knee can be corrected by applying pressure with one hand on the inside of the knee and counter pressure with the other hand applied to the outside of the fetlock, then a splint made from polyvinylchloride (PVC) pipe fitted from the elbow to the fetlock applied for a few hours daily may be useful. A full‐length bandage is applied to the limb first, and then the PVC pipe is placed on the outside of the limb and secured with a bandage. This will distract the carpus laterally. The splint is often the most cost‐effective treatment available, but must be applied with caution. Mild to moderate valgus will generally respond to restricted exercise and the use of a composite extension applied to the medial side of the foot, while the more severe cases require surgical intervention combined with farriery. The extension on the medial side and toward the heels redirects the forces on the physis on the overloaded side of the limb by moving the plane of weight bearing toward the *Figure 2b midline (Figure 2b).3 The extension also promotes centerline breakover. The extension can be made from any number of materials. The material is applied directly to the foot and shaped to the desired width. It is trimmed like normal hoof as the foot grows distally, or additional applications can be applied if necessary. In severe cases of carpal valgus where surgery is necessary, a medial extension is combined with the surgery. Carpal valgus angular limb deformities respond well to surgery. Intervention up to four months of age has an excellent prognosis for full correction. After four months, the prognosis is dependent on the severity of the deformity and the age of the horse when correction is attempted. Varus deformities usually involve the fetlock in either the front or hind limb of foals. This deformity can be congenital or acquired within the first few weeks of life. A varus fetlock deformity requires early detection and treatment, as functional closure of the distal physis of the third metatarsal/metacarpal bone is approximately twelve weeks of age. Foals with fetlock varus should have their exercise restricted and will generally respond to an extension applied to the lateral side of foot. The window of opportunity for treatment is small and the extension should be applied at 2‐3 weeks of age. Caution must be used because the exothermic reaction of the extension materials could damage the sensitive tissues of the young foal. In severe cases, surgical intervention will be necessary, combined with an extension. If the foal is presented for treatment after thirty days of age, treatment becomes difficult and less effective. Flaccid tendons, tendon laxity. Flexor tendon flaccidity is a relatively common limb deformity seen in newborn foals usually involving the hind limbs, but may affect all four limbs (Figure 3a). This condition is thought to be the cause of digital hyperextension, where weight‐bearing is on the palmar/plantar aspect of the phalanges and the toe of the hoof is raised off the ground. The 8 The Practitioner
condition often tends to selfcorrect within days after birth as the foal gains strength and is allowed moderate exercise. However the tendon laxity can persist. It is not uncommon to see a foal that still has digital hyperextension at 4 weeks of age. Treatment is *Figure 3a sequential depending on the severity of the tendon laxity and the response of the foal to treatment. Therapy is based on controlled exercise and therapeutic trimming plus shoeing (if necessary). The foal is allowed access to a small area with firm footing for one hour three times daily. The toe of the foot can be shortened and the *Figure 3b heels can be rasped gently from the middle of the foot palmarly/plantarly to create ground surface, and a palmar/plantar extension can be applied if necessary. This extension which extends approximately 3‐4 centimeters behind the bulbs of the heels immediately relieves the laxity (Figure 3b). There are several different shoes that have appropriate extension that can be used. Although some apply these with adhesives, many believe that in these young foals shoes should only be taped on. It is believed that the heat generated by composites as they cure may damage the sensitive tissues of the hoof in foals less than 3 weeks of age. Regardless of the method of application, the extensions should be changed at 10‐day intervals. Bandaging the limb is contraindicated as this will cause further laxity of the tendons. Flexural deformities. Flexural deformities have been traditionally referred to as "contracted tendons." But this is a misnomer, as the primary defect is a shortening of the musculotendonous unit, not a contraction of the tendon portion, making "flexural deformity" the preferred term.1,4 This shortening produces a unit of functional length less than necessary for normal limb alignment of the digit, resulting in fixed flexion of the various joints of the distal limb, especially the distal interphalangeal joint. Congenital flexure deformities are thought to result from intrauterine positioning, genetics, nutritional management of the mare during gestation and the influenza virus, but no causes have been proven. These deformities involve a combination of joints in the distal limb causing the foal to assume a "ballerina" stance with weight‐bearing on the toes. Congenital flexure Issue 2 • 2015