Nathalie Crevier-Denoix

Summary: Background: Equine cervicothoracobrachial syndrome (CTBS) has been shown as a cause of proximal forelimb lameness and dyskinesia in horses. Because of close anatomical relationships, arthropathies of the first costovertebral joint (CVJ1) may interfere with the ventral ramus of the eighth cervical nerve (C8N), the major root of the brachial plexus (BP). Objectives: To describe the ultrasonographic technique to image CVJ1 and C8N in field practice, to provide normal ultrasonographic images and present abnormalities seen in horses presenting a CTBS. Study design: The presentation is based on clinical cases referred for non‐blockable lameness or athletic difficulties. Methods: A regular 5–10 MHz macroconvex (curvilinear) ultrasound probe is used to examine CVBJ1 and CTJ1. After adequate preparation of the area, the forelimb is moved caudally to facilitate access to the two parts of the CVJ1: the costovertebral‐body joint, CVBJ1 (between the costal head of the first rib—R1 and costal foveas of the C7 and T1 vertebral bodies), and the costotransverse joint, CTJ1 (between R1 costal tuberculum and T1 transverse process). Results: Abnormalities identified in clinical cases include arthropathy of CVBJ1 and fracture of the costal head interfering with the cranial fibres of C8N. CTJ1 conditions include peri‐articular osteophytes, capsulitis, capsular enthesopathies and hypogenesis of R1 in contact with the caudal fibres of C8N or the BP itself. Main limitations: Deep bone lesions cannot be imaged with ultrasonography; interference between CTJ1 and the ventral ramus of the first thoracic spinal nerve are hidden by the first rib. Conclusion: Ultrasonography is presently the only imaging technique providing detailed discrimination of the soft tissues including nerves in the cervicothoracic area. The procedure can be done in the field on the standing horse. It provides an essential contribution to the understanding and management of many unexplained lameness in horses.

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The measurement of musculoskeletal tissue properties and loading patterns during physical activity is important for understanding the adaptation mechanisms of tissues such as bone, tendon, and muscle tissues, particularly with injury and repair. Although the properties and loading of these connective tissues have been quantified using direct measurement techniques, these methods are highly invasive and often prevent or interfere with normal activity patterns. Indirect biomechanical methods, such as estimates based on electromyography, ultrasound, and inverse dynamics, are used more widely but are known to yield different parameter values than direct measurements. Through a series of literature searches of electronic databases, including Pubmed, Embase, Web of Science, and IEEE Explore, this paper reviews current methods used for the in vivo measurement of human musculoskeletal tissue and describes the operating principals, application, and emerging research findings gained from the use of quantitative transmission-mode ultrasound measurement techniques to non-invasively characterize human bone, tendon, and muscle properties at rest and during activities of daily living. In contrast to standard ultrasound imaging approaches, these techniques assess the interaction between ultrasound compression waves and connective tissues to provide quantifiable parameters associated with the structure, instantaneous elastic modulus, and density of tissues. By taking advantage of the physical relationship between the axial velocity of ultrasound compression waves and the instantaneous modulus of the propagation material, these techniques can also be used to estimate the in vivo loading environment of relatively superficial soft connective tissues during sports and activities of daily living. This paper highlights key findings from clinical studies in which quantitative transmission-mode ultrasound has been used to measure the properties and loading of bone, tendon, and muscle tissue during common physical activities in healthy and pathological populations.

A randomized controlled trial was performed on racing horses, to evaluate the efficacy of a new class of therapeutic agents in regenerative medicine—ReGeneraTing Agents^® (RGTA^®), to treat tendinopathies. Preliminary uncontrolled studies on tendon healing in racing horses with RGTA^® (OTR4131)—Equitend^® showed encouraging results, justifying performing a randomized, controlled, multicenter study with a two-year racing performance follow up. The objective of this study was to evaluate the effect of Equitend^® versus placebo on acute superficial digital flexor tendonitis in racing French Standardbred Trotters (ST). Twenty-two ST were randomly and blindly assigned to receive with a ratio of 2 to 1, a single Equitend^® (n = 14) or placebo (n = 8) intralesional injection under ultrasonographic guidance. Horses were evaluated over 4 months, by clinical and ultrasonographic evaluations (day 0, months 1, 2, 4), and their racing performances followed up over the 2 years after treatment. During the first month of treatment, a significant decrease in the cross-sectional area (CSA) was found in the Equitend^® group (p = 0.04). After 4 months, the number of Equitend^® treated horses with an improved CSA was significantly higher than the placebo-treated horses (p = 0.03571). The Equitend^® group returned to their pre-injury performance level, racing in, and winning, significantly more races than the placebo group (p = 0.01399 and 0.0421, respectively). Furthermore, recurrence was significantly higher in the placebo group than in the Equitend^® group (71.4% vs 16.6%, p = 0.02442). In conclusion, we measured a significant, short-term, reduction effect on CSA and demonstrated a long-term beneficial effect of intralesional injection of Equitend^® for the treatment of superficial digital flexor tendonitis on racing ST, racing 2. 3 times more often than placebo, with 3.3 times fewer recurrences maintaining pre-injury performance level. This study may open the way for the development of a human treatment of tendonitis.

OBJECTIVE To evaluate the effect of track surface firmness on the development of musculoskeletal injuries in French Trotters during 4 months of race training. ANIMALS 12 healthy 3-year-old French Trotters. PROCEDURES Horses were paired on the basis of sex and body mass. Horses within each pair were randomly assigned to either a hard-track or soft-track group. The counterclockwise training protocol was the same for both groups. Surface firmness of each track was monitored throughout the training period. Radiography, ultrasonography, MRI, and scintigraphy were performed on all 4 limbs of each horse before and after 2 and 4 months of training. Lesions were described, and lesion severity was classified with a 5-point system, where 0 = no lesions and 4 = severe lesion. RESULTS 86 lesions were identified, of which 46 (53.5%) were classified as potentially clinically relevant (grade, ≥ 2). Of the 18 moderate and severe lesions, 15 were identified in horses of the hard-track group, and 10 of those were in forelimbs. Moderate to severe tendinopathy of the superficial digital flexor tendon of the forelimb developed in 3 of the 6 horses of the hard-track group but none of the horses of the soft-track group. Metatarsal condyle injuries were more frequent in horses of the hard-track group than horses of the soft-track group. Severe lesions were identified only in left limbs. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that track surface firmness is a risk factor for musculoskeletal injuries in horses trained for harness racing.

(2017). Comparison of peak vertical force and vertical impulse in the inside and outside hind limbs in horses circling on a soft surface, at trot and canter. Computer Methods in Biomechanics and Biomedical Engineering: Vol. 20, Société de Biomécanique Conference 2017, pp. 51-52.

(2017). Comparison between Clegg Impact Soil Tester and hoof impact shock measurements on 13 surfaces used for training trotters or sport horses. Computer Methods in Biomechanics and Biomedical Engineering: Vol. 20, Société de Biomécanique Conference 2017, pp. 145-146.

(2017). Ground reaction force and impulses of fore and hindlimbs in horses at trot on an asphalt track: effects of an inclined (uphill) compared to a flat surface. Computer Methods in Biomechanics and Biomedical Engineering: Vol. 20, Société de Biomécanique Conference 2017, pp. 143-144.

Introduction Achilles tendon rehabilitation protocols commonly recommend a gradual increase in walking speed to progressively intensify tendon loading. This study used transmission-mode ultrasound to evaluate the influence of walking speed on loading of the human Achilles tendon in vivo. Methods Axial transmission speed of ultrasound was measured in the right Achilles tendon of 33 adults (mean ± SD: age, 29 ± 3 yr; height, 1.725 ± 0.069 m; weight, 71.4 ± 19.9 kg) during unshod, steady-state treadmill walking at three speeds (slow, 0.85 ± 0.12 ms; preferred, 1.10 ± 0.13 m·s⁻¹; fast, 1.35 ± 0.20 m·s⁻¹). Ankle kinematics, spatiotemporal gait parameters and vertical ground reaction force were simultaneously recorded. Statistical comparisons were made using repeated-measures ANOVA models. Results Increasing walking speed was associated with higher cadence, longer step length, shorter stance duration, greater ankle plantarflexion, higher vertical ground reaction force peaks, and a greater loading rate (P < 0.05). Maximum (F_1,38 = 7.38, P < 0.05) and minimum (F_1,46 = 8.95, P < 0.05) ultrasound transmission velocities in the Achilles tendon were significantly lower (16–23 m·s⁻¹) during the stance but not swing phase of gait, with each increase in walking speed. Conclusions Despite higher vertical ground reaction forces and greater ankle plantarflexion, increasing walking speed resulted in a reduction in the axial transmission velocity of ultrasound in the Achilles tendon; indicating a speed-dependent reduction in tensile load within the triceps surae muscle–tendon unit during walking. These findings question the rationale for current progressive loading protocols involving the Achilles tendon, in which reduced walking speeds are advocated early in the course of treatment to lower Achilles tendon loads.