Common types of equine hock disorders:
Spavin has two forms: bog spavin or tarsal hydrarthorsis and bone spavin. Bog spavin occurs when there is chronic synovitis or excessive fluid accumulation in the joint capsule. As a result of these fluids the joint appear bloated. A predisposing condition to bog spavin is a faulty bone conformation resulting to a weakened hock joint. The body compensates to such weakness by increased production of synovia. A sprain may also stimulate increased synovia. Bog spavin does not usually interfere with a horse’s performance. However, it is an unattractive blemish especially in show horses. Treatment involves the aspiration of the excess synovia.
Curb occurs when there is a thickening or bending of the plantar tarsal ligament manifesting in the formation of a bulge over the cuadual surface of the fibular tarsal bone just below the hock. This bulge is most evident when one views a horse in profile. This condition develops after a traumatic activity such as slipping or falling. Some horses develop curb after excessive jumping or lunging. In such cases, apply cold compresses to lessen inflammation and rest the animal as soon as possible. If the cause of the curb is conformational, there is little to be done to fix the problem. Just like spavins, curbs do not seem to interfere with performance and are more of aesthetic concerns.
Stringhalt, also known as crampiness or stringiness, is an ill-defined disease with no known direct causes yet is associated with lesions in the sciatic, peroneal, and tibial nerves manifesting in the spasmodic upward lifting of the hindlimbs or grounding of the foot. It is most evident as an afflicted horse takes its first steps. In extreme instances, a horse is seen to jerk its foot so sharply that the limb actually touches the belly before being violently struck back to the ground. Many stringhalt cases recover spontaneously. In chronic or severe instances, tenectomy of certain limb muscles is required. Surgery is not always successful in alleviating stringhalt, thus, there are horse owners who opt for euthanasia instead.
Thoroughpin is a soft enlargement in the concavities just above the hock. Its fluctuating quality is attributed to fluid accumulations commonly due to traumatic causes. The enlargement can be pressed from one side to the other. Thoroughpin is considered a blemish implying that it is functionally harmless yet another aesthetic problem similar to a spavin. Treatment is by aspiration of fluids and administration of corticosteroid to reduce the swelling.
Fracture of the Tarsus
Causes of tarsal fractures can be traumatic in origin or a secondary complication of a joint disease. Since the hock is a joint made of several bones, it is susceptible to many types of fractures. Radiography is vital for accurate diagnosis of the type and location of the fracture. Frequent fractures include the tibiotarsal bone and either the left or right malleolus of the tibia.