(Editor's Note: The following is excerpted from Understanding The Foal, a book by Christina S. Cable, DVM, Diplomate ACVS, and one of the series of books in The Horse Health Care Library.)

I'll never forget the night I received a phone call from a very unhappy man about his three-day-old foal. He said the legs weren't made right, and he wanted reassurance that euthanasia was the right solution. I couldn't give him an opinion without examining the foal, but he said his veterinarian already looked at it and three days of physical therapy had not improved the problem. I eventually convinced the man to bring the foal into the clinic. Although the foal had trouble standing on its own, I thought we might be able to help him. The foal's fetlocks and coffin joints were badly flexed, but we custom-made splints out of PVC pipe. This helped tremendously, but he needed a little more help, so we performed surgery to cut the check ligaments. This did the trick and the foal went home with new legs. The foal is perfect today, and the owner is very happy.

Flexural or angular deformities can be very shocking and even disturbing in severe cases, but appropriate veterinary care offers great hope for these foals. Flexural deformities can be classified into two categories. The first is flexor tendon laxity, which causes the neonatal foal's fetlocks to drop. The second type is flexural contractures, which is flexion of any of the lower limb joints.

Flexor Tendon Laxity

Flexor tendon laxity usually occurs in newborn foals, but can occur in slightly older foals. This laxity can range from a slight drop in the fetlock to the fetlock(s) actually touch the ground. Flexor tendon laxity is common in premature or dysmature foals. This doesn't necessarily mean that if your foal has lax tendons, that he/she is premature/dysmature. Mild laxity usually resolves on its own as the foal gets stronger and exercises--often within a few days to one week. If the laxity is more pronounced, then hoof trimming to create a flat, weight-bearing surface is very beneficial.

Cases of severe laxity require more care, and the foal should be evaluated by your veterinarian.

First, the foal's lower limb (heel, pastern, and fetlock) must be protected when it moves or bruising and wounds can develop, which create a source for infection to develop. Bandaging the lower leg before turnout or hand walking is imperative because sores can develop even on a soft surface. Make sure that the foal is kept in a well-bedded environment when in a stall; clean wheat straw is ideal.

Second, if trimming does not help get the foal's heels off the ground, then special shoes are required. The special shoes are some form of shoe with a heel extension. My favorite is a glue-on shoe with a heel extension. These shoes stay on well even when the foal exercises. Foals should not wear these shoes for more than two weeks at a time or hoof contracture could develop. Other options include gluing small pieces of plywood to the hoof. Small foals such as miniatures can be treated with tongue depressors glued together, then taped or glued to the hoof. Treatment usually succeeds once the heels are elevated, but it helps for the veterinarian and farrier to have a good working relationship.

Flexural Contractures

Flexural contractures often are referred to as "contracted tendons." This is because when the affected foal stands, it appears that the tendons are tense and too short, but this isn't a complete explanation of the problem. This deformity can be present at birth (congenital) or develop in the older foal (acquired). The source of this problem in the newborn is not completely understood, but is thought to be caused by malposition of the foal within the uterus. However, nutritional abnormalities and even genetics have been implicated as some mares produce multiple foals with flexural deformities.

Flexural contracture results in the flexion of the joints of the lower limb(s). The joints most commonly affected are the carpus, fetlock, and coffin joint. One or multiple joints or legs can be affected. Flexural deformities also can occur in older foals, known as an acquired flexural deformity. Treating this type of deformity depends on the severity. Mild cases of flexural deformities can resolve on their own with light bandages and exercise. Moderate cases might need splinting and/or casting with the hoof exposed, called tube casting.

Treatment with oxytetracycline (an antibiotic) has been used with a fair amount of success in relaxing the tendons, but requires careful administration because of the potential toxic effects to the kidney. Surgery also might be required to help the foal's legs return to normal. Severely affected foals, especially those which cannot stand because joint(s) are fixed in position, might have other congenital birth defects such as spinal cord disorders. Euthanasia is the best alternative in those cases.

Flexural Contractures Acquired

These types of contractures occur in older foals and in fairly specific locations. Young foals (one to six months) might develop contracture at the coffin joint. Older foals (at least three months as well as yearlings and occasionally 2-year-olds) might develop contracture at the fetlock joint. These contractures occur in the forelegs, usually in both (bilateral), except for cases where the contracture in one leg is due to lack of use because of pain. The cause is not completely understood and is thought to be related to over nutrition (excessive carbohydrate and/or protein content) and/or mineral imbalances. Treatment depends on the severity of the disease, but should begin as soon as possible.

Club Foot

Acquired flexural deformity of the coffin joint often is referred to as "club foot." The foot can vary from a dished appearance with the heel raised to a boxy shape with the hoof wall nearly perpendicular to the ground. In very severe cases, the foal or horse might walk on the front (dorsal) aspect of the hoof or fetlock. Mild cases might require only a decrease in nutrition; in young foals weaning might work. Hoof trimming, along with a shoe with an extended toe, might be necessary.

If this conservative therapy does not work, then surgery to cut the inferior check ligament is warranted and often successful. Severe cases often do not respond well to treatment, including surgery, unless the entire deep digital flexor tendon is cut, which is a salvage procedure only. The prognosis for athleticism in these cases is guarded.

The key is beginning treatment early. A delay in diagnosis or treatment can lead to undesirable results. Young foals should be evaluated on a daily basis to ensure that they are not developing contracture or other orthopedic problems.

Angular Limb Deformities

Angular limb deformities are deviations that occur from side to side, such as when the leg deviates from the carpus, tarsus, or fetlock to the outside (laterally) or inside (medially). A lateral deviation is called a valgus deformity and a medial deviation is called a varus deformity. These deviations are extremely common and can be congenital (present at birth) or acquired (develop later in the foal's life). There are several primary reasons angular deformities occur.

  • Unossified bones of the carpus and tarsus due to prematurity or dysmaturity.
  • Laxity in the soft tissues surrounding a joint and muscles.
  • Abnormal uterine positioning.
  • Uneven growth at the physis (growth plate) of long bones.
  • Rapid growth.
  • Trauma.

A physical examination by your veterinarian as well as radiographs will help determine the cause. Radiographs allow for evaluation of the bones to ensure that they are formed completely. Radiographs also allow for documentation of the degree of angulation. Many foals, especially Thoroughbreds, are born with a mild angulation to both carpi. This usually will correct spontaneously during the first month of life.


Soft tissue laxity can lead to some very severe deformities. These types of deformities are most easily corrected with the use of tube casting, which allows the foot to be exposed. These casts keep the affected joints in a normal position until the soft tissue structures become stronger and can support the joint.

Unossified carpus or tarsus (hock) bones also are treated by tube casting. Without cast support, the incompletely formed bones cannot bear the weight of the foal and can become crushed, which is referred to as carpal crush or tarsal crush syndrome.

Surgical Treatment

If the angular deformity does not correct on its own within a few weeks or is moderate to severe, then surgical therapy should be attempted. Surgery to treat these deformities involves one of two procedures. Periosteal elevation helps stimulate growth. The procedure is used when there is uneven growth and one side of a long bone is growing at a faster rate than the other, leading to an angular limb deformity. This procedure involves making an incision in the periosteum (the covering of the bone) on one side of the bone. This is a rather simple surgical procedure, has little risk involved, and good cosmetic results. Many times, this procedure will be performed early in a foal's life, even on those with only mild deformities, just to ensure that the leg(s) become straight.

The second type of procedure is called transphyseal bridging. This involves placing screws and wires or orthopedic staples to slow growth on one side of a growth plate. This is used for moderate to severe deformities. The procedure's disadvantage is that the implants (screws and wires or staples) must be removed during a second operation. The foal requires close monitoring as the implants, if left in place too long, actually can cause the foal to over correct, leading to a angular deformity in the opposite direction. The implants must be removed as soon as the leg is straight.

The trick with angular limb deformities is timing. Angular limb deformities, even severe ones, can be corrected, but the foal must be treated at the appropriate time for that joint. Improper timing can result in a residual deformity, which might decrease the foal's value as a sale yearling or lead to early joint degeneration due to abnormal loading. Deformities of the carpus and hock should be corrected within four months of life. However, most corrective surgeries are performed between two and four weeks of age to ensure correct conformation.

Deformities of the fetlock are much more critical as the rapid growth phase is much shorter in this area, therefore not allowing as much time for correction as in the carpus or tarsus. These deformities should be addressed by one month of age. It is always tragic to see a beautiful weanling whose confirmation was ignored until preparations get under way for sale. But then, it is just too late. Have your veterinarian evaluate your foals early. Correct conformation goes a long way in preserving soundness in any discipline.

Hoof Care

Another aspect of foal management that too often goes ignored is good hoof care. Some people overlook hoof care because foals are usually not forced to exercise. Foals which spend a lot of time outdoors will keep their hooves worn down to a certain extent. But all foals need to have their hooves trimmed regularly. Foals with abnormally shaped hooves or those with rotational or angular limb deformities require trimming every three to four weeks to correct their problems.

If you are unsure if your foal has a problem, you should consult with your veterinarian and farrier as soon as possible. Furthermore, teaching the foal to stand for a hoof trim will make future farrier work less stressful.

About the Author

Christina S. Cable, DVM, Dipl. ACVS

Christina S. Cable, DVM, Dipl. ACVS, owns Early Winter Equine in Lansing, New York. The practice focuses on primary care of mares and foals and performance horse problems.

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