L’échographie des articulations, une révolution en pathologie locomotrice équine

Equine diagnostic ultrasonography was initially used for the diagnosis and documentation of tendon injuries. Since 1990, this technique became an essential complement to radiography for the diagnosis of equine joint lesions. Ultrasonography provides precise information on the synovial membrane and fluid, articular cartilage, subchondral bone, jointmargins, ligaments andmenisci, as well as on the anatomical structures involved in any periarticular thickening. With the improvement of ultrasound machines and image resolution, both in superficial and deep fields, all limb joints can now be examined, even the most proximal ones, as well as most axial joints of the equine spine, pelvis and head. Within two decades, a large number of new conditions of the equine locomotor systemhave been discovered using ultrasonography; this knowledge has deeply changed the diagnostic approach and understanding of lameness in horses. As professional athletes, horses provide an excellent animal model of spontaneous locomotor sport-induced injuries. The quality of imaging documentation is improved by the size of the anatomical structures being viewed. Strict standardization of the technical approach of every joint structure and accurate knowledge of the equine locomotor system anatomy are required to guarantee the sensitivity and specificity of diagnostic ultrasonography of joint injuries.D'abord utilisée pour le diagnostic et la documentation des lésions tendineuses, l'échographie est devenue depuis 1990 un complément indispensable à la radiologie dans le diagnostic des affections articulaires chez le cheval. Cette technique fournit des informations précises sur la membrane et le contenu synovial, le cartilage articulaire et l'os sous-chondral, les marges articulaires, les ligaments et les ménisques, ainsi que sur les formations impliquées lors d'épaississement péri-articulaire. L'amélioration des appareils et de la résolution de l'image, en régions superficielles comme en profondeur, permettent maintenant d'envisager l'examen de toutes les articulations des membres, y compris les plus proximales, et de la plupart des articulations axiales (colonne vertébrale, bassin et tête) du cheval. En 20 ans, un grand nombre d'entités pathologiques nouvelles ont été mises en lumière grâce à l'échographie; ces connaissances ont profondément changé l'approche diagnostique et la compréhension des boiteries chez le cheval. Athlète professionnel, le cheval constitue un excellent modèle animal de pathologie locomotrice sportive spontanée; la taille de ses formations anatomiques facilite et améliore la documentation lésionnelle par imagerie. L'échographie articulaire nécessite une codification stricte de l'abord technique de chaque formation et une connaissance précise de l'anatomie de l'appareil locomoteur du cheval, conditions indispensables pour garantir les performances de la technique en matière de sensibilité et de spécificité

Acoustodynamometry : An innovating non-invasive technique used to measure tendon load during movement

A novel technique was developed to measure the tendon load in people and in horses in motion. This non-invasive technique is based on a relation, demonstrated experimentally in vitro on isolated tendons and limbs, between the velocity of ultrasound in the tendon and the load to which it is subjected. A prototype was created to examine the equine superficial digital flexor tendon. The reproducibility of these measurements assessed in five horses was very good in a given subject, but marked differences were observed between the animals, in terms of plot shape and ultrasound velocity. These differences appeared directly related to the horse’s digital standing conformation. The technique thus validated was then used to examine the effect of four types of orthopaedic shoes compared to a standard shoe, on hard as well as soft ground.Un procédé original de mesure de la force qui s'exerce dans un tendon, chez le Cheval ou l'Homme en mouvement, a été mis au point. Cette technique non-invasive repose sur une relation, démontrée expérimentalement in vitro, sur tendons et membres isolés, entre la vitesse des ultrasons dans un tendon et la force qui s'applique sur celui-ci. Un prototype adapté au tendon fléchisseur superficiel du doigt du cheval a été réalisé. La reproductibilité des mesures, évaluée chez cinq chevaux, au pas et au trot, est très bonne chez un même individu, mais il existe des différences nettes entre sujets, à la fois dans la forme des tracés et dans les niveaux de vitesse des ultrasons observés. Ces différences sont apparues étroitement liées à l'aplomb digital des chevaux. Le procédé ainsi validé a permis d'évaluer l'effet de quatre types de ferrures correctrices, comparées à un fer standard, sur sol dur et sur sol meuble

Diagnostic imaging of equine thoracolumbar disorders

Equine thoracolumbar conditions represent a major cause of poor performance and locomotor disorders in sports and race horses. Advances in diagnostic imaging during the last 15 years allow today to diagnose most equine back lesions in the standing sedated horse. Radiography is the first choice imaging modality due to its high diagnostic performance. Ultrasonography is a complementary modality to further investigate back soft tissues and the caudal lumbar area not evaluable radiographically in the standing horse. Bone scintigraphy is a more complex and expensive technique and is usually dedicated to complicated clinical cases. The most frequent injuries diagnosed using these 3 modalities are kissing spines, osteo-arthrosis of the synovial intervetebral joints, vertebral spondylosis and muscle injuries. Clinical significance of these lesions should be interpreted with care considering the clinical signs exhibited by the horse but also its sports or racing useLes affections vertébrales thoracolombaires représentent une cause fréquente de baisse de performances et/ou de troubles locomoteurs chez les chevaux de sport et de courses. Le développement des techniques d’imagerie ces 15 dernières années permet aujourd’hui au vétérinaire équin de diagnostiquer un grand nombre de lésions affectant la colonne thoracolombaire sur le cheval debout tranquillisé. La radiographie du dos du cheval constitue la modalité d’imagerie de premier choix par sa capacité diagnostique élevée. L’échographie complète la radiographie dans l’exploration des tissus mous et de la région lombaire caudale, cette dernière n’étant pas accessible par radiographie sur le cheval debout. La scintigraphie, technique plus onéreuse et plus contraignante, est envisagée pour des cas cliniques complexes. Les lésions les plus fréquemment diagnostiquées avec ces techniques d’imagerie sont représentées par les conflits et fractures des processus épineux, les arthroses synoviales intervertébrales, les spondyloses vertébrales et les lésions musculaires. La signification clinique de ces lésions doit être évaluée en considérant les signes cliniques du patient mais également sa discipline sportiv

The Sequisol project: biomechanical eval uation of the effects of equestrian track surfaces on the equine locomotor system

The quality of ground surfaces conditions equine locomotion and can be a risk factor for osteoarticular and tendinous lesions. A novel protocol of biomechanical measurements has been developed to characterize the effects of ground surfaces on the locomotor system and locomotion of harnessed trotter horses under training conditions. This protocol is based on the simultaneous use of a 3D dynamometric horseshoe, a 3D accelerometer, a superficial digital flexor (SDF) tendon force ultrasonic sensor, inertial measurement units, and a high-speed camera. Three French trotters were used to compare two tracks at the Grosbois training centre (crushed sand and all-weather waxed track) ; biomechanical measurements were performed at a standardized speed (9.7 m/s, i.e. 35 km/h). The all-weather waxed track appeared as the most damping (shock absorbing), i.e. lesser impact deceleration and braking force and lesser maximal loading rate of the SDF tendon. However, the horse’s locomotor comfort (determined by the stride length) did not seem to be greater. The preliminary results of the tests performed since October 2006 as part of the Sequisol project (10 tracks tested on 5 different sites) confirm superior shock-absorbing properties as well as a “slower” characteristic during the braking phase for the all-weather waxed tracks, and generally speaking, the strong influence of maintenance conditions of the surfaces on the biomechanical results.La qualité du sol conditionne la locomotion d'un cheval, et peut aussi être un facteur de risque de lésions ostéo-articulaires et tendineuses. Un protocole original de mesures biomécaniques a été mis au point afin de caractériser l'effet des sols sur l'appareil locomoteur et la locomotion, chez le trotteur attelé, dans les conditions de l'entraînement. Ce protocole repose sur l'utilisation simultanée d'un fer dynamométrique 3D, d'un accéléromètre 3D, d'un capteur ultrasonore de force dans le tendon fléchisseur superficiel du doigt (perforé), de centrales de mesure inertielle et d'une caméra haute fréquence. Trois chevaux trotteurs français ont été utilisés pour comparer deux pistes du centre d'entraînement de Grosbois (sable concassé et sable fibré-huilé); les mesures biomécaniques ont été effectuées à vitesse standardisée (9,7 m/s, soit 35 km/h). La piste en fibré-huilé présente des propriétés d'amortissement plus importantes que la piste en sable concassé: la décélération à l'impact, la force de freinage et la vitesse de mise en tension maximale du tendon perforé sont plus faibles. En revanche, le confort locomoteur du cheval, apprécié notamment par la longueur de la foulée, n'est pas supérieur. Le bilan préliminaire des tests réalisés depuis octobre 2006 dans le cadre du projet Sequisol (dix pistes testées sur cinq sites différents) confirme le caractère plus amortissant mais aussi plus « lent », lors du freinage, des pistes en fibré-huilé et, plus généralement, l'influence forte des conditions d'entretien des sols sur les résultats biomécaniques

Interest of magnetic resonance imaging in the diagnosis of equine locomotor disorders

Magnetic Resonance Imaging (MRI) is the current gold standard in human medicine for locomotor apparatus imaging. This paper presents the interest of MRI in the diagnosis of equine locomotor disorders, based on patients examined at the CIRALE centre with a C-shape low-field system (0.2 T). The protocols used and indications of this technique are described. The diagnostic interest of MRI is then presented by anatomical entities. MRI is a very reliable technique to identify bone lesions which are radiologically invisible. Compared to ultrasonography, MRI provides images of all soft tissues in the foot, with greater tissue discrimination within the lesions. The downside, however, is that a general anesthesia is necessary to obtain diagnostic images of high quality. Moreover, current MRI systems are able to visualise only the distal segments of the limbs (including carpus and tarsus), the head, and the cervico-cranial hinge. The development of MRI systems designed to examine a standing horse is an interesting avenue of research, which would overcome these limitations.L'Imagerie par Résonance Magnétique (IRM) est aujourd'hui en médecine humaine la technique d'imagerie de référence pour l'appareil locomoteur. L'objectif de cet article est de présenter les apports de l'IRM dans le diagnostic des affections locomotrices du cheval à partir des patients examinés au CIRALE à l'aide d'une machine bas champ (0,2 T) avec une configuration en C. Les protocoles utilisés et les indications de cet examen sont décrits. Les apports de l'IRM au plan diagnostic sont ensuite présentés par type de formation anatomique. L'IRM permet notamment d'identifier, avec une grande fiabilité, des lésions osseuses qui ne sont pas visibles en radiographie. Elle présente, par rapport à l'échographie, la capacité d'imager l'ensemble des tissus mous du pied et permet une meilleure discrimination tissulaire au sein des lésions. En revanche, l'IRM requiert une anesthésie générale pour obtenir des images de grande qualité diagnostique. D'autre part, seules les régions distales des membres (jusqu'au carpe et tarse inclus), la tête et la région cervicale crâniale peuvent être examinées sur les machines actuelles. Pour pallier ces limites, le développement de machines IRM permettant l'imagerie sur cheval debout représente une voie de recherche intéressante

Morphology of the suspensory ligament (interosseous muscle III) of the horse

Introduction: The injuries of the suspensory ligament (SL) are important causes of lameness and financial losses in the equine industry. Ultrasound examination permitted to visualize some parts of the SL. The significance of “abnormal” findings is however not sufficiently known. Until now, few studies described the relationship between the ultrasonographic appearance and the exact morphology in histological sections. The aim of this study is to develop good techniques for cutting and staining the SL and to improve knowledge about the normal morphology of the SL. Methods: In this study, the SL of eight horses were collected. The body of the SL was divided in 3 thirds and sampling was realised within each third and between the thirds. The samples were embedded in paraffin or in Tissue-Tek for cryosections. The sections were stained with hematoxylin/eosin or Masson's trichrome. For 3 SL, ultrasounds were performed before sampling. The digital tip was maintained in physiological position owing to a press. Results: Most of the paraffin sections were shredded because of the hardness of the tissue. Cryosection revealed a better preservation of tissues. Only some freezing artifacts (holes) appeared on a few sections. Muscles fibers surrounded by adipose tissue containing blood vessels were present mainly in the proximal and medium third of the SL whereas they were not found in the distal third. The remaining structure look like a tendon and was composed of collagen fibers, stained in green with the Masson's trichrome coloration. Conclusions: This study permitted to develop cutting and staining techniques for the SL and helped to map the adipose, muscular and tendinous parts within the SL. It lays down the bases of subsequent studies that will concern ultrasonographically examined digital tips of sound and pathological horses of different breeds and ages

Findings and interobserver agreement in radiography and ultrasonography of the vertebral column of a large population of normally performing horses

Diagnostic imaging is a mainstay in the investigation of equine neck and back pain, but interpretation of radiographic and ultrasonographic findings in the spinal column of horses is not straightforward for a variety of reasons including individual anatomical variations, progressive degenerative nature of most pathologies and superimposition as well as technical limits. These issues are even more relevant in the context of examinations of apparently sound horses with absent, mild or unclear complaints, like it is often the case in pre-purchase examinations or cases of failure to meet expected performance. The first aim was to report on the spectrum, degree and location of first-line imaging findings in the spine of a large population of normally performing horses. Limited data is available about agreement of interpretation of equine vertebral column imaging by radiologists. The second aim of this prospective study was to determine interobserver agreement on radiographic and ultrasonographic diagnostic imaging findings in the vertebral column of the same population between multiple observers with longstanding experience in equine diagnostic imaging at two different institutions. Seventy-one horses randomly selected from a larger population of 250 normally performing horses participating in a swiss project on equine back health were examined at one referral center. Radiographic and ultrasonographic examinations were performed in a standardized fashion and images graded separately by two experienced radiologists at two different institutions. Focus was placed on osteoarthrosis of the synovial intervertebral articulations (SIVAs), impinging and overriding of the spinous processes (SPs) and spondylosis. Cohen’s weighted kappa was calculated for each pathology, location and segment in each modality. Interobserver agreement was calculated for findings at specific locations, single pathologies and single grades. Most horses showed no changes and were allocated grades 0 at most locations. Few abnormalities were found throughout the vertebral column, with clusters of abnormalities of the SIVAs in the caudal cervical segment and cranial lumbar segment as well as a cumulation of changes at the dorsal spinous processes in the caudal thoracic segment. These coincide with previously reported predilection sites of imaging findings in symptomatic populations. Overall mean value of agreement for imaging findings was moderate (k= 0.7). Agreement was moderate for imaging findings regarding the synovial intervertebral articulations of the thoracolumbar spine in radiography (k=0.66) but weak in ultrasonography (k=0.58). There was moderate agreement in the imaging findings of the cervical spine in ultrasonography (k=0.61) as well as radiography (k=0.62). Strong agreement was found in the radiographic assessment of changes of the thoracolumbar spinous processes (k=0.80). Almost perfect agreement was found in the radiographic assessment of thoracolumbar spondylosis (k=0.95). Agreement between radiologists in detection and grading of pathologies of the equine vertebral column is weak to almost perfect depending on pathology and location. Our results confirm findings about distribution of specific pathologies found in other studies and support the importance of interpreting imaging findings along with clinical findings for definitive case management and decision making. Additional studies are needed for determination of the correlation of imaging findings among different modalities and correlation of diagnostic imaging with clinical findings

Morphological and morphometric analyses of the suspensory ligament in Standardbreds

Ultrasound techniques allow examination of some parts of the suspensory ligament (SL) but "anomalies" are regularly observed. Their significance is not known. Few studies have described the relationship between ultrasonographic appearance and the exact morphology in histological sections. The aim of this study is to develop good techniques for cutting, staining, and showing the variation in the tissue composition within the SL. The SLs from the right limbs of 11 horses were collected. Samples were taken from cross-sections at six levels of the SL and they were embedded in paraffin or in Tissue-Tek®. Most of the paraffin sections were shredded. By using the cryosection technique, some freezing artifacts (holes) appeared. Therefore, a technique of freezing with cryoprotection was carried out, which produced the best results. Hematoxylin-phloxine-saffron gives a good contrast of colors between the tissues observed allowing the use of an image analysis program. The percentage of each tissue within the SL for each section and for six levels of the ligament was calculated. Results were analyzed by SAS software. The muscle tissue (PMT) and adipose tissue (PAT) decreased significantly (p < 0.0001), whereas the connective tissue (PCT) increased significantly (p < 0.0001) with age and when descending from the proximal to the distal level of the SL. The PMT was significantly higher (p < 0.0001) in females than males, while the PCT was significantly higher (p < 0.0001) in males than females. The PAT was significantly higher (p = 0.0278) in hindlimbs than in forelimbs

Morphometric analyses of the normal suspensory ligament in Standardbreds

The suspensory ligament (SL) is composed of connective tissue (CT) with a variable proportion of muscle (MT) and adipose tissue (AT). The aim of our study is to quantify the CT, MT and AT within the SL in sound horses. Right limbs from 11 horses were collected. Samples from 6 levels of the SL were embedded in paraffin or in Tissue-Tek®. Most of the paraffin sections were shredded. Using the cryosection, some artefacts appeared. Cryoprotection was carried out, which produced the best results. Hematoxylin–phloxine–saffron and Hematoxylin–eosin gave a good contrast of colours between the tissues allowing the use of an image analysis programme. The percentage of MT and AT decreased significantly (P < 0.0001), whereas the percentage of CT increased significantly (P < 0.0001) with age and when descending from the proximal to the distal level of the SL. The percentage of MT was significantly higher (P < 0.0001) in females than males, while the percentage of CT was significantly higher (P < 0.0001) in males than females. The percentage of AT was significantly higher (P = 0.0278) in pelvic limbs than in thoracic limbs. These results confirm the variation in tissue composition within the SL of sound horses