Characteristics of Hoof Landing in Sound Horses and the Influence of Trimming and Shoeing Examined With Hoof-Mounted Inertial Sensors.

The aim of the current in vivo, observational study was to investigate the effects of different hoof manipulations on landing duration (LandD), location (ICloc) and angle of initial contact (ICangle) in the front feet of horses. A novel, hoof-mounted, inertial measurement unit sensor system (IMU) was used. Ten sound, crossbred horses were fitted with an IMU sensor at the dorsal hoof wall and examined barefoot and after trimming. Additionally, the application of 120 g lateral weights and 5° medial side wedges as well as steel, aluminium, egg bar, and lateral extension shoes were tested. Horses were guided in a straight line on firm ground. The use of steel shoes increased LandD compared to barefoot and enhanced the individual ICloc in trot. Application of rolled toe shoes caused a longer LandD than use of plain shoes. None of the other modifications significantly influenced the timing or spatial variables of hoof landing. Trimming and shoeing have less impact on the landing pattern of horses than assumed in practice. Still, the use of steel shoes changes sliding properties of the hooves on firm ground and increases weight causing a longer LandD and reinforcement of the individual ICloc.

Bilateral Change in Vertical Hoof Force Distribution in Horses with Unilateral Forelimb Lameness before and after Successful Diagnostic Anaesthesia.

Kinetic examinations of horses with induced lameness as well as the effect of perineural anaesthesia in sound horses have shown promise, but clinical studies regarding the effect of diagnostic anaesthesia during the different stance phases are rare. Fourteen horses with unilateral forelimb lameness were examined with the Hoof™ System during trot to assess vertical force distribution (in kg) affecting both front hooves before and after diagnostic anaesthesia during landing, midstance, and breakover. For statistical analysis, a covariance analysis with repeated measurements regarding the limb (lame/sound) as well as anaesthesia (before/after) and the covariable body weight was performed. The p-values for the pairwise comparisons were adjusted using the Bonferroni−Holm correction (p < 0.05). For all phases of the stance, a significant interaction between the factors limb and anaesthesia was shown. Before diagnostic anaesthesia, vertical force was significantly reduced on the lame limb compared to the sound limb during landing (−25%, p < 0.001), midstance (−20%, p < 0.001) and breakover (−27%, p < 0.001). After anaesthesia, the difference between both forelimbs was not significant anymore for all phases. The vertical force on the lame limb increased significantly after positive anaesthesia during the whole stance phase, with breakover being most affected (+27%, p = 0.001). Pressure measurements with the Hoof™ System can be used to evaluate the effect of diagnostic anaesthesia in a clinical setting with pain-related vertical force asymmetries being neutralised after diagnostic anaesthesia. Breakover is the main event influenced by lameness.

Influence of trimming, hoof angle and shoeing on breakover duration in sound horses examined with hoof-mounted inertial sensors.

OBJECTIVE: Aim of the current in vivo, observational study was to investigate the effect of trimming, heel elevation and different types of shoeing on breakover duration (BreakD) with a novel, hoof-mounted inertial measurement unit (IMU) sensor system. METHODS: Ten sound, crossbred horses were examined barefoot before and after trimming fitted with an IMU sensor at the dorsal hoof wall. Additionally, application of 5° heel wedges, plain steel shoes, rolled-toe shoes and palmarly-placed quarter-clip shoes was tested. Horses were guided in a straight line on firm ground. Obtained data were speed corrected prior to calculations testing the influence of different manipulations for their significance on BreakD. RESULTS: Trimming had no significant influence on BreakD. Heel elevation caused a significant decrease of BreakD in walk and trot. Shoeing with a plain steel shoe resulted in a significant increase in BreakD in walk. This could be rescinded by creating a rolled toe or placing the shoe palmarly. CONCLUSION: Obtained results emphasize the use of heel wedges or rolled-toe and palmarly-placed shoes to ease breakover in the context of therapeutic shoeing. Hoof-mounted IMU sensors with high resolution seem to be a practical and valuable approach to accurately examine BreakD and factors influencing this parameter.

Effect of Perineural Anesthesia on the Centre of Pressure (COP) Path During Stance Phase at Trot in Sound Horses.

This study aimed to examine how short-term loss of proprioception in the equine foot influences the individual COP path during the stance phase of the trot in sound horses. Ten horses were evaluated to be objectively non-lame using the 'Equinosis Q System and subsequently examined using a portable pressure measuring system with pressure foils fixed directly underneath both front hooves prior to and after perineural anesthesia of the palmar digital nerves. The individual COP paths of both forelimbs was assessed prior to and after unilateral and bilateral abaxial sesamoid nerve blocks. COP from initial contact to mid stance and breakover as well as the inter-stride variability were descriptively evaluated for each horse and limb. The individual COP path for each horse and limb during stance was shown to be highly repeatable without significant inter-stride variability. Location of initial contact, COP during midstance and breakover are not affected by unilateral or bilateral short-term loss of sensory feedback from the foot after perineural anesthesia. Anesthesia of the foot with an abaxial sesamoid nerve block does not affect the foot's COP during stance at a trot, therefore, sudden changes in gait pattern after perineural anesthesia should be interpreted with caution and warrant further clinical investigation.

Detection of Equine Hoof Motion by Using a Hoof-Mounted Inertial Measurement Unit Sensor in Comparison to Examinations with an Optoelectronic Technique - A Pilot Study.

This study aimed to determine whether a hoof-mounted inertial measurement unit (IMU) system would provide similar timing characteristics and step lengths, in walk and trot on different grounds, compared to those of an established optoelectronic motion system. The right hoof of one horse was equipped with an IMU sensor with an optical reference marker on top. Fifteen steps on firm ground, and five on penetrable ground, were performed at walk and trot. Level of agreement between the two measurement systems was determined by assessing the concordance correlation coefficients, accuracy, and precision of the duration of different gait events and step length. Timing characteristics and step length were in strong agreement between the two techniques for the majority of assessed parameters in walk and trot on both grounds. The agreement between techniques decreased for breakover and landing duration at trot on penetrable ground. Disparity between the measurement techniques was related to difficulties in accurately defining single parts of the stance phase with marker-based optoelectronic analysis on penetrable ground. Detailed examinations of different parts of the stance phase are more accurately performed using hoof-mounted IMU sensors. Results emphasise the great potential of IMU sensors for equine motion analysis in daily practice.

Comparative anatomic and morphometric examination of the interosseous muscle, sesamoid ligaments and flexor tendons of the fetlock in South American camelids.

This study presents a comparative morphological and morphometrical examination of the interosseous muscle (IOM), digital flexor tendons and associated structures of all four species of South American Camelids (SACs): Lama (Lama glama), alpaca (Vicugna pacos), guanaco (Lama guanicoe) and vicuna (Vicugna vicugna). Our findings show that the lamoid interosseous muscle and digital flexor tendons are very similar between species and differences, which have been reported previously, are possibly due to diverging examiner interpretation. Lumbricalis muscles were mostly found as single muscles in this study. The definition of the terminal and dorsal branches of the interosseous muscle is critically revised. The analysis of morphometric data indicates that the size of the individual has a substantial influence on the cross-sectional area (CSA) of the examined structures. Metacarpal/metatarsal bone width is a main predictor of CSA, while the factor species only shows significance in specific sample points. For lama and alpaca, no differences in CSA in relation to species as factor were found. The IOM shows the largest CSAs of the three examined structures in all species, which implies an important load-bearing function. Considerable individual variation remains unexplained by the mentioned factors. This lowers the prospect of CSA reaching diagnostic importance in SAC fetlock pathology.

Correlations between the equine metacarpophalangeal joint angulation and toe conformation in statics.

The angulation of the equine fetlock determines the load of associated tendons and probably their predisposition for injuries. However, it is questionable how the individual toe conformation and tendon properties interact with the dorsal metacarpophalangeal joint angle (DMPJ). Data are needed for a tangible evaluation of the equine limb conformation for more specific orthopaedic treatment. The aim was to evaluate the correlation between the DMPJ, toe conformation and cross-sectional area (CSA) of both flexor tendons; the superficial digital flexor tendon (SDFT) and deep digital flexor tendon (DDFT). Thirty Warmblood horses were available for the study. Lateromedial radiographs of the toe and fetlock and transverse ultrasound images of both flexor tendons were obtained from three zones. The DMPJ, length and angle of the phalanges and CSA SDFT/DDFT were measured. In addition, hoof angle, wither height, age, and sex were documented. Correlations were calculated using Pearson's test. A paired t-test was used to evaluate left-right differences. Length and angle of the proximal and middle phalanx were significantly associated with the DMPJ (r = -0.28 - -0.45, p<0.001-0.04). Neither the angle of the hoof and distal phalanx nor the CSA SDFT/DDFT, showed a noticeable correlation with the DMPJ. Significant left-right differences occurred for the DMPJ (p<0.002) and the angle of the proximal and middle phalanx (p<0.01 - 0.002). A moderate negative correlation was shown between the DMPJ and wither height (r = - 0.31, p=0.04). Results represent only a specific population. The study provides only a static evaluation of a dynamic situation. In a clinical context, it might be useful to focus on the angulation and length of the pastern to evaluate the individual load affecting the DMPJ and its associated structures. These findings might be relevant for orthopaedic treatments and shoeing recommendations.

Immediate effects of an artificial change in hoof angulation on the dorsal metacarpophalangeal joint angle and cross-sectional areas of both flexor tendons.

Corrective shoeing is used to change hoof angulation with the intention to influence the angulation of the digital joints to reduce strain on associated tendons. The objective of this study is to examine how gradual changes in hoof angulation affect the dorsal metacarpophalangeal joint (DMPJ) angulation and cross-sectional areas (CSAs) of the deep digital flexor tendon (DDFT) and superficial digital flexor tendon (SDFT) concerning the individual toe conformation. Forelimbs of 30 horses were examined barefoot and equipped with 5°, 10° and 20° toe wedges (TWs) and heel wedges (HWs). Phalangeal angulation and lengths were measured in lateromedial radiographs of the digit. CSAs of both flexor tendons was calculated in sonographic images. Significant effects on the DMPJ and CSA of the DDFT/SDFT were measured with 10° and 20° HWs or 20° TWs. Both flexor tendons showed increasing CSA after heel elevation. Significant interindividual variations occurred. Phalangeal angulation and length influenced the responsivity of the parameters to a changed hoof angulation. Significant impact of corrective shoeing on the DMPJ and flexor tendons is related to a distinct change in hoof orientation and varies with individual toe conformation. Similar response of the DDFT and SDFT to raised and lowered hoof orientation needs further investigation for a more specific application of therapeutic shoeing.