Joanne Kramer

Assessment of repeatability of a wireless, inertial sensor–based lameness evaluation system for horses

OBJECTIVE To determine repeatability of a wireless, inertial sensor-based lameness evaluation system in horses. ANIMALS 236 horses. PROCEDURES Horses were from 2 to 29 years of age and of various breeds and lameness disposition. All horses were instrumented with a wireless, inertial sensor-based motion analysis system on the head (accelerometer), pelvis (midline croup region [accelerometer]), and right forelimb (gyroscope) before evaluation in 2 consecutive trials, approximately 5 minutes apart, as the horse was trotted in a straight line. Signal-processing algorithms generated overall trial asymmetry measures for vertical head and pelvic movement and stride-by-stride differences in head and pelvic maximum and minimum positions between right and left sides of each stride. Repeatability was determined, and trial difference was determined for groups of horses with various numbers of strides for which data were collected per trial. RESULTS Inertial sensor-based measures of torso movement asymmetry were repeatable. Repeatability for measures of torso asymmetry for determination of hind limb lameness was slightly greater than that for forelimb lameness. Collecting large numbers of strides degraded stride-to-stride repeatability but did not degrade intertrial repeatability. CONCLUSIONS AND CLINICAL RELEVANCE The inertial sensor system used to measure asymmetry of head and pelvic movement as an aid in the detection and evaluation of lameness in horses trotting in a straight line was sufficiently repeatable to investigate for clinical use.

Comparison of an inertial sensor system with a stationary force plate for evaluation of horses with bilateral forelimb lameness

OBJECTIVE To assess the analytic sensitivity of an inertial sensor system for detection of the more severely affected forelimb in horses with bilateral lameness. ANIMALS 18 adult horses with forelimb lameness. PROCEDURES Horses were fitted with inertial sensors and evaluated for lameness with a stationary force plate as they were trotted in a straight line. Inertial sensor-derived measurements for vertical head movement asymmetry (HMA) and vector sum (VS) of maximum and minimum head height differences between right and left halves of the stride were used to predict differences in mean peak vertical force (PVF) as a percentage of body weight between the right and left forelimbs. Repeatability was compared by calculation of the intraclass correlation coefficient (ICC) for each variable. Correct classification percentages for the lamer forelimb were determined by use of a stationary force plate as the standard. RESULTS SEs of the prediction of difference in PVF between the right and left forelimbs from HMA and VS were 6.1% and 5.2%, respectively. Head movement asymmetry (ICC, 0.72) was less repeatable than PVF (ICC, 0.86) and VS (ICC, 0.84). Associations were positive and significant between HMA (R(2) = 0.73) and VS (R(2) = 0.81) and the difference in PVF between the right and left forelimbs. Correct classification percentages for HMA and VS for detecting the lamer forelimb were 83.3% and 77.8%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that an inertial sensor system to measure vertical asymmetry (HMA and VS) due to forelimb lameness in horses trotting in a straight line has adequate analytic sensitivity for clinical use. Additional studies are required to assess specificity of the system.

Comparison of an inertial sensor system of lameness quantification with subjective lameness evaluation

REASONS FOR PERFORMING STUDY Subjective evaluation of mild lameness has been shown to have poor interobserver reliability. Traditional methods of objective lameness evaluation require specialised conditions and equipment. Wireless inertial sensor systems have been developed to allow for simple, rapid, objective lameness detection in horses trotted over ground. OBJECTIVE The purpose of this study was to compare the sensitivities of an inertial sensor system and subjective evaluation performed by experienced equine practitioners at detecting lameness in horses. We hypothesised that the inertial sensor system would identify lameness at a lower level of sole pressure than a consensus of 3 experienced equine veterinarians. METHODS Fifteen horses were fitted with special shoes that allowed for lameness induction via sole pressure. Horses were simultaneously evaluated by 3 equine veterinarians and a wireless inertial sensor system. Horses were subjected to multiple trials: 1) before inserting the screw; 2) after inserting the screw to just touch the sole; and 3) after tightening the screw in half turn increments. The number of screw turns required for lameness identification in the correct limb by the inertial sensors and by consensus of 3 equine veterinarians was compared using the Wilcoxon test. RESULTS The inertial sensor system selected the limb with the induced lameness after fewer screw turns than did the 3 veterinarians (P<0.0001). The inertial sensor system selected the correct limb before the 3 veterinarians in 35 trials (58.33%), the evaluators selected the correct limb before the inertial sensors in 5 trials (8.33%), and in 20 trials (33.33%) they selected the correct limb at the same time. POTENTIAL RELEVANCE The inertial sensor system was able to identify lameness at a lower level of sole pressure than the consensus of 3 equine veterinarians. The inertial sensor system may be an effective aid to lameness localisation in clinical cases.

Effectiveness of administration of phenylbutazone alone or concurrent administration of phenylbutazone and flunixin meglumine to alleviate lameness in horses

OBJECTIVE To determine the effectiveness of administering multiple doses of phenylbutazone alone or a combination of phenylbutazone and flunixin meglumine to alleviate lameness in horses. ANIMALS 29 adult horses with naturally occurring forelimb and hind limb lameness. PROCEDURES Lameness evaluations were performed by use of kinematic evaluation while horses were trotting on a treadmill. Lameness evaluations were performed before and 12 hours after administration of 2 nonsteroidal anti-inflammatory drug (NSAID) treatment regimens. Phenylbutazone paste was administered at approximately 2.2 mg/kg, PO, every 12 hours for 5 days, or phenylbutazone paste was administered at approximately 2.2 mg/kg, PO, every 12 hours for 5 days in combination with flunixin meglumine administered at 1.1 mg/kg, IV, every 12 hours for 5 days. RESULTS Alleviation of lameness was greater after administration of the combination of NSAIDs than after oral administration of phenylbutazone alone. Improvement in horses after a combination of NSAIDs did not completely mask lameness. Five horses did not improve after either NSAID treatment regimen. All posttreatment plasma concentrations of NSAIDs were less than those currently allowed by the United States Equestrian Federation Inc for a single NSAID. One horse administered the combination NSAID regimen died of acute necrotizing colitis during the study. CONCLUSIONS AND CLINICAL RELEVANCE Administration of a combination of NSAIDs at the dosages and intervals used in the study reported here alleviated the lameness condition more effectively than did oral administration of phenylbutazone alone. This may attract use of combinations of NSAIDs to increase performance despite potential toxic adverse effects.

Effects of intra-articular botulinum toxin type A in an equine model of acute synovitis: a pilot study.

DePuy T, Howard R, Keegan K, Wilson D, Kramer J, Cook JL, Childers MK: Effects of intra-articular botulinum toxin type A in an equine model of acute synovitis: a pilot study. Am J Phys Med Rehabil 2007;86:777–783. Objective:To test the hypothesis that botulinum toxin type A (BoNT-A) can attenuate lameness associated with acute synovitis in an equine model. Design:Four horses 2–6 yrs of age with clinically normal carpi were studied for 15 days. Kinematic gait analysis and clinical measures of lameness were conducted before and after experimental interventions. Horses were randomly assigned to either placebo (saline) or treatment (BoNT-A) groups. On day 0 of the intervention, 50 units of BoNT-A or an equivalent volume of saline (0.09%) was given into the middle carpal joints. On day 14, acute synovitis was induced with intra-articular injection of recombinant equine interleukin-1 beta (IL-1&bgr;) 100 ng. Synovial fluid, clinical evaluation of lameness, and kinematic gait analysis were evaluated on day 15. Results:Synovitis was observed on histology and cytology in all horses after IL-1&bgr;, indicating acute suppurative inflammation. In the BoNT-A group, one horse developed lameness, whereas the other demonstrated no change in baseline gait evaluation. No adverse effects were observed in joints injected with BoNT-A or with saline alone. Conclusions:Our findings support the idea that BoNT-A can attenuate lameness in an equine model of acute synovitis. Our findings further suggest that BoNT-A might be a potential new treatment for painful arthritis; this warrants further study.

Detection of spinal ataxia in horses using fuzzy clustering of body position uncertainty

REASONS FOR PERFORMING STUDY Subjective neurological evaluation in horses is prone to bias. An objective method of spinal ataxia detection is not subject to these limitations and could be of use in equine practice and research. HYPOTHESIS Kinematic data in the walking horse can differentiate normal and spinal ataxic horses. METHODS Twelve normal and 12 spinal ataxic horses were evaluated by kinematic analysis walking on a treadmill. Each body position signal was reduced to a scalar measure of uncertainty then fuzzy clustered into normal or ataxic groups. Correct classification percentage (CCP) was then calculated using membership values of each horse in the 2 groups. Subsequently, a guided search for measure combinations with high CCP was performed. RESULTS Eight measures of body position resulted in CCP > or = 70%. Several combinations of 4-5 measures resulted in 100% CCP. All combinations with 100% CCP could be obtained with one body marker on the back measuring vertical and horizontal movement and one body marker each on the right fore- and hindlimb measuring vertical movement. CONCLUSIONS AND POTENTIAL RELEVANCE Kinematic gait analysis using simple body marker combinations can be used objectively to detect spinal ataxia in horses.

An attempt to detect lameness in galloping horses by use of body-mounted inertial sensors

OBJECTIVE To evaluate head, pelvic, and limb movement to detect lameness in galloping horses. ANIMALS 12 Thoroughbreds. PROCEDURES Movement data were collected with inertial sensors mounted on the head, pelvis, and limbs of horses trotting and galloping in a straight line before and after induction of forelimb and hind limb lameness by use of sole pressure. Successful induction of lameness was determined by measurement of asymmetric vertical head and pelvic movement during trotting. Differences in gallop strides before and after induction of lameness were evaluated with paired-sample statistical analysis and neural network training and testing. Variables included maximum, minimum, range, and time indices of vertical head and pelvic acceleration, head rotation in the sagittal plane, pelvic rotation in the frontal plane, limb contact intervals, stride durations, and limb lead preference. Difference between median standardized gallop strides for each limb lead before and after induction of lameness was calculated as the sum of squared differences at each time index and assessed with a 2-way ANOVA. RESULTS Head and pelvic acceleration and rotation, limb timing, stride duration measurements, and limb lead preference during galloping were not significantly different before and after induction of lameness in the forelimb or hind limb. Differences between limb leads before induction of lameness were similar to or greater than differences within limb leads before and after lameness induction. CONCLUSIONS AND CLINICAL RELEVANCE Galloping horses maintained asymmetry of head, pelvic, and limb motion between limb leads that was unrelated to lameness.

An in vitro biomechanical comparison of dynamic condylar screw plate combined with a dorsal plate and double plate fixation of distal diaphyseal radial osteotomies in adult horses.

OBJECTIVE To compare stiffness and strength of a dynamic condylar screw plate combined with dorsal broad dynamic compression plate (DCS-bDCP) fixation with double broad dynamic compression plate (dbDCP) fixation used to repair oblique distal fractures of adult equine radii. STUDY DESIGN Experimental. SAMPLE POPULATION Adult equine radii (n=10 pair). METHODS An unconstrained three-dimensional loading-measurement system was used to determine stiffness of a 50 mm long intact, and then DCS-bDCP or dbDCP-plated osteotomized/ostectomized segment of radii when subjected to a nondestructive sequence of compression, torsion, and lateral-to-medial (LM), medial-to-lateral (ML), cranial-to-caudal (CrCa), and caudal-to-cranial (CaCr) bending. Uniform load over the entire length of construct identified its weakest characteristics during torsion and LM and CrCa bending to failure. RESULTS No difference was observed between osteotomized/ostectomized DCS-bDCP and dbDCP construct stiffness for all 6 loading modes, and strength for all 3 failure loads. Ostectomized DCS-bDCP and dbDCP construct stiffness was significantly lower than osteotomized radii, the latter approaching intact for axial, LM, and CrCa bending. Most frequent failure was bone fracture through exit site of a screw located adjacent to osteotomy/ostectomy. CONCLUSIONS DCS-DCP and dbDCP constructs had comparable strength and stiffness when repairing osteotomies/ostectomies in equine adult radius bone. Fracture reduction increased stiffness that approached intact bone for loads that placed the unplated side in compression. CLINICAL RELEVANCE DCS-bDCP and dbDCP constructs are comparable in stiffness and strength when applied to oblique distal diaphyseal osteotomies/ostectomies in equine radius bone. However, the DCSs localized effect on distal epiphyseal structure because of additional bone removal remains to be investigated under in vivo articular loading conditions.