I’m new to the equine industry and my mare just had her first foal 3 weeks ago. The foal was born with crooked legs. The front legs are splayed out from the knee down. I’m worried the filly will never be able to be useful. Is there anything I can do?

There is a common saying by equine veterinarians that “all foals are born crooked and should be expected to straighten out.” Think about human babies. When they first start walking, almost all are bowlegged and within a few months the legs straighten.

The condition you are describing is called an angular limb deformity (ALD). In your foal, this is commonly looked at as a knock kneed condition. Medically this is called carpal valgus.

This lateral deviation of the limb distal to the carpus (knee) is the most common angular limb deformity seen in foals. Others seen happen from the fetlock down or distal to the tarsus (hock).

Many times the exact cause is unknown. Since your foal was born with this condition, it is said to be congenital.

It could be that the foal was born with incomplete development of the small bones (cuboidal bones) within the carpus or laxity of the tendons or ligaments that would normally hold the leg in a straight position.
If the condition is due to weak tendons or ligaments, it should correct itself as the foal exercises. However, if the cause is due to incomplete development of the cuboidal bones, they run the risk of crushing these bones with exercise.

Some foals develop this condition when they are a few months old. These foals usually have an abnormal growth plate where one side of the leg is growing faster than the other. This is called a developmental ALD.

Your veterinarian should examine your foal. He/she may be able to manipulate the limb to determine if the condition is caused by weak ligaments. The veterinarian may suggest radiographs to determine if the cuboidal bones are properly developed. Based on his/her findings and the severity of the angular deviation, your veterinarian may suggest limiting exercise until the bones fully develop.

A high percentage of foals with ALD respond favorably to conservative management, including rest or restrictive exercise.

If the carpal ALD becomes worse or does not show improvement, there are surgical treatments.

Surgery is more commonly utilized in foals with a developmental ALD. Depending on the severity the veterinary surgeon may suggest a surgery to “speed up the growth” on one side of the growth plate, or “restrict the growth” on the side growing too fast.

With appropriate treatment the vast majority of these foals develop into normal horses able to perform normally. Several years ago, the winner of the Kentucky Derby had previous surgery for an ALD. Good luck with your foal and follow the advice of a veterinarian with experience with this condition.

This column is provided by the faculty of the OSU Boren Veterinary Medical Teaching Hospital.

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