Introduction

Farriers who routinely treat angular limb deformity and flexural deformity in foals will work in co-operation with equine veterinary surgeons experienced in these conditions. The objective is early detection, effective reversal of both angular and flexural limb deformity, restoring the foal to normal healthy conformation and development.

The greater part of managing foal development is affected by diet, exercise and how well the foal thrives on the mare, but there is a fine balance that can easily be tipped the wrong way resulting in deformity. The farrier’s role is highly valuable in maintaining, detecting and correcting deviations from the norm, when necessary. These conditions are divided into angular limb deformity (ALD ) and flexural deformity (FD). Beginning with ALD , deviation from the normal alignment of the foal limb either medially or laterally. (This is not limb rotation, which is untreatable by the farrier.) These conditions may be present at parturition and could be congenital, or are acquired as the foal develops, often when the foal is growing rapidly.

Classification

ALD s are described as either valgal, where the deviation occurs lateral to the axis of the limb or varal where deformities occur when the deviation is medial to the axis of the limb (Ref: Greet, 2000). This can occur at any of the joints of the limb but predominantly the fetlock and carpus or tarsus (knee or hock). The point of deviation is at the physis (growth plate) and not the articulation. These are located at the distal end of the radius at the knee and tibia at the hock. At the fetlock there are physes, both above and below the articulation at the distal end of the large metacarpal and the proximal end of the proximal phalanx (the long pastern bone). These deviations can affect one joint only or more. Cases may arise that are carpal valgus (medial deviation of the joint) and fetlock varus (lateral deviation) simultaneously, resulting in ‘zig zag legs’. Epiphysitis, inflammation of the epiphysial cartilage (growth plate) is likely when subjected to unequal forces or excessive concussion; it is visible as swelling just above the joint or below as the case may be. It can also be induced by over correction, excessive leverage caused by a large extension. This is where farrier, veterinary surgeon and stud manager need to work closely to obtain the desired outcome. A foal born with windswept limbs has valgal deformity in both the tarsus (hock) and fetlock in the one limb and varal deviation in both joints in the other hind limb.

Angular limb deformity treatment

This may be carried out in tandem with veterinary drug and surgical interventions such as periosteal stripping or stapling one side of the growth plate. The first line of treatment is hoof trimming to counter any perceived misalignment of the normal limb. It is worth noting that many neonatal (newborn) foals stand ‘A’ frame and appear slightly carpal valgus; this is normal. As they develop and broaden in the chest, the limb will also straighten up, as with lateral rotation of the forelimbs. So, frequent trimming of one side of the hoof, ie, carpal valgus – trimming the lateral side is advised. With carpal varus, trimming of the medial hoof wall may be all that is required to bring the limb back into axial alignment.

When this is ineffective then additional intervention in the form of adding material to the low or close side to create more depth and side extension puts material where ideally the foot needs to be. Priority for ALD correction is from the lower limb proximally. Correction within the rapid growth periods is essential.

Flexural deformity, club foot (acquired)

Apparent contracture of the flexors of the limb, possibly a disparity of development between bone and tendons. So called ‘Ballerina Syndrome’ refers to a foal that stands on tiptoe, heels off the ground. The hoof pastern axis (HPA ) becomes broken forward to varying degrees. This condition can develop rapidly; the deep digital flexor tendon (DD FT) is primarily involved. Flexor contracture may be present at birth, but often develops at a later stage such as during a growth spurt.

Club foot treatment

Once the condition is beyond trimming alone then toe protection, both solar and around the wall is desirable. Dependent upon severity, veterinary surgical
intervention may also be required in the form of a sub carpal check ligament desmotomy to re-instate normal extension of the limb.

After foot preparation and required Imprint Hoof Repair material is added to the foot, the completed job should position the foal with the heels on the ground or within 6mm to 8mm at most. The foal should be comfortable. Often the heels will drop quickly due to the sole protection newly in place, alleviating pain in that area.

Attention is recommended every couple of weeks unless otherwise indicated. NB This treatment is carried out as only part of the resolution of this condition. Diet and exercise and possible veterinary intervention are essential

Flexural deformity – flexural flaccidity

This condition is most common in the hind limbs, but any can be affected. Premature, weak or very large foals affected present like this at birth. The toe will be raised off the ground and the pastern at a low angle or lying along the ground with the fetlock on the floor in more severe cases. Many will firm up within days or in a week or two without farrier intervention. When severe or not recovering after a couple of weeks, Imprint caudal/palmer heel extensions, made using Imprint Hoof Repair material are likely to be required to assist the toe to the ground and raise the pastern angle.

Treatment

Extensions need to be well attached as there is substantial leverage brought to bear on them, so a shoe or all over attachment to the hoof is desirable. Using the Imprint method of attachment the micro-indentations are made no more than 1 mm deep, as these feet will be immature. With foals only a few weeks old this procedure can be successfully carried out without creating indentations.

The bulbs of the heels may be sore from weight-bearing instead of the soles, so care not to cover or pressurise them is important when fitting the extension. Often a heel extension half to three quarters the length of the foot will be sufficient to do the job.

An Imprint Foal shoe at least as big as the foot or larger is used. The foal’s foot will be growing rapidly in all dimensions, so the procedure may need repeating at two or three weeks, if the extensions are left on for a month, the hoof begins to become constricted. Each time the process is repeated a larger size of shoe is used. The extension is prefabricated onto the shoe before fitting. (See in Downloads, Prefabrication of a caudal heel extension using Imprint Hoof Repair material)

There is no need for metal or any other form of further reinforcement to the extension. All manner of foals from Shetland to Shire have been successfully treated by this method and the cases are usually resolved within a relatively short time.

Instructions for Imprint Foal shoe fitting and related procedures can be found under Resources.

Reference
Greet T.R.C. (2000) AAEP
Managing Flexural and Angular Limb Deformities