Objective—To develop a method that allows quantification
of the 3 anatomic rotations in the digital joints
of moving horses and measure these rotations when
horses are walking in a straight line on a hard track.
Animals—4 healthy French Trotter horses.
Procedure—Triads of ultrasonic kinematic markers
were surgically linked to the 4 distal segments of the
digits of the left forelimb of each horse. Three-dimensional
(3-D) coordinates of these markers were
recorded in horses walking in a straight line. The three
angles of rotation of each digital joint were calculated
by use of a joint coordinate system as well as the 3-D
orientation of the hoof and third metacarpal bone. A
calibration procedure was developed to convert data
from measurements within a technical coordinate
system to data in relation to an anatomically relevant
Results—Precision of the method was 0.5o, and
repeatability of the calibrations resulted in variations
of 1.4o. Extrasagittal movements of the proximal and
distal interphalangeal joints were obvious during landing
because the impact of the hoof was on the lateral
side. Mean ± SD extension of the proximal interphalangeal
joint was 10.0 ± 2.5o.
Conclusions and Clinical Relevance—This study provides
a description of the technical background, error
analysis, and procedures used to measure the
3-D rotations of the 4 distal segments of the forelimb
in walking horses. As a major result substantial
involvement of the proximal interphalangeal joint in the
sagittal and extrasagittal planes,should incline investigators
and clinicians to consider the functional importance
of this joint. (Am J Vet Res 2004;65:447–455)
OBJECTIVE To evaluate the effect of track surface firmness on the development of musculoskeletal injuries in French Trotters during 4 months of race training.
ANIMALS 12 healthy 3-year-old French Trotters.
PROCEDURES Horses were paired on the basis of sex and body mass. Horses within each pair were randomly assigned to either a hard-track or soft-track group. The counterclockwise training protocol was the same for both groups. Surface firmness of each track was monitored throughout the training period. Radiography, ultrasonography, MRI, and scintigraphy were performed on all 4 limbs of each horse before and after 2 and 4 months of training. Lesions were described, and lesion severity was classified with a 5-point system, where 0 = no lesions and 4 = severe lesion.
RESULTS 86 lesions were identified, of which 46 (53.5%) were classified as potentially clinically relevant (grade, ≥ 2). Of the 18 moderate and severe lesions, 15 were identified in horses of the hard-track group, and 10 of those were in forelimbs. Moderate to severe tendinopathy of the superficial digital flexor tendon of the forelimb developed in 3 of the 6 horses of the hard-track group but none of the horses of the soft-track group. Metatarsal condyle injuries were more frequent in horses of the hard-track group than horses of the soft-track group. Severe lesions were identified only in left limbs.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that track surface firmness is a risk factor for musculoskeletal injuries in horses trained for harness racing.