What is Angular Limb Deformities (Foals) ?
Angular limb deformity is the term for crooked legs in foals. These can occur in any of the joints in the front or hind legs but are most common in the knees and fetlocks. Some deviations within the limbs are common in the first few months of life, and in many cases will be corrected with stall rest and proper hoof trimming. In severe cases, surgical intervention may be required which can include the insertion of plates, screws, or wires to stabilize the bones.
Angular limb deformities, also known as angular limb deviations, are misalignments of the leg in foals, particularly common during their first few months of life.
Symptoms of Angular Limb Deformities (Foals) in Horses
Angular limb deformities are usually visible to the naked eye when standing directly in front of or behind the young horse. Other symptoms that you may observe with these disorders include:
- Asymmetrical gait
- Bone collapse
- Excessive wearing of the hoof wall
- Heat at joints
- Inflammation of growth plate
- Joint swelling
- Stretched ligaments
Angular limb deformities in foals can be classified by the shape and placement of the angular deviation.
The term valgus refers to outward deviations of the limb that force the joint inward. Common disorders in this category can include being knock-kneed (carpal valgus), and cow hocked (tarsus valgus).
The term varus refers to inward deviations of the limb which force the joints outward. Common disorders that would be included in this classification would be bowlegged (carpal varus), and pigeon toed (fetlock varus).
In some cases, the foal has one limb that has a valgus deviation and another with a varus deviation. Foals with this configuration are referred to as windswept.
Causes of Angular Limb Deformities (Foals) in Horses
There are several circumstances that can lead to deviations in the limbs of foals. This can include situations like:
- Disproportionate growth
- Excessive exercise
- Inflammation of the placenta
- Maternal colic during pregnancy
- Perinatal tissue trauma
- Poorly developed ligaments or tendons
- Premature birth
- Trauma after birth
- Twin pregnancy
- Unbalanced hooves
- Unbalanced nutrition
Diagnosis of Angular Limb Deformities (Foals) in Horses
A visual examination may show that a problem exists, but more investigation is required to find out the origination and seriousness of the deformity. A full physical examination will be completed, including the manipulation of the limbs and assessment of the foal’s gait. The manipulation of the joint will reveal if any swelling, pain, or heat are emanating from the site, which may indicate that the disorder is due to physical trauma or infection. Physical injury can occur in foals even before birth, particularly in pregnancies with twins.
Radiography imaging will help to uncover a number of crucial factors in determining the best treatment plan for the specific foal. These factors can include things like the angle of the deviation, the condition of the bones in the joint itself, and the appearance of the growth plates. Ultrasound technology may also be used in order to evaluate the health and positioning of the tendons and ligaments.
Treatment of Angular Limb Deformities (Foals) in Horses
Treatment depends on the severity of the disorder, the underlying cause of the disease, and the age of the foal. Although dietary and exercise restriction and stall rest are standard treatments for all severities and ages, some treatments, such as trimming of the hoof wall or adding glue on extensions, are only really effective in foals that are three months old or under. This age is even younger in miniature horses as their growth plates close earlier than in their larger counterparts. Foals who have more severe deviations, or foals who are older, may require more invasive treatments to achieve straight limbs. The two most commonly employed surgeries include:
The goal of this treatment is the retardation of growth using screws and wires to bridge two bones thereby stopping growth on the faster-growing side of the bridge. It is valid for a few weeks longer in the foal’s growth than periosteal stripping but requires a second surgery to remove.
This treatment is used to cause growth acceleration and should be utilized early in the foals life. Stripping, or removing a portion of the bone using a t-shaped incision, is best utilized before eight weeks old for the fetlock, twelve weeks old for the hock, and sixteen weeks old for the knee.
Corrective Osteotomy or Ostectomy
This is used when the growth plates have already closed, and intervention is required. A wedge of the bone is removed, and the remaining bones are secured with screws and plates.
Recovery of Angular Limb Deformities (Foals) in Horses
The prognosis for foals with angular limb deformities will depend on the type of deviation, the severity of the deformity, the age of the foal, as well as the underlying cause. If surgery is required, daily monitoring will be needed to evaluate the leg for heat, swelling, lameness or pain. Additional visits with the veterinarian will also be required. Any sutures and screws or wires will need removal, and further x-rays will be necessary to evaluate the progress of treatment. A few major complications can occur with surgery, including overcorrection from growth retardation implements not being removed in time and infection of the bone.