The Effect of WEDGED PADS
It is not uncommon for veterinarians to recommend the application of wedged pads, especially in horses with broken-back distal limb axes and/or issues related to flexor tendon tension. The ramification of this recommendation, however, is that the farrier is now faced with the quandary of increasing the horse's distal limb angle without compromising the heel quarters of the foot. This is one of many reasons why your farrier may not be excited to work with your veterinarian.
Your farrier knows that the closer that the limb's center of gravity is to the limb's center of weightbearing, the better for the foot.
The limb's center of gravity is primarily dictated by the body's center of gravity coupled with the horse's body/ limb conformation.
In the horse's thoracic (front) limb, the center of gravity (roughly associated with the medial aspect/ inside of the cannon bone) typically falls behind and to the inside of the foot. The limb's center of weightbearing, therefore, is along the palmaromedial (back and inside) portion of the foot. In other words, the inside of the foot generally bears more weight than the outside of the foot and the back of the foot generally bears more weight than the front of the foot.
As we elevate the heel and increase the angle of the hoof (through the process of wedging), the fetlock joint will tend to "drop" due to decreased flexor tendon tension. As the fetlock drops, weightbearing tension is transferred from the flexor apparatus to the suspensory apparatus.
As the fetlock drops, the cannon bone (and therefore the limb's center of gravity) moves further behind the foot from a horizontal standpoint. With this orientation, the distance between the limb's center of gravity and the limb's center of weightbearing has increased. Consequently, a greater compressive force is experienced at the center of weightbearing, which in this case is along the horse's heel quarters. It is for this reason that wedged pads often result in "crushed heels", a problem that most farriers wish to avoid.
Myron McLane, a farrier from Somerset, MA has developed a solution to this long-term quandary. Myron has developed wedged pads that employ a dropped-frog component intended to reduce compressive weightbearing stress to the heel quarters. By directly incorporating frog pressure, the pads create an environment that counteracts the deleterious effects of regular wedged pads. Extra compression typically borne by the heel quarters is effectively transferred to the frog, thereby reducing the risk of "crushed heels".
Since their introduction several years ago, Myron McLane wedged pads have allowed us to both improve and accelerate heel growth in the face of wedging... an objective previously not feasible in most instances.
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