Description

Knock knees, also known as carpal valgus, occurs when the entire knee of the horse is set to the inside based on the drawing of a straight line from the horse's chest to the toe of the horse. Knock knees are usually accompanied by toed-out feet and with some degree of outward rotation of the cannon and fetlock.

In a young foal, the growth plates are still active in the long and short pastern, the cannon bone, and the bone above the knee. If corrective measures are not taken while the bones are in their formative stage, knock knees will become more pronounced as the bones fuse, establishing a conformation that cannot be altered.

The growth plates close faster in the lower part of the limb, so it is important that any deviations, such as knock knees, are quickly assessed and dealt with as the bones grow and harden.

Symptoms

• Knees knock together when foal or horse walks or runs
• Instead of straight legs, knees turn in and feet toe out

Causes

Uneven growth of the leg bones of the foal is often the cause of knock knees. When the bones grow in an uneven way, other bones and muscles compensate for the uneven growth, creating deviations from healthy conformation of the limbs.

Prevention

Early recognition of developmental orthopedic problems, followed by consultation with a veterinarian and a program of appropriate treatment, is the best prevention for problems associated with knock knees.

Treatment

Treatment of knock knees will depend on the severity of the deformity, the age of the foal, and the location and angle of the deviation. A veterinarian experienced in working with orthopedic problems in foals should be consulted as soon as the problem is discovered. In some cases, a farrier will be called in to work with the veterinarian. .

One corrective measure is known as periosteal stripping, which supposedly releases the tension of the periosteum on the outer, concave side of the bone. Growth on the outside part of the growth plate is able to catch up with the growth on the inside, resulting in correction of the knock knees.

Another corrective measure is known as a tranphyseal bridge. Used for severe cases, a system of screws and wires is used to slow growth on the inside, but allow growth on the outside bones. The implants are removed when the legs straighten and the knees move into a straight line, usually within one to three weeks.

Other methods include a system of trimming, bracing, and wedging the hooves to alter support for the leg in such a way that it straightens and the knees move into a straight line. Some veterinarians use knee braces custom-fitted to the foal. Other options are surgery, epiphysial stapling, and the use of casts.

Continued exercise may be an important part of the treatment, but must take into consideration the abilities and needs of the foal. The services of a veterinarian and farrier familiar with orthopedic problems is very important in treating a foal with knock knees.