2938 Vet. Med. Basic Sciences Bldg.
2001 S. Lincoln Ave.
Urbana, Illinois 61802
By Linda March
University of Illinois
College of Veterinary Medicine
She's a winner! So cute and wobbly, can hardly gather those legs under herself. The weeks pass and she's still not able to get it all together.You get worried and talk to your veterinarian.
According to Dr. Phil Hammock, an equine veterinarian at the University of Illinois College of Veterinary Medicine at Urbana, "An angular limb deformity is any deformity that affects the straightness of the horse's leg from the shoulder to the foot."
It's normal for foals to be born with wobbly legs. Owners should initially wait a week or two if they notice a deformity. Often the foal will gain strength during that time and the legs will straighten out on their own. If they don't, call your veterinarian.
It is important to correct deformities before the growth-plate closes. When the fetlock is the joint affected, the problem needs to be corrected before the foal is 10 weeks old, usually at 2 to 3 weeks of age. If it is a carpal deformity, the correction can be done between three to six months, but earlier is usually better if the deformity is severe.
When evaluating for angular limb deformities (ALD), the horse is viewed from the front. One should be able to draw an imaginary line from the center of the hoof up to the center of the shoulder. With ALD there is a deviation of the leg, either inward or outward. The most common joints affected are the fetlock, the hock and the carpus.
Angular limb deformities can be congenital or acquired. Congenital means the foal is born with the condition. At the time of birth, or within a few hours, the owner can see a turning in or out of the leg. When ALD is acquired, the foal was normal at birth, but something has happened to cause the limbs to grow at an angle. Generally, acquired ALD is due to trauma (some injury) to the leg. Often the injury affects the physis (growth plate) of the bone, causing one side of the bone to grow at a slower rate than the uninjured side.
"Big, fast-growing foals are more likely to have acquired angular limb deformities," Dr. Hammock notes, "These horses are growing so fast, they are just more prone to physeal trauma which can result in ALD."
Surgery is one treatment option. The procedure used most often is called periosteal stripping. The periosteum (top layer of the bone) is lifted away, from the underlying bone. It is thought that the combination of physically releasing the pressure on the growth plate and interrupting the blood supply to the bone have the desired effect of allowing the bone to grow faster on one side, thus straightening the limb.
Another surgical procedure is trans-physeal bridging. Orthopedic screws and wire are placed in or around the growth plate to slow bone growth on one side, thus allowing the limb to straighten. Periosteal stripping is often done in conjunction with this procedure.
Controlled exercise and slowing down the growth with a restricted diet are two conservative treatments that may be tried to correct ALD.
"Casting the leg is seldom done any more," states Dr. Hammock. "Now we use glue-on shoes."
If you and your veterinarian decide to use glue-on shoes, the foal should show improvement very soon. If there is no improvement after about two weeks, then the next step is usually surgery. If the ALD is severe, surgery and corrective shoeing may be used simultaneously to treat the disorder. The prognosis for angular limb deformities is usually good if treated promptly.
If you have any questions about angular limb deformities,
call your veterinarian.