Shannon K. Reed

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.

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.

Associations of force plate and body-mounted inertial sensor measurements for identification of hind limb lameness in horses.

OBJECTIVE To investigate associations between inertial sensor and stationary force plate measurements of hind limb lameness in horses. ANIMALS 21 adult horses with no lameness or with mild hind limb lameness. PROCEDURES Horses were instrumented with inertial sensors and evaluated for lameness with a stationary force plate while trotting in a straight line. Inertial sensor-derived measurements of maximum and minimum pelvic height differences between right and left halves of the stride were compared with vertical and horizontal ground reaction forces (GRFs). Stepwise linear regression was performed to investigate the strength of association between inertial sensor measurements of hind limb lameness and amplitude, impulse, and time indices of important events in the vertical and horizontal GRF patterns. RESULTS Difference in minimum pelvic position was moderately (Ra(2) = 0.60) associated with the difference in peak vertical GRF but had little association with any horizontal GRF measurements. Difference in maximum pelvic position was strongly (Ra(2) = 0.77) associated with a transfer of vertical to horizontal ground reaction impulse in the second half of the stance but was not associated with difference in peak vertical GRF. CONCLUSIONS AND CLINICAL RELEVANCE Inertial sensor-derived measurements of asymmetric pelvic fall (difference in minimum pelvic position) indicated a decrease in vertical GRF, but similar measurements of asymmetric pelvis rise (difference in maximum pelvic position) indicated a transfer of vertical to horizontal force impulse in the second half of the stance. Evaluation of both pelvic rise and fall may be important when assessing hind limb lameness in horses.

Complications after orthopedic surgery in alpacas and llamas: 24 cases (2000-2006).

Objective— To report complications associated with orthopedic surgery in alpacas and llamas. Study Design— Retrospective study. Animals— Alpacas (n=18) and llamas (n=6) that orthopedic surgery using internal or external fixation. Methods— Medical records (January 2000–December 2006) and radiographs were reviewed and owners contacted for follow-up information for alpacas and llamas that had orthopedic surgery involving internal or external fixation. Fourteen camelids had internal fixation, 7 had external fixation, and 3 had a combination of internal and external fixation. Results— Twenty-two animals (92%) were discharged after surgery (mean hospitalization, 15 days). Of 20 animals with ≥1 year follow-up information, 18 were alive (82%). Postoperative complications related to fracture healing, infection, soft tissue structures, or joints occurred in 21 camelids (87%). Thirteen animals returned to their intended use, 4 animals returned to breeding but not their intended use, 4 were euthanatized, and 3 were only able to be used as pets. Conclusions— Fixation type (internal, external) did not have any significant effect on complications involving fracture healing, infection, soft tissue structures, or chronic lameness. Camelids with open fractures were more likely to have complications associated with fracture healing, repair, and infection than closed fractures. Clinical Relevance— Complications after orthopedic surgery in alpacas and llamas are more common than previously reported and may result in chronic lameness or prevent return to their intended use.OBJECTIVE To report complications associated with orthopedic surgery in alpacas and llamas. STUDY DESIGN Retrospective study. ANIMALS Alpacas (n=18) and llamas (n=6) that orthopedic surgery using internal or external fixation. METHODS Medical records (January 2000-December 2006) and radiographs were reviewed and owners contacted for follow-up information for alpacas and llamas that had orthopedic surgery involving internal or external fixation. Fourteen camelids had internal fixation, 7 had external fixation, and 3 had a combination of internal and external fixation. RESULTS Twenty-two animals (92%) were discharged after surgery (mean hospitalization, 15 days). Of 20 animals with >or=1 year follow-up information, 18 were alive (82%). Postoperative complications related to fracture healing, infection, soft tissue structures, or joints occurred in 21 camelids (87%). Thirteen animals returned to their intended use, 4 animals returned to breeding but not their intended use, 4 were euthanatized, and 3 were only able to be used as pets. CONCLUSIONS Fixation type (internal, external) did not have any significant effect on complications involving fracture healing, infection, soft tissue structures, or chronic lameness. Camelids with open fractures were more likely to have complications associated with fracture healing, repair, and infection than closed fractures. CLINICAL RELEVANCE Complications after orthopedic surgery in alpacas and llamas are more common than previously reported and may result in chronic lameness or prevent return to their intended use.

The suspensory apparatus and digital flexor muscles of the llama (Lama glama) 2: The pelvic limb

Fueron disecados e ilustrados los musculos flexores digitales del miembro toracico de cuatro llamas con la finalidad de aportar datos sobre el aparato suspensor (de apoyo) que soportan estas estructuras. Se realizo una extensa busqueda bibliografica dada la incompleta informacion existente de estas estructuras anatomicas. La popularidad de la llama en todo el mundo como uno de los animales domesticos utilizados ha aumentado en los ultimos anos. Es importante describir detalladamente la anatomia de esta especie para su tratamiento en condiciones patologicas. La descripcion de las estructuras anatomicas y las ilustraciones originales demuestran peculariedades genuinas y diferencias entre la llama y los rumiantes domesticos. En llamas, las tres cabezas del musculo flexor profundo de los dedos se originan y se conectan entre ellas en una muy peculiar combinacion, con uno de los tendones recibiendo un fasciculo del musculo flexor ulnar del carpo. El musculo flexor superficial de los dedos tiene un tendon delgado el cual se fusiona con la fascia palmar y luego se amplia. No existen musculos interflexores. Adicionalmente, fueron encontrados musculos lumbricales en la extremidad distal y variaban en numero entre los miembros. Finalmente, en este trabajo se evalua el aparato suspensorio del miembro toracico.

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.

Molecular and histologic evaluation of idiopathic hyperextension of the metacarpophalangeal and metatarsophalangeal joints in adult llamas

OBJECTIVE To determine the molecular and histologic characteristics of hyperextension of the metacarpophalangeal and metatarsophalangeal joints in adult llamas. ANIMALS 12 adult llamas (6 with bilateral hyperextension of the metacarpophalangeal or metatarsophalangeal joints [affected] and 6 age- and sex-matched clinically normal control llamas). PROCEDURES Llamas were euthanized, and specimens of superficial digital flexor tendon, deep digital flexor tendon, and suspensory ligament were obtained from 4 areas and snap frozen in liquid nitrogen or suspended in neutral-buffered 10% formalin. Histologic evaluation of collagen fiber orientation, elastin content, and proteoglycan content was performed by use of Masson trichrome, picrosirius red, Verhoeff, and Alcian blue stains. Total RNA was isolated from frozen suspensory ligament specimens. Gene expression of collagen types I and III, lysyl oxidase, and matrix metalloproteinase-13 was evaluated with a real-time quantitative reverse transcriptase PCR assay. RESULTS Gene expression of collagen types I and III, lysyl oxidase, and matrix metalloproteinase-13 in suspensory ligaments was similar between affected and control llamas. Collagen orientation and elastin content of the flexor tendons and suspensory ligaments were also similar between the groups. Proteoglycan content was low in most specimens but was focally increased in discrete lesions of suspensory ligaments in 2 affected and 2 control llamas. CONCLUSIONS AND CLINICAL RELEVANCE Hyperextension of the metacarpophalangeal or metatarsophalangeal joints in llamas did not appear to be caused by degeneration or inflammation of the suspensory ligament. Although focal proteoglycan accumulation existed in the suspensory ligaments of 2 affected llamas, widespread abnormal connective tissue proteoglycan accumulation was not found.

Evaluation of serum trace mineral, vitamin D, and sex steroid hormone concentration, and survey data in llamas and alpacas with metacarpophalangeal and metatarsophalangeal hyperextension

OBJECTIVE To characterize serum trace mineral, sex steroid hormone, and vitamin D concentrations and identify factors associated with metacarpophalangeal and metatarsophalangeal hyperextension in llamas and alpacas. SAMPLES Serum samples from 79 llamas and 15 alpacas and owner survey data for 573 llamas and 399 alpacas. PROCEDURES Serum samples were stored at -20°C until analysis and were evaluated for trace mineral, vitamin D, estradiol, progesterone, and testosterone concentrations. Information regarding age of onset, number of affected animals in herd, feed and supplements given, type of housing, and management practices was obtained in an owner survey. RESULTS Higher serum zinc and iron concentrations were associated with metacarpophalangeal and metatarsophalangeal hyperextension in camelids, compared with controls. In summer and fall months, vitamin D concentrations were significantly higher in affected camelids than controls. Overall prevalence was 13.3% in llamas, compared with 0.7% in alpacas. No management factors were found to be predictive of this condition. No other factors examined were associated with metacarpophalangeal and metatarsophalangeal hyperextension. CONCLUSIONS AND CLINICAL RELEVANCE Despite similar supplementation practices and environmental conditions between affected and unaffected animals, an association of high serum zinc, iron, and vitamin D concentrations in affected camelids, compared with controls, may indicate differences of intake or absorption of dietary supplements.

Molecular, histologic, and trace mineral characterization of metacarpophalangeal and metatarsophalangeal joint hyperextension in juvenile llamas.

OBJECTIVE To evaluate molecular and histologic characteristics of the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), and suspensory ligament (SL) and assess trace-mineral concentrations in serum, liver, and hair of juvenile llamas with metacarpophalangeal and metatarsophalangeal joint hyperextension. ANIMALS 12 juvenile llamas (6 with bilateral hyperextension of metacarpophalangeal joints, metatarsophalangeal joints, or both and 6 clinically normal control llamas). PROCEDURES Radiography and ultrasonography of metacarpophalangeal and metatarsophalangeal regions were performed. Llamas were euthanized, and SDFT, DDFT, and SL samples were collected for histologic evaluation of collagen and elastin content and orientation, proteoglycan content, and collagen type III immunohistochemistry. Total RNA was isolated from SL tissue, and gene expression of collagen types I and III, lysyl oxidase, and matrix metalloproteinase-13 was evaluated via real-time quantitative reverse transcriptase PCR assay. Liver, serum, and hair samples were evaluated for trace mineral content. RESULTS Collagen type III gene expression and proteoglycan content were significantly increased in SL samples of affected juvenile llamas, compared with those of control llamas. No difference was detected in collagen and elastin content and orientation or in gene expression of collagen type I, lysyl oxidase, or matrix metalloproteinase-13 between groups. Affected llamas had significantly increased serum molybdenum and decreased liver cobalt concentrations, compared with values for control llamas. CONCLUSIONS AND CLINICAL RELEVANCE Increased collagen type III gene expression and proteoglycan content in SL samples of affected juvenile llamas provided evidence of ongoing SL matrix repair. Trace mineral differences may have been attributable to dietary imbalances in affected llamas.