Hindlimb response to tactile stimulation of the pastern and coronet

Rehabilitation Strategies for the Neurologic Horse

Rehabilitation of the neurologic horse represents a unique challenge for the equine practitioner. Improving postural stability and balance control through improving the strength of the spinal stabilizer muscle multifidus remains one of the most promising rehabilitative targets. This muscle can be targeted through the use of physiotherapeutic exercises, various forms of perturbation, and even whole-body vibration. Neuroanatomic localization and diagnosis specificity enable the practitioner to determine suitability for such rehabilitative tasks, and with the advent of evolving strategies and commercially available equipment, the bandwidth for professionally guided programs is continuously being developed and is expected to improve traditional outcomes.

Effects of sand, asphalt and 3-degree hind toe or heel elevation on horse kinematics

BACKGROUND

Although the effects of both the surfaces and plantar angles on equine locomotion have been widely discussed, limited scientific data are available.

METHODS

Our objectives were to determine the effects of two surfaces (asphalt and sand) and of 3-degree hind toe or heel elevation on horse kinematics in an experimental study. Six saddle horses were shod with a reference shoeing (REF), characterized by a fore aluminium (REF F) and hind steel racehorse (REF H) shoeing. Two dimensional kinematic videos compared horse's kinematic parameters when walking and trotting on asphalt and sand. On asphalt, REF was also compared with REF F and a modified REF H with additional 3-degree hind-toe or -heel wedges.

RESULTS

On asphalt versus sand, horses had, at the trot, a shorter stride duration and forelimb maximal retraction, and at walk and trot, a greater fetlock, carpus, elbow and tarsus extension, a greater fore and hind limbs maximal protraction and a shorter hind limbs maximal retraction. Increasing the plantar angle decreased the tarsus and hind fetlock extension, in contrast to fore-limb, on asphalt during the stance phase.

CONCLUSIONS

These findings could be useful to adapt rehabilitation programs related to fore and hind limb pathologies, at slow gaits.

Equine Rehabilitation: A Scoping Review of the Literature

Simple Summary

When a horse is diagnosed with a locomotor disorder, the veterinarian treats the specific injury to restore the horse to soundness. Even after the injury has healed, however, the horse may not be fully functional due to persistent limitations in movement or strength in specific areas of the body. As in people, rehabilitation seeks to optimize function and reduce any existing disability using a variety of methods including manual therapy, the use of physical and mechanical agents, and specialized exercise regimes. This study has reviewed the scientific literature with the goal of identifying which types of physical therapy have been described in horses over the past 20 years. The most frequently reported techniques were exercise, electrotherapy, and hydrotherapy but there are relatively few publications describing details of their use and outcomes in clinical cases. This study reviews the methodology and outcomes of rehabilitation in clinical cases. The results highlight the paucity of clinically-based reports on the practical applications of equine rehabilitation and physical therapy.

Abstract

Injuries to the locomotor system are a common problem in athletic horses. Veterinarians address these injuries using appropriate medical, surgical, and pharmacological treatments. During or after recovery from the initial injury, horses may be treated for functional locomotor deficits using specific rehabilitation techniques aimed at restoring full athletic performance. This study reviews the literature to identify which rehabilitative techniques have been used most frequently in horses over the past 20 years, the protocols that were used, and the outcomes of the treatments in naturally occurring injuries and diseases. Publications were identified using keyword selection (Equine Athlete OR Equine OR Horse) AND (Rehabilitation OR Physiotherapy OR Physical Therapy). After removing duplicates and screening papers for suitability, 49 manuscripts were included in the study. The majority of publications that met the inclusion criteria were narrative reviews (49%) in which the authors cited the relatively small number of published evidence-based studies supplemented by personal experience. Observational/descriptive studies were also popular (35%). Randomized control trials accounted for only 10%. The most frequently reported rehabilitation techniques were exercise, electrotherapy, and hydrotherapy. The findings highlight the need for further information regarding type of intervention, parameterization, and outcomes of equine rehabilitation in clinical practice.

Water treadmill exercise reduces equine limb segmental accelerations and increases shock attenuation

BACKGROUND

Equine water treadmills (WTs) are growing in popularity because they are believed to allow for high resistance, low impact exercise. However, little is known about the effect of water height on limb loading. The aim of this study was to evaluate the effect of water height and speed on segmental acceleration and impact attenuation during WT exercise in horses. Three uniaxial accelerometers (sampling rate: 2500 Hz) were secured on the left forelimb (hoof, mid-cannon, mid-radius). Horses walked at two speeds (S1: 0.83 m/s, S2: 1.39 m/s) and three water heights (mid-cannon, carpus, stifle), with a dry WT control. Peak acceleration of each segment was averaged over five strides, attenuation was calculated, and stride frequency was estimated by the time between successive hoof contacts. Linear mixed effects models were used to examine the effects of water height, speed, and accelerometer location on peak acceleration, attenuation and stride frequency (p < 0.05).

RESULTS

Peak acceleration at all locations was lower with water of any height compared to the dry control (p < 0.0001). Acceleration was reduced with water at the height of the stifle compared to mid-cannon water height (p = 0.02). Water at the height of the stifle attenuated more impact than water at the height of the cannon (p = 0.0001).

CONCLUSIONS

Water immersion during treadmill exercise reduced segmental accelerations and increased attenuation in horses. WT exercise may be beneficial in the rehabilitation of lower limb injuries in horses.

The Efficacy of Intermittent Long-term Bell Boot Application for the Correction of Muscle Asymmetry in Equine Subjects

It has been proposed that manipulating proprioceptive signals of the equine distal limb as part of a rehabilitation process in cases of musculoskeletal pain or neurologic deficits can be used to correct postural control and restore normal motor programs. This trial has examined the effect of treatment with a light-weight and loose-fitting bell boot (82 g) on an imbalance of muscle gluteus superficialis function in horses as measured using acoustic myography (AMG). Eight horses were trained over a 60-minute period every 3 days for 6 weeks, a protocol based on preliminary findings. Acoustic myography measurements, recording the coordination, spatial and temporal summation of muscle contractions, were made at the start (baseline) and at the finish (week 6) after a warmup period and following a set procedure of physical activity. Walking, trotting, and cantering during a left-hand circle at the start of the trial revealed a slight but significant asymmetry between the left and right hind limb muscle, which improved successfully after 6 weeks of proprioception training. Data for the right-hand circle, which revealed no significant asymmetry, during walk, trot, and canter at the start, showed no change after 6 weeks of training at the walk and trot but developed an imbalance during cantering, the result of overcompensation. This study demonstrates that functional musculoskeletal asymmetry measured during periods of activity can not only be accurately detected using AMG but it also reveals an association between the program of proprioceptive training adopted and an improvement in muscular imbalance.

Introduction to Equine Physical Therapy and Rehabilitation

Physical therapy (physiotherapy, or PT) can be broadly defined as the restoration of movement and function and includes assessment, treatment, and rehabilitation. This review outlines the history, definition, and regulation of PT, followed by the core scientific principles of PT. Because musculoskeletal physiotherapy is the predominant subdiscipline in equine PT, encompassing poor performance, back pain syndromes, other musculoskeletal disorders, and some neuromuscular disorders, the sciences of functional biomechanics, neuromotor control, and the sensorimotor system in the spine, pelvis, and peripheral joints are reviewed. Equine PT also may involve PT assessment and treatment of riders.

Swing phase kinematics of horses trotting over poles

REASONS FOR PERFORMING STUDY

Trotting over poles is used therapeutically to restore full ranges of limb joint motion. The mechanics of trotting over poles have not yet been described, hence quantitative evidence for the presumed therapeutic effects is lacking.

OBJECTIVES

To compare 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.

STUDY DESIGN

Repeated measures experimental study in sound horses.

METHODS

Standard motion analysis procedures with skin-fixed reflective markers were used to measure swing phase kinematics from 8 horses trotting on level ground, over low (11 cm) and high (20 cm) poles spaced 1.05 ± 0.05 m apart. Spatiotemporal variables and peak swing phase joint flexion angles were compared using repeated measures ANOVA (P<0.05) with Bonferroni correction for pairwise post hoc testing.

RESULTS

Peak heights of the fore and hind hooves increased significantly and progressively from no poles (fore: 13.8 ± 3.8 cm; hind: 10.8 ± 2.4 cm) to low poles (fore: 30.9 ± 4.9 cm; hind: 24.9 ± 3.7 cm) and to high poles (fore: 41.0 ± 3.9 cm; hind: 32.7 ± 4.0 cm). All joints of the fore- and hindlimbs contributed to the increase in hoof height through increased swing phase flexion. The hooves cleared the poles due to increases in joint flexion rather than by raising the body higher during the suspension phases of the stride.

CONCLUSIONS

The increases in swing phase joint flexions indicate that trotting over poles is effective for activating and strengthening the flexor musculature. Unlike the use of proprioceptive stimulation devices in which the effects decrease over time due to habituation, the horse is required to elevate the hooves to ensure clearance whenever poles are present. The need to raise the limbs sufficiently to clear the poles and place the hooves accurately requires visuomotor coordination, which may be useful in the rehabilitation of neurological cases. The Summary is available in Chinese - see Supporting information.

Impact of walking surface on the range of motion of equine distal limb joints for rehabilitation purposes

The aim of this study was to evaluate the effect of three footing surfaces on the flexion/extension, and range of motion (ROM) of the carpus, tarsus and fetlocks in the horse. The percentage of stride spent in the stance phase of sound horses at the walk was also measured. Nine sound horses were walked on hard ground (HD), soft ground (SF) and a land treadmill (LT), and five complete gait cycles were recorded by a digital video camera. Retro-reflective markers were placed on the skin at four anatomical locations on the left fore and hind limbs, and data were analyzed using two-dimensional (2D) motion-analysis software. Maximal flexion/extension angles and range of motion were calculated for each joint, and the percentage of the stride spent in stance phase was determined for each stride. Maximal flexion of the tarsus and hind fetlock was greater on LT and SF compared to HD, while maximal flexion of the carpus was greater on LT compared to HD and SF. Maximal extension of the carpus was greater on HD compared to SF and LT, maximal extension of the tarsus was greater on HD and SF compared to LT, and maximal extension of the forelimb and hind limb fetlocks was greater on LT compared to HD and SF. The greatest overall ROM of the carpus and fetlocks was achieved on LT, while the greatest overall ROM of the tarsus was achieved on SF. The stance percentage of the stride for the hind limb was significantly different between all surfaces. In conclusion, walking surface influences flexion/extension of the carpus, tarsus and fetlocks in healthy horses, which should be considered when walking equine rehabilitation cases.

Effect of water depth on amount of flexion and extension of joints of the distal aspects of the limbs in healthy horses walking on an underwater treadmill

OBJECTIVE

To determine the maximum amount of flexion and extension of the carpal, tarsal, metacarpophalangeal, and metatarsophalangeal joints and the percentage duration of the stance and swing phases of the stride for horses walking on an underwater treadmill in various water depths.

ANIMALS

9 healthy adult horses.

PROCEDURES

Zinc oxide markers were placed on the forelimbs and hind limbs of the horses. Video was recorded of horses walking (0.9 m/s) on an underwater treadmill during baseline conditions (< 1 cm of water) or in various amounts of water (level of the metatarsophalangeal, tarsal, and stifle joints). Maximum amount of joint flexion and extension, range of motion (ROM), and the percentage durations of the stance and swing phases of the stride were determined with 2-D motion analysis software.

RESULTS

The ROM was greater for all evaluated joints in any amount of water versus ROM for joints in baseline conditions (primarily because of increases in amount of joint flexion). The greatest ROM for carpal joints was detected in a tarsal joint water depth, for tarsal joints in a stifle joint water depth, and for metacarpophalangeal and metatarsophalangeal joints in metatarsophalangeal and tarsal joint water depths. As water depth increased, the percentage durations of the stance and swing phases of the stride significantly decreased and increased, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of this study suggested that exercise on an underwater treadmill is useful for increasing the ROM of various joints of horses during rehabilitation and that the depth of water affects the amount of flexion and extension of joints.

Evaluation of biomechanical effects of four stimulation devices placed on the hind feet of trotting horses

OBJECTIVE

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

ANIMALS

8 clinically normal horses.

PROCEDURES

Horses were evaluated under 5 conditions in random order: no stimulators, loose straps (10 g), lightweight tactile stimulators (55 g), limb weights (700 g), and limb weights with tactile stimulators (700 g). Reflective markers on the hind limbs were tracked during the swing phase of 6 trotting trials performed at consistent speed to determine peak hoof heights and flexion angles of the hip, stifle, tarsal, and metatarsophalangeal joints. Inverse dynamic analysis was used to calculate net joint energies. Comparisons among stimulators were made.

RESULTS

Peak hoof height was lowest for no stimulators (mean ± SD, 5.42 ± 1.38 cm) and loose straps (6.72 ± 2.19 cm), intermediate for tactile stimulators (14.13 ± 7.33 cm) and limb weights (16.86 ± 15.93 cm), and highest for limb weights plus tactile stimulators (24.35 ± 13.06 cm). Compared with no stimulators, net tarsal energy generation increased for tactile stimulators, limb weights, and limb weights plus tactile stimulators, but only the weighted conditions increased net energy generation across the hip joint.

CONCLUSIONS AND CLINICAL RELEVANCE

The type and weight of foot stimulators affected the magnitude of the kinematic and kinetic responses and the joints affected. These findings suggest that different types of foot stimulators are appropriate for rehabilitation of specific hind limb gait deficits, such as toe dragging and a short stride.

Equine back pain reviewed from a motor control perspective

Back pain is recognized as a common and often recurrent problem in people and horses. Although there are many inciting causes of back pain, these often lead to a common pathway involving changes in neuromotor control and neurogenic atrophy of m. multifidi. The multi-layered and multi-directional fibres of this muscle stabilize the intervertebral joints in the face of bending and torsional moments. Inactivation and atrophy result in spinal instability and micromotion of the joints that predispose to further injury and degenerative changes, thus setting the scene for recurrent episodes of back pain. This review explores similarities between human and equine back pain, especially with regard to pathophysiology and prevention.

Swing phase kinematic and kinetic response to weighting the hind pasterns

REASONS FOR PERFORMING STUDY

It is considered that specific exercises to strengthen limb musculature would be helpful.

OBJECTIVE

To describe swing phase kinematic and kinetic changes in the hindlimbs of trotting horses in response to the addition of leg weights to the hind pasterns.

METHODS

Six horses were prepared by placing reflective skin markers on the hindlimbs, the withers and fore hooves. Horses were evaluated at trot for 6 trials with and without leg weights (700 g) attached around the pasterns, with the 2 conditions applied in random order. The markers were tracked to determine peak heights of the flight arc of the hind hooves and swing phase joint angulations. Inverse dynamic analysis was used to calculate positive and negative work done across each joint in the first and second halves of the swing phase. Comparisons between conditions were made using paired t tests (normally distributed data) or the Wilcoxon rank-sum test (non-normally distributed data).

RESULTS

Peak height of the flight arc of the hind hooves was significantly higher with leg weights as a result of increased flexions of the stifle, tarsal and metatarsophalangeal joints. Increased positive (concentric) work was performed by the hip and tarsal musculature to protract and raise the limb in early swing, then to retract and lower the limb in late swing. Increased negative (eccentric) work was performed across the stifle and metatarsophalangeal joints to control their movements in response to increases in inertia and momentum due to the weights.

CONCLUSIONS

The addition of weight to the hind pasterns stimulates increased muscular activity across all the hindlimb joints from the hip to the metatarsophalangeal joint.

CLINICAL SIGNIFICANCE

The addition of weight to the hind pasterns may have therapeutic applications in activating and strengthening the hindlimb musculature. This is particularly relevant in the hip region, which appears more sensitive and responsive to the effect of weights than to tactile stimulation alone.