusion of the equine distal limb with mesenchymal stem cells (MSCs) would result in preferential distribution of MSCs to acute tendon injuries.

Ultrasound‐guided injection of the median artery in the standing sedated horse
Mathieu Spriet, et al.

The purpose of this study was to assess the feasibility of injection of the median artery in standing sedated horses.

Ultrasound‐guided injection of the cranial tibial artery for stem cell administration in horses
A. Torrent, et al.

The aim of this study was to assess the feasibility of injection of the cranial tibial artery in horses, and to evaluate the distribution and persistence of mesenchymal stem cells after injection.

Scintigraphic comparison of intra-arterial injection and distal intravenous regional limb perfusion for administration of mesenchymal stem cells to the equine foot
J.M. Trela, et al.

This study evaluates the distribution, uptake and persistence of radiolabelled mesenchymal stem cells after intra-articular injection through the median artery without a tourniquet and after intravenously regional limb perfusions through the lateral palmar digital vein.

Additional Resources

Physical therapy approach to the equine athlete
Sharon Classen, PT, CERP, et al.

The symbiotic interplay between horse and rider in equine sports is paramount and should not be overlooked. Factors including physical fitness, aerobic and anaerobic conditioning, strength, flexibility, proprioception, and other complex biomechanical factors that affect the rider will also affect the horse, and vice versa.

How to perform objective outcome measurements in equine rehabilitation
Melanie Connor, DVM, et al.

Equine rehabilitation programs are tailored toward each patient, their specific injuries, and associated comorbidities. Having reliable and consistent methods of measuring the outcomes of these programs are important to objectively monitor patient progress. The methods described in this paper provide numerical or pictorial data that provide evidence-based support to protocol design and development.

How does the imaging diagnosis dictate a rehabilitation program?
Erin K. Contino, DVM, MS, DACVSMR

Diagnostic imaging is critical in developing an appropriate rehabilitation program. Imaging characterizes the extent, severity, character, location and tissue type of the injury, all of which influence the treatment, exercise, and physical therapy regime.

Rehabilitation for soft tissue injuries
Erin K. Contino, DVM, MS, DACVSMR

The general guidelines for any rehabilitation protocol include decreasing pain and restoring proprioception, flexibility, strength, and endurance. There are a multitude of rehabilitation modalities and techniques that can be utilized to achieve these goals and to design a successful rehabilitation protocol.

Review of the development of effective rehabilitation protocols in horses
Kevin K. Haussler, DVM, DC, PhD, et al

Rehabilitation has become an important aspect of equine practice. Unfortunately, there is limited knowledge or awareness of the general principles and methods used to develop safe and effective rehabilitation programs. By following a few basic principles, appropriate rehabilitation programs can be developed for individual horses with a wide range of injuries and sources of musculoskeletal pain or dysfunction.

Equine rehab recap – Where are we now?
Melissa R. King, DVM, PhD, DACVSMR

This paper reviews various physical modalities and therapeutic exercises commonly employed in equine rehabilitation. Universal recommendations regarding the timing, frequency and specific indications of many modalities are still lacking. As further research is able to define specific parameters, significant advancements within the rehabilitation field can be expected.

Practical approach to the rehabilitation of soft tissue injuries in Sport Horses
Alan Manning, MSC, DVM

A successful rehabilitation requires an accurate diagnosis; a clear, concise written treatment and rehabilitation protocol; and regular evaluations of the injury and its progress. Every case is different and should be approached it that way.

Sport horse lameness and rehabilitation 
Tracy A. Turner, DVM, MS, DACVS, DACVSMR

Sport horse lameness is no different than any other lameness with the exception that it is probably more subtle. The sensitivity of the rider, driver, or trainer notices issues much sooner. These issues may be as simple as perceived loss of speed or other performance factor. An examination is critical and must be systematic and thorough.

Training and rehabilitation
Tracy A. Turner, DVM, MS, DACVS, DACVSMR

An effective rehabilitation program should utilize specific veterinary and physiotherapy interventions to ensure pain-free range of movement is achievable, alongside strength, balance, and proprioception training using clinically reasoned treatment protocols based upon evidence-based practice and a thorough knowledge of equine functional anatomy and biomechanics.