In vitro evaluation of nonrigid support systems for the equine metacarpophalangeal joint

The influence of the metacarpophalangeal joint angle on the transversal area and mean echogenicity of the superficial digital flexor tendon and suspensory ligament in gaited horses

The objective of this study was to assess the influence of the metacarpophalangeal (MCP) joint angle on the transversal area (TA) and mean echogenicity (ME) of the superficial digital flexor tendon (SDFT) and suspensory ligament (SL) in gaited horses. Ultrasound images were obtained from 50 healthy adult horses of the Mangalarga Marchador (MM; n=25) and Campeiro (n=25) breeds. Static and dynamic angles of the MCP joint were measured from photographs and video recordings. Higher ME values were evinced for the SL only in the group with the smaller dynamic angles of the MCP joint in the MM horses, in addition to weak negative correlation between the dynamic angle and ME. Moreover, weak negative correlation was also observed between the static angle and TA of the lateral branch of the SL and between the static angle and the ME of the SDFT. However, the difference observed in the group of MM horses, as well as the weak correlation, was not considered sufficient to support the hypothesis that a smaller angle of the MCP joint (greater extension) is associated with larger TA and ME values for the structures. The results also suggest that the static and dynamic angles of the MCP joint do not influence the TA and ME values of the SDFT and SL in gaited horses.

Kinematic Analysis During Straight Line Free Swimming in Horses: Part 1 - Forelimbs

Background: Swimming is used for rehabilitation and conditioning purposes in equine sports medicine despite the lack of understanding of equine swimming kinematics. The aim of this study was to assess forelimb joints kinematics (elbow, carpus, and fetlock) in swimming horses. The specific objectives were 1- to calculate and compare joint angles in swimming vs. passive mobilizations (PM), 2- to determine joint angular velocities during a swimming stride cycle. Methods: Eleven elite endurance horses swam in a 100-m straight pool. Underwater (swimming) and overground (PM) videos were recorded from the horses' left side. Joint markers were applied on the lateral hoof wall, lateral metacarpal epicondyle, ulnar carpal bone, lateral humeral epicondyle, and the greater tubercle of humerus, from which elbow, carpus and fetlock angles, and angular velocities were obtained. As a reference, maximal fetlock, carpus, and elbow flexion/extension angles were determined during PM overground. Differences between angle extrema, angular velocities and range of motion (ROM) were compared. Results: Carpus and fetlock ROM were significantly smaller (p < 0.001) during swimming when compared with PM, while there was no difference in elbow ROM between both situations. The carpus had the greatest ROM of all joints during swimming. Absolute angular velocities values of all joints during swimming were greater during retraction than protraction (p < 0.001). When compared to other joints during protraction, the carpus joint reached the highest angular velocity. Conclusion: Swimming, as a rehabilitation exercise, has the potential to benefit horses where great elbow ROM with a moderate carpus and fetlock extension are wanted.

Mechanical Effect of Performance Pressure Boots on Cadaveric Equine Hindlimb Fetlock Biomechanics

Simple Summary

Pressure boots are performance enhancing equipment used by showjumping horses. Showjumping is scored by knocked down obstacle rails and time. Similar to weighted boots, pressure boots are intended to improve the hindlimb retraction of jumping horses to reduce the likelihood of knocking down rails on course. Manufacturers describe pressure boots as using acupressure to improve a horse’s awareness of their own limbs. However, this mechanism has not been verified within the scientific literature. The size and shape of features on the interior boot surface suggest a mechanical mechanism may affect anatomical structures within the lower limb. This research aims to characterize the mechanical effect of pressure boots by measuring forces and joint angles of cadaveric limbs with and without a pressure boot applied. Cadaveric limbs with a pressure boot applied required greater compressive loads to flex the fetlock joint than limbs without a pressure boot applied. This difference in compressive loads increased with increasing fetlock flexion angle. Differences in limb compressive loads contributed to greater tensile loads of palmar tendons and ligaments, specifically the suspensory apparatus. Greater tensile loading of tendons and ligaments may increase the likelihood of musculoskeletal injury and warrant concern for animal welfare of equine showjumping athletes.

Abstract

Pressure boots are applied to hind limbs of showjumping horses with the intent to enhance jumping form. Manufacturers claim acupressure points enhance proprioception of hind limbs. With this increased awareness, horses are expected to retract their hind limbs to clear jump rails. This research aimed to investigate a more direct, mechanical effect of pressure boots on hind limb biomechanics. Cadaveric hind limbs (n = 6) were mechanically loaded in axial compression (3 cycles at 0.25 Hz, displacement control ~3300 N) with (2 trials) and without (2 trials) a pressure boot applied. During mechanical loading, fetlock angle was measured using bone fixed pins with retroreflective markers (30 Hz). Changes in limb load and fetlock angle between unloaded and loaded states, as well as average fetlock joint stiffness, were compared between trials with and without the pressure boot via ANOVA. Differences in measured loads between trials with and without the boot were observed in both unloaded (Δ = 6 N, p = 0.05) and loaded states (Δ = 25 N, p = 0.002). Trials with the boot had greater average fetlock stiffness (Δ = 3 N/degree, p = 0.001). Differences in loads with and without boots may increase with greater fetlock angles when cantering and jumping. These mechanical effects of pressure boots may contribute to greater tensile loading of palmar tendons and ligaments, and likelihood of musculoskeletal injury that can be related to animal welfare issues.

Effect of parasitic infestation on carpal synovial constituents in donkeys (Equus asinus)

The present study was carried out to examine the physical, microscopical and biochemical parameters of the synovial fluid from the carpal joints of donkeys suffering from Strongylus spp. and Parascaris equorum infestation. Forty-five donkeys were selected out from a total of sixty animals based on faecal analysis. Animals were divided into 3 groups, which included Strongylus spp. (n=23), mixed infestation (n=17, Strongylus spp. and Parascaris equorum) and control (n=5) groups. The aspirated synovial fluid from all animals (n=45) was examined physically and microscopically. Then, the total protein, albumin, globulins, calcium, phosphorus, magnesium, glucose levels, and gamma glutamyl transferase (GGT) and alkaline phosphatase (ALP) activities were measured in the serum and synovial fluid of all animals. The results revealed no changes of the physical and microscopical features of the synovial fluid of the infested and control animals but there were significant decreases in total protein, albumin, globulin, glucose and magnesium levels in the serum of Strongylus and mixed infection groups. The synovial fluid analysis exhibited an increase of calcium and phosphorus levels, and ALP activity, and decreased levels of total protein, glucose and GGT in Strongylus and mixed groups. The results of this study suggested significant changes in some biochemical parameters in both serum and synovial fluids in donkeys suffering from parasitic infestation.

Biomechanical and wearability testing of novel legwear for variably limiting extension of the metacarpophalangeal joint of horses

OBJECTIVE

To evaluate the ability of novel legwear designed to limit extension of the metacarpophalangeal joint (MCPJ) to redirect loading forces from the flexor apparatus during walk, trot, and canter on a treadmill and during unrestrained and restrained activity in a stall.

ANIMALS

6 adult horses without musculoskeletal disease.

PROCEDURES

Legwear-derived force data were recorded under 4 conditions: inactive state (unlimited legwear extension) and 3 active (restrictive) states (mild, 30° extension; moderate, 20° extension; or maximum, 10° extension). Associations between peak legwear loads and torques among legwear states and treadmill gaits and stall activities were assessed. The hair coat and skin of the forelimbs were examined for any legwear-induced adverse effects after testing.

RESULTS

During the treadmill exercises, moderate restriction of legwear extension resulted in significantly higher peak load and torque than mild restriction, and faster speeds (canter vs walk or trot and trot vs walk) yielded significantly higher peak load and torque. During in-stall activity, maximum restriction of legwear extension yielded significantly higher peak load and torque than moderate restriction. Unrestrained in-stall activity resulted in significantly higher peak load and torque than restrained activity. The legwear caused minimal adverse effects on the hair coat and skin of the forelimbs.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings suggested that the legwear variably reduced peak loads on the flexor apparatus. Extension of the MCPJ may be incrementally adjusted through the legwear such that return to activity may be controlled, and controlled return to activity is crucial for rehabilitating flexor apparatus injuries.

Kinematic and kinetic analyses of the gait of horses wearing novel legwear for variably limiting extension of the metacarpophalangeal joint

OBJECTIVE

To investigate the effects of novel legwear designed to limit metacarpophalangeal joint (MCPJ) extension and redirect loading forces from the flexor apparatus through analyses of 2-D kinematic and kinetic data.

ANIMALS

6 adult horses without musculoskeletal disease.

PROCEDURES

Horses were subjected to 4 treatments: control (no legwear), inactive legwear (unlimited legwear extension), and active legwear with mild (30°) and moderate (20°) legwear extension limitation. Two-dimensional kinematic data were collected for the right forelimb (FL) during walk and trot and from leading and trailing FLs during canter on a treadmill. Ground reaction force (GRF) data were collected from FLs during overground walk and trot. Peak MCPJ angle and angular velocity were calculated from kinematic data, and peak force and average loading rate were calculated from vertical GRF data during the stance phase of the gait. Interactions between gait and treatment were determined via ANOVA.

RESULTS

Interactions between gait and treatment for peak MCPJ angle were significant. Significant reductions in MCPJ angle were noted between the control treatment and legwear with moderate extension limitation for trot and canter (leading and trailing FL) and between inactive legwear and legwear with moderate extension limitation for trot and leading FL during canter. Interactions among peak MCPJ angular velocity, peak vertical GRF, and average loading rate of the vertical GRF showed nonsignificance.

CONCLUSIONS AND CLINICAL RELEVANCE

Significant reductions in MCPJ extension without significant alterations to peak vertical GRF suggested the legwear's ability to redistribute internal forces. Findings suggested that the legwear may be beneficial for horses rehabilitating from flexor apparatus injuries.

Three-dimensional kinematics of the equine metacarpophalangeal joint using x-ray reconstruction of moving morphology – a pilot study

X-ray reconstruction of moving morphology (XROMM) uses biplanar videoradiography and computed tomography (CT) scanning to capture three-dimensional (3D) bone motion. In XROMM, morphologically accurate 3D bone models derived from CT are animated with motion from videoradiography, yielding a highly accurate and precise reconstruction of skeletal kinematics. We employ this motion analysis technique to characterize metacarpophalangeal joint (MCPJ) motion in the absence and presence of protective legwear in a healthy pony. Our in vivo marker tracking precision was 0.09 mm for walk and trot, and 0.10 mm during jump down exercises. We report MCPJ maximum extension (walk: –27.70 ± 2.78° [standard deviation]; trot: –33.84 ± 4.94°), abduction/adduction (walk: 0.04 ± 0.24°; trot: –0.23 ± 0.35°) and external/internal rotations (walk: 0.30 ± 0.32°; trot: –0.49 ± 1.05°) indicating that the MCPJ in this pony is a stable hinge joint with negligible extra-sagittal rotations. No substantial change in MCPJ maximum extension angles or vertical ground reaction forces (GRFv) were observed upon application of legwear during jump down exercise. Neoprene boot application yielded –65.20 ± 2.06° extension (GRFv = 11.97 ± 0.67 N/kg) and fleece polo wrap application yielded –64.23 ± 1.68° extension (GRFv = 11.36 ± 1.66 N/kg), when compared to naked control (-66.11 ± 0.96°; GRFv = 12.02 ± 0.53 N/kg). Collectively, this proof of concept study illustrates the benefits and practical limitations of using XROMM to document equine MCPJ kinematics in the presence and absence of legwear.

Supplementary Material to this article is available online at https://doi.org/10.3415/VCOT-16-06-0095.

Influence of support boots on fetlock joint angle of the forelimb of the horse at walk and trot

REASONS FOR PERFORMING STUDY

Support boots are thought to reduce tension on the superficial digital flexor tendon (SDTF) of the horse and are frequently recommended for horses convalescing after tendonitis, but evidence of their effectiveness is conflicting.

OBJECTIVE

To document the effects of 4 different types of support boots on fetlock joint angle in comparison to the unprotected fetlock.

METHODS

In 26 horses, the kinematics of the forelimb fetlock joint angle was measured at walk and trot on a treadmill when wearing 3 different types of support boots and 1 protective boot, as well as without boots. As outcome parameters, maximum extension of the fetlock joint and the moment at which maximum extension occurred in the stride cycle were determined.

RESULTS

At walk, 2 of the support boots reduced the maximum extension significantly by 0.8 and 0.9 degrees, respectively (P<0.05). Additionally, one type of boots also delayed the occurrence of maximal extension within the stride cycle. At trot, all support boots reduced maximum extension significantly by 0.56-1.44 degrees (P<0.01), and the protective boot reduced maximum extension by 0.56 degrees (P<0.05).

CONCLUSIONS AND POTENTIAL RELEVANCE

The results demonstrate the effectiveness of support boots in reducing maximum extension of the fetlock, which can be assumed to reduce tension in the suspensory apparatus and SDFT. The delay of the moment of maximal extension may be relevant in reducing dynamic forces. However, it should be noted that the long-term consequences of reduction of maximum fetlock extension are still uncertain. Such a reduction over a prolonged period might negatively affect fibre alignment in the healing tendon.

Effects of athletic taping of the fetlock on distal limb mechanics

REASONS FOR PERFORMING STUDY

Athletic taping is used frequently by human athletes to stabilise, maintain or strengthen soft tissue structures, but empirical evidence supporting any changes in equine kinematics is lacking.

OBJECTIVES

To assess the effects of athletic taping of the fetlock applied by an experienced athletic trainer on forelimb mechanics in healthy horses.

HYPOTHESES

That athletic taping of the distal forelimb reduces 1) hyperextension of the fetlock joint during stance, 2) flexion of the fetlock joint during swing and 3) ground reaction forces during stance.

METHODS

Ground reaction force and kinematic data were obtained for 6 healthy horses trotting at 3 m/sec for 4 sequential conditions (baseline, untaped; pre-exercise, taped; post exercise, taped post 30 mins trotting exercise; transfer, 4 h after tape removal). Data were analysed using 2-way mixed ANOVAs (condition; joint).

RESULTS

A statistically significant interaction was identified for the fetlock during the swing phase (mean +/- s.d. peak flexion at baseline 157 +/- 4 degrees, reduced with taping to 172 +/- 4 degrees; P<0.05) compared with no differences across conditions for the other joints. Peak vertical force reduced significantly (P<0.05) with taping.

CONCLUSIONS

Athletic taping of the fetlock does not alter the kinematics of the forelimb during stance, but does limit flexion of the fetlock during the swing phase. The decreased peak vertical force may be due to an increased proprioceptive effect.

POTENTIAL RELEVANCE

Reduced peak vertical forces may be of benefit in preventing or reducing injury. Further investigation remains necessary before it can be concluded that taping should be applied for tendinous or ligamentous rehabilitation in equine patients.