Page 172 - Speedhorse February 2020

EQUINE HEALTH
A fractured splint bone is sometimes mistaken for splint lameness, but in most cases a fracture has more swelling and the horse is lamer for a longer period of time. This problem is also most common on the inside of the leg, as a result of being hit by the opposite hoof when the horse is working at high speed.
and ligaments, and contains a layer of bone- forming cells. These cells play a role in growth and development of young bones, and in the repair of broken bones. The bone-forming
cells in the periosteum may be stimulated to form new bone if injured. Inflammation and increased blood supply to the injured area can trigger new growth. This can happen anywhere along the juncture between the cannon bone
and splint bone if the ligament attachment is pulled/torn.
“Whether or not a bony growth develops is often related to the severity of the injury,” says Baxter. This type of injury is generally due to excessive stress and strain on the structures, as when a young horse is being worked too hard or has poor leg conformation that puts extra strain on the inner splint bone.
“A horse may also develop a splint from external trauma, as when a horse interferes
and hits himself with the opposite foot. This may or may not be due to poor conformation.” If he strikes the splint bone, this may create injury and inflammation. Horses that are splay-footed (toe-out conformation) tend to swing the feet inward when they are in motion, and often interfere, as will some horses that
are improperly shod—with feet out of balance. Exercising a young horse in small circles, such as lunging, may also contribute to splints.
Not only is the horse apt to strike himself, but circling also puts more stress on the inside of the legs.
Splints may be due to immaturity and hard work. If a trainer overdoes the work, there
may be tearing of the interosseous ligaments. Anything that excessively loads that inner splint bone can contribute to the formation of splints, and this includes poor conformation of the front legs.
Splints that occur on the hind legs are usually due to trauma, rather than from concussion and strain, and are much less common than splints on the front legs. Front legs bear more weight and must withstand more stress. When splints do occur on the hind legs from overwork, they are usually on the outside of the leg because the outside splint bone bears more weight and stress—with more potential for movement—which is just the opposite of what happens in the front legs.
LAMENESS
If the splint is acute, there will be heat, pain and swelling over the affected area. “Any pain on palpation, on the inside aspect of that inside splint bone area on a young horse, should make us suspicious of a splint. That would be our first thought, regarding the cause of lameness,” says Baxter. The horse may walk sound, but will likely be lame on that leg when trotted, especially on firm ground.
“Sometimes the swelling can become very large and contribute to chronic lameness. The question is always asked if the lameness is due to how large the bony enlargement is, or which way it grows. This can be problematic. If it grows inward, the bony enlargement may cause irritation to the main suspensory ligament or the tendons in that area. Depending on which direction the bony enlargement goes, it might cause some lameness by impinging on some
of the other structures, or just from the bony lump itself,” he explains.
Many splints resolve with time and rest, without treatment. The inflammation, swelling and lameness disappear, and the horse may
or may not have a bony lump in that area.
The length of time it takes for the horse to become sound again will depend on the type and severity of the splint. It may be two weeks, or two months—or longer. Healing can be hastened if the inflammation can be reduced in the early stages.
TREATMENT
For a bony growth that is impinging on moving parts, part of the lump can be shaved off surgically. “Even if it is right up against the knee, you can’t take out all of the splint bone because it is fairly supportive of the knee joint, but a veterinarian can surgically remove part of it with a chisel and mallet to take off the bony growth and smooth it up, to make the horse
“The best way to prevent splints is to take it slow with young horses
in training, and not be in too big a hurry.”
Exercising a young horse in small circles, such as lunging, may also contribute to splints. Not only is the horse apt to strike himself, but circling also puts more stress on the inside of the legs.
170 SPEEDHORSE, February 2020