Individual speed dependency of forelimb lameness in trotting horses

Using a system for motion analysis, linear correlation of speed and forelimb lameness was measured in 16 horses trotting on a treadmill at a minimum of three different trotting speeds. Forelimb lameness was determined as asymmetry of vertical head motion during left and right forelimb stance.In seven horses with a moderate forelimb lameness (head motion asymmetry >40%), lameness increased significantly with trotting speed. In a further seven horses with mild or subclinical forelimb lameness (head motion asymmetry <40%) and in two horses with a moderate forelimb lameness, no significant correlation between speed and motion asymmetry was found.The results indicate that moderate forelimb lameness measured as head motion asymmetry depends on the speed at which the measurements are taken. If head motion asymmetry is measured at two trotting speeds, it can be standardized to any speed within the trotting speed range.     

Computerized detection of supporting forelimb lameness in the horse using an artificial neural network.

The purpose of this study was to investigate whether artificial neural networks could be used to determine equine lameness by computational means only. The integral parts of our approach were the combination of automated signal tracking of horses on a treadmill and the computational power of artificial neural networks (ANN). The motion of 175 horses trotting on a treadmill was recorded using the SELSPOT II system for motion analysis. Two cameras traced infrared (IR) markers on the head and on the left forehoof. The motion of the head was Fourier-transformed and further processed by a multilayer feedforward ANN, which was trained to distinguish healthy from pathological gaits and to quantify the lameness. The classification was correct in 78.6% of cases. In 12% of cases the network gave contradictory results, in 5.9% the network found no answers, and in 3.5% the answers were wrong. However after proper training, it is proposed that neural networks are potentially capable of making a non-human diagnosis of equine lameness.     

Association between subjective lameness grade and kinetic gait parameters in horses with experimentally induced forelimb lameness

OBJECTIVE: To evaluate the association between subjective lameness grades and kinetic gait parameters and assess the variability in kinetic parameters in horses with experimentally induced forelimb lameness. ANIMALS: 32 horses. PROCEDURES: Forelimb lameness was induced in each horse via injection of lipopolysaccharide into 1 metacarpophalangeal joint (40 experimental trials). Subjective lameness grading and 13 kinetic gait parameters (force plate analysis) were assessed before (baseline) and at 12, 18, and 24 hours after lipopolysaccharide injection. While horses were trotting, kinetic gait analysis was performed for 8 valid repetitions at each time point. Repeated-measures analyses were performed with 8 repetitions for each kinetic parameter as the outcome, and lameness grades, time points after lipopolysaccharide injection, and repetition order as explanatory variables. Sensitivity and specificity of kinetic parameters for classification of horses as sound or lame (in relation to subjective lameness scores) were calculated. Between- and within-horse variabilities of the 13 kinetic parameters were assessed by calculation of coefficients of variation. RESULTS: Subjective lameness grades were significantly associated with most of the kinetic parameters. Vertical force peak and impulse had the lowest between- and within-horse coefficients of variation and the highest correlations with subjective lameness grade. Vertical force peak had the highest sensitivity and specificity for lameness classification. Vertical force peak and impulse were significantly decreased even in horses with mild or unobservable lameness. CONCLUSIONS AND CLINICAL RELEVANCE: Among the kinetic gait parameters, vertical force peak and impulse had the best potential to reflect lameness severity and identify subclinical forelimb gait abnormalities.     

Force platform evaluation of lameness severity following extracorporeal shock wave therapy in horses with unilateral forelimb lameness

OBJECTIVE: To measure alterations in lameness severity that occur following use of extracorporeal shock wave therapy (ESWT) in horses with naturally occurring unilateral forelimb lameness. DESIGN: Nonrandomized clinical trial. ANIMALS: 9 horses with unilateral forelimb lameness. PROCEDURES: Force platform gait analysis was performed prior to administration of any treatments (baseline) and after use of local anesthesia to eliminate the lameness. Extracorporeal shock wave therapy was then administered, and gait analysis was repeated 8 hours later and then daily for 7 days. RESULTS: Compared with the baseline value, peak vertical force was significantly increased 8 hours and 2 days after ESWT, and peak vertical force on day 2 was not significantly different from force measured after use of local anesthesia to eliminate the lameness. Similarly, vertical impulse was significantly increased, compared with the baseline value, 8 hours and 2 days after ESWT, but at all times, it was significantly lower than vertical impulse measured after use of local anesthesia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in horses with naturally occurring lameness, use of ESWT results in a period of acute improvement in lameness severity that typically persists for 2 days. Thus, in horses undergoing ESWT, exercise should be controlled for a minimum of 2 days after treatment to prevent further injury.     

Supporting forelimb lameness: clinical judgement vs. computerised symmetry measurement.

The aim of this study was to compare supporting forelimb lameness determined by a motion analysis system with the subjective grading of a trained equine orthopaedic surgeon. Trotting on a treadmill, 29 individuals with a supporting forelimb lameness were measured with the SELSPOT II system and judged by the clinician. The vertical motion of the head was measured, analysed using Fourier transform, and the percentages of symmetry determined. The veterinarian evaluated the lameness and graded it according to a clinical routine. Veterinarian and system for motion analysis assigned the lameness to the same leg in all cases, but the grading of the lameness differed in 6 out of 29 cases. The results of this study indicate that motion analysis can be used as an informative tool supporting the subjective veterinary judgement.     

The effect of induced forelimb lameness on thoracolumbar kinematics during treadmill locomotion

REASONS FOR PERFORMING STUDY: Lameness has often been suggested to result in altered movement of the back, but there are no detailed studies describing such a relationship in quantitative terms. OBJECTIVES: To quantify the effect of induced subtle forelimb lameness on thoracolumbar kinematics in the horse. METHODS: Kinematics of 6 riding horses was measured at walk and at trot on a treadmill before and after the induction of reversible forelimb lameness grade 2 (AAEP scale 1-5). Ground reaction forces (GRF) for individual limbs were calculated from kinematics. RESULTS: The horses significantly unloaded the painful limb by 11.5% at trot, while unloading at walk was not significant. The overall flexion-extension range of back motion decreased on average by 0.2 degrees at walk and increased by 3.3 degrees at trot (P<0.05). Changes in angular motion patterns of vertebral joints were noted only at trot, with an increase in flexion of 0.9 degrees at T10 (i.e. angle between T6, T10 and T13) during the stance phase of the sound diagonal and an increase in extension of the thoracolumbar area during stance of the lame diagonal (0.7degrees at T13, 0.8 degres at T17, 0.5 degres at L1, 0.4 degrees at L3 and 0.3 degrees at L5) (P<0.05). Lameness further caused a lateral bending of the cranial thoracic vertebral column towards the lame side (1.3 degrees at T10 and 0.9 degrees at T13) (P<0.05) during stance of the lame diagonal. CONCLUSIONS: Both range of motion and vertebral angular motion patterns are affected by subtle forelimb lameness. At walk, the effect is minimal, at trot the horses increased the vertebral range of motion and changed the pattern of thoracolumbar motion in the sagittal and horizontal planes, presumably in an attempt to move the centre of gravity away from the lame side and reduce the force on the affected limb. POTENTIAL RELEVANCE: Subtle forelimb lameness affects thoracolumbar kinematics. Future studies should aim at elucidating whether the altered movement patterns lead to back and/or neck dysfunction in the case of chronic lameness.     

A case of sesamoid bone fragmentation in the leg as the cause of lameness in a female Rottweiler

An eight-month-old female rottweiler was presented with a history of intermittent lameness of the right hindlimb of 4 weeks duration. Radiographs showed a fragmentation in two plantar sesamoid bones of the metatarsophalangeal joint. Based on these clinical and radiographic signs sesamoid disease of the 2nd and 7th sesamoid bone in the right hindpaw was diagnosed. The fragmented sesamoids were surgically removed and histologically examined. The treatment was successful and the dog became lamnessfree. Additional radiographs showed fragmentations of sesamoid bones VII of both the forepaws, but they did not cause any lameness.     

Changes in kinematic variables observed during pressure-induced forelimb lameness in adult horses trotting on a treadmill

OBJECTIVE: To determine whether kinematic changes induced by heel pressure in horses differ from those induced by toe pressure. ANIMALS: 10 adult Quarter Horses. PROCEDURE: A shoe that applied pressure on the cuneus ungulae (frog) or on the toe was used. Kinematic analyses were performed before and after 2 levels of frog pressure and after 1 level of toe pressure. Values for stride displacement and time and joint angles were determined from horses trotting on a treadmill. RESULTS: The first level of frog pressure caused decreases in metacarpophalangeal (fetlock) joint extension during stance and increases in head vertical movement and asymmetry. The second level of frog pressure caused these changes but also caused decreases in stride duration and carpal joint extension during stance as well as increases in relative stance duration. Toe pressure caused changes in these same variables but also caused maximum extension of the fetlock joint to occur before midstance, maximum hoof height to be closer to midswing, and forelimb protraction to increase. CONCLUSION AND CLINICAL RELEVANCE: Decreased fetlock joint extension during stance and increased head vertical movement and asymmetry are sensitive indicators of forelimb lameness. Decreased stride duration, increased relative stance duration, and decreased carpal joint extension during stance are general but insensitive indicators of forelimb lameness. Increased forelimb protraction, hoof flight pattern with maximum hoof height near midswing, and maximum fetlock joint extension in cranial stance may be specific indicators of lameness in the toe region. Observation of forelimb movement may enable clinicians to differentiate lameness of the heel from lameness of the toe.     

Adenocarcinoma metastasis of the intertransversarius cervicis muscle eliciting a right forelimb lameness in a dog

This article describes identification of a metastatic adenocarcinoma to the intertransversarius cervicis muscle using magnetic resonance imaging (MRI) in a dog that presented with chronic lameness of the right forelimb. Magnetic resonance imaging revealed a right sided, ovoid signal abnormality within the intertransversarius cervicis muscle lateral to the sixth cervical (C6) vertebra. The lesion was uniform, hyperintense on T2- and isointense on T1-weighted images to muscle and exhibited uniform contrast enhancement on T1-weighted images. The MRI findings were consistent with a neoplasia. Surgical excision was performed. Histopathological diagnosis was metastatic fibrous adenocarcinoma. The dog recovered rapidly but 6 months post-operatively he was killed because of lung metastases. Necropsy was declined and the primary tumour could not be identified.     

Subclinical fungal endometritis in an 8-year-old Hanoverian mare

Clinical and subclinical endometritis are leading causes of reduced reproductive efficiency in the mare. Clinical endometritis is relatively easy to diagnose during routine physical and ultrasonographic reproductive examinations, whereas the diagnosis of subclinical endometritis requires a more detailed work-up. The goal of this paper is to review the various options, and describe the regimen chosen in a mare with subclinical fungal endometritis.     

Compensatory load redistribution of horses with induced weight-bearing forelimb lameness trotting on a treadmill

The study was performed to obtain a detailed insight into the load and time shifting mechanisms of horses with unilateral weight-bearing forelimb lameness. Reversible lameness was induced in 11 clinically sound horses by applying a solar pressure model. Three degrees of lameness (subtle, mild and moderate) were induced and compared with sound control measurements. Vertical ground reaction force-time histories of all four limbs were recorded simultaneously on an instrumented treadmill. Four compensatory mechanisms could be identified that served to reduce structural stress, i.e. peak vertical force on the affected limb: (1) with increasing lameness, horses reduced the total vertical impulse per stride; (2) the diagonal impulse decreased selectively in the lame diagonal; (3) the impulse was shifted within the lame diagonal to the hindlimb and in the sound diagonal to the forelimb; (4) the rate of loading and the peak forces were reduced by prolonging the stance duration. Except in the diagonal hindlimb, where peak vertical forces increased slightly in the moderate lameness condition, no equivalent compensatory overload situation was observed in the other limbs. Specific force and time information of all four limbs allow the unequivocal identification of the affected limb.     

The use of computed tomography to diagnose bilateral forelimb tendon pathology in a horse with unilateral lameness

A horse with unilateral forefoot lameness had bilateral deep digital flexor tendon (DDFT) lesions on computed tomography (CT). Venous contrast enhanced CT revealed distal sesamoidean impar desmitis in the lame forelimb. Computed tomography is useful for diagnosis of soft tissue lesions within the hoof capsule and contrast enhancement improves lesion conspicuity.