Effect of heel elevation on forelimb conformation in horses.
OBJECTIVE
To determine the conformational changes in the distal forelimb of horses following heel elevation of 15 degrees and greater. An experimental study with repeated, within-horse measurements.


METHODS
Five clinically normal, mixed-breed horses were used to determine distal forelimb conformation following heel elevation from 0 to 45 degrees in 15 degree increments. Data were also compared to conformation of the limb in a Kimzey splint. Conformation was determined using lateral to medial radiographic projections. Conformation parameters assessed included measurement of apparent lengths of digital flexor tendons from the origin of their accessory ligaments to the points of insertion, and the joint angles of the distal limb.


RESULTS
For angles of heel elevation from 15 to 45 degrees, the degree of joint angulation increased (increasing flexion) with heel elevation for the metacarpophalangeal, and proximal and distal interphalangeal joints. Conversely, the measured apparent lengths of the digital flexor tendons in the distal limb, decreased.


CONCLUSIONS
The data supports the practice of elevating the heel (greater than 15 degrees) for conditions in which decreased fetlock extension may be desired such as with laceration or injury to the digital flexor tendons. Further study is required to determine whether heel elevation greater than 15 degrees reduces in vivo digital flexor tendon tension and also to ensure that the marked flexion of the distal interphalangeal joint with greater heel elevation is not detrimental over a prolonged period that may be required for the rehabilitation of flexor tendon injuries in the horse.
Department of Clinical Studies, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
S G
SG
Pearce
L P
LP
Boure
A
A
Bolger
J J
JJ
Thomason
H
H
Dobson
D000818:Animals; D001696:Biomechanical Phenomena; D005260:Female; D005552:Forelimb / Q000502:physiology; D006736:Horses / Q000502:physiology*; D008022:Ligaments / Q000502:physiology; D008124:Locomotion / Q000502:physiology; D008662:Metacarpophalangeal Joint / Q000502:physiology*; D012016:Reference Values; D013710:Tendons / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology*