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- Author or Editor: Henk Schamhardt x
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Abstract
Objective—To calculate forces in the flexor tendons and the influence of heel wedges in affected and contralateral (compensating) forelimbs of horses with experimentally induced unilateral tendinitis of the superficial digital flexor (SDF) tendon.
Animals—5 Warmblood horses.
Procedure—Ground reaction force and kinematic data were obtained during a previous study while horses were trotting before and after induction of tendinitis in 1 forelimb SDF and after application of 6° heel wedges to both forehooves. Forces in the SDF, deep digital flexor (DDF), and the suspensory ligament (SL) and strain in the accessory ligament (AL) of the DDF were calculated, using an in vitro model of the distal region of the forelimb.
Results—After induction of tendinitis, trotting speed slowed, and forces decreased in most tendons. In the affected limb, SL force decreased more than SDF and DDF forces. In the compensating limb, SDF force increased, and the other forces decreased. After application of heel wedges, SDF force in both limbs increased but not significantly. Furthermore, there was a decrease in DDF force and AL strain.
Conclusions and Clinical Relevance—The increase in SDF force in the compensating forelimb of horses with unilateral SDF tendinitis may explain the high secondary injury rate in this tendon. The lack of decrease of SDF force in either limb after application of heel wedges suggests that heel wedges are not beneficial in horses with SDF tendinitis. Instead, heel wedges may exacerbate the existing lesion. (Am J Vet Res 2002;63:432–437)
Abstract
Objective—To describe a method to calculate flexor tendon forces on the basis of inverse dynamic analysis and an in vitro model of the equine forelimb and to quantify parameters for the model.
Sample Population—38 forelimbs of 23 horses that each had an estimated body mass of ≥ 500 kg.
Procedure—Longitudinal limb sections were used to determine the lines of action of the tendons. Additionally, limb and tendon loading experiments were performed to determine mechanical properties of the flexor tendons.
Results—The study quantified the parameters for a pulley model to describe the lines of action. Furthermore, relationships between force and strain of the flexor tendons and between fetlock joint angle and suspensory ligament strain were determined, and the ultimate strength of the tendons was measured.
Conclusion and Clinical Relevance—The model enables noninvasive determination of forces in the suspensory ligament, superficial digital flexor tendon, and distal part of the deep digital flexor (DDF) tendon. In addition, it provides a noninvasive measure of loading of the accessory ligament of the DDF tendon for within-subject comparisons. However, before application, the method should be validated. The model could become an important tool for use in research of the cause, prevention, and treatment of tendon injuries in horses. (Am J Vet Res 2001;62:1585–1593)
Abstract
Objective—To determine the validity of using skin-fixated markers to assess kinematics of the thoracolumbar vertebral column in horses.
Animals—5 Dutch Warmblood horses without abnormalities of the vertebral column.
Procedure—Kinematics of T6, T10, T13, T17, L1, L3, L5, S3, and both tuber coxae were determined by use of bone-fixated and skin-fixated markers. Threedimensional coordinate data were collected while horses were walking and trotting on a treadmill. Angular motion patterns were calculated and compared on the basis of 2-dimensional analysis of data from skin-fixated markers and 3-dimensional analysis of data from bone-fixated markers.
Results—Flexion-extension of thoracolumbar vertebrae and axial rotation of the sacrum were satisfactorily determined at both the walk and trot, using skinfixated markers. Data from skin-fixated markers were accurate for determining lateral bending at the walk in the midthoracic and lower lumbar portion of the vertebral column only. However, at the trot, data from skin-fixated markers were valid for determining lateral bending for all thoracolumbar vertebrae.
Conclusions and Clinical Relevance—Caution should be taken when interpreting data obtained by use of skin-fixated markers on lateral bending motions during the walk in horses. For determination of other rotations at the walk and all rotations at the trot, use of skin-fixated markers allows valid calculations of kinematics of the vertebral column. Understanding to what extent movements of skin-fixated markers reflect true vertebral motion is a compulsory step in developing noninvasive methods for diagnosing abnormalities of the vertebral column and related musculature in horses. (Am J Vet Res 2001;62:301–306)
Abstract
Objective—To determine movements of the vertebral column of horses during normal locomotion.
Animals—5 young Dutch Warmblood horses that did not have signs of back problems or lameness.
Procedure—Kinematics of 8 vertebrae (T6, T10, T13, T17, L1, L3, L5, and S3) and both tuber coxae were determined, using bone-fixated markers. Measurements were recorded when the horses were trotting on a treadmill at a constant speed of 4.0 m/s.
Results—Flexion-extension and axial rotation were characterized by a double sinusoidal pattern of motion during 1 stride cycle, whereas lateral bending was characterized by 1 peak and 1 trough. Ranges of motion for all vertebrae were: flexion-extension, 2.8o to 4.9o; lateral bending, 1.9° to 3.6°; axial rotation, 4.6° to 5.8°, except for T10 and T13, where the amount of axial rotation decreased to 3.1° and 3.3°, respectively.
Conclusion and Clinical Relevance—During locomotion, 3 types of rotations are evident in the thoracolumbar vertebrae. Regional differences are observed in the shape and timing of the rotations. These differences are related to actions of the limbs. The method described here for direct measurement of vertebral column motion provides insights into the complex movements of the thoracolumbar portion of the vertebral column in trotting horses. Information on normal kinematics is a prerequisite for a better understanding of abnormal function of the vertebral column in horses. (Am J Vet Res 2001;62:757–764)
Abstract
Objective—To measure and correlate kinematic and ground reaction force (GRF) data in horses with superficial digital flexor tendinitis.
Animals—6 sound horses.
Procedure—Horses were evaluated before (sound evaluation) and after (lame evaluation) induction of superficial digital flexor tendinitis in 1 forelimb (randomized) by injection of collagenase. As each horse trotted, kinematic data were collected by use of an optoelectronic system, and GRF data were measured by use of a force plate. Three-dimensional kinematic and GRF data were projected onto a 2-dimensional sagittal plane.
Results—Lame limbs had significantly lower peak vertical GRF, less flexion of the distal interphalangeal joint, and less extension of the metacarpophalangeal joint, compared with compensating limbs. Carpal joint kinematics did not change. Compensating limbs had a more protracted orientation throughout the stance phase and higher braking longitudinal force and impulse; however, total range of rotation from ground contact to lift off did not change. Transfer of body weight from lame to compensating limbs was smooth, without elevation of the body mass into a suspension phase. Propulsive components of longitudinal GRF did not differ between limbs.
Conclusions and Clinical Relevance—In horses with experimentally induced superficial digital flexor tendinitis, changes in vertical GRF were reflected in angular excursions of the distal interphalangeal and metacarpophalangeal joints, whereas changes in longitudinal GRF were associated with alterations in the protraction-retraction angle of the entire limb. (Am J Vet Res 2000;61:191–196)
Abstract
Objective—To determine whether analysis of net joint moments and joint powers is a suitable technique for evaluation of mechanics and energetics of lameness in horses and to measure effects of superficial digital flexor tendinitis.
Animals—6 sound horses.
Procedure—Horses were evaluated before (sound evaluation) and after (lame evaluation) induction of superficial digital flexor tendinitis in 1 forelimb by injection of collagenase. Recordings were made with an optoelectronic system and a force plate as horses trotted. Net joint moments and joint powers in the sagittal plane at each joint in the forelimbs during the stance phase were determined. Peak values were determined, and mechanical energy absorbed and generated at each joint was calculated. Comparisons were made between contralateral limbs during sound and lame evaluations.
Results—Lame limbs had significant reductions in peak values for net joint moments on the palmar aspect of metacarpophalangeal (fetlock), carpal, and humeroulnar joints. Total energy absorbed was significantly lower at every joint in lame limbs, compared with compensating limbs.
Conclusions and Clinical Relevance—Horses with superficial digital flexor tendinitis had significant differences between lame and compensating limbs for net joint moments and joint powers at all joints, indicating that the gait of horses with superficial digital flexor tendinitis is energetically inefficient. Assessment of net joint moments and joint powers is a useful tool in evaluating equine lameness. (Am J Vet Res 2000;61:197–201)
Abstract
Objective—To determine kinematic movements of the vertebral column of horses during normal locomotion.
Animals—5 Dutch Warmblood horses without apparent lameness or problems associated with the vertebral column.
Procedure—Kinematics of 8 vertebrae (T6, T10, T13, T17, L1, L3, L5, and S3) and both tuber coxae were determined, using bone-fixated markers. Horses were recorded while walking on a treadmill at a constant speed of 1.6 m/s.
Results—Flexion-extension was characterized by 2 periods of extension and flexion during 1 stride cycle, whereas lateral bending and axial rotation were characterized by 1 peak and 1 trough. The range of motion for flexion-extension was fairly constant for vertebrae caudal to T10 (approximately 7°). For lateral bending, the cranial thoracic vertebrae and segments in the pelvic region had the maximal amount of motion, with values of up to 5.6°. For vertebrae between T17 and L5, the amount of lateral bending decreased to < 4°. The amount of axial rotation increased gradually from 4° for T6 to 13° for the tuber coxae.
Conclusions—This direct measurement method provides 3-dimensional kinematic data for flexion-extension, lateral bending, and axial rotation of the thoracolumbar portion of the vertebral column of horses walking on a treadmill. Regional differences were observed in the magnitude and pattern of the rotations. Understanding of the normal kinematics of the vertebral column in healthy horses is a prerequisite for a better understanding of abnormal function. (Am J Vet Res 2000;61:399–406)
