Ask The Vet

Provided By: Melissa McKee DVM

How old is this horse? If it is a youngster, swelling in the hock joints can be the first sign that there is OCD, or chips, in the tibiotarsal joint (the uppermost joint which is the major hinge). Puffiness in this location is called bog spavin. Acute swelling of this joint in older horses usually indicates a sprain or soft tissue injury. Horses of any age can also have swelling in the lower “spavin” joints, but this is harder to detect because the joints have almost no motion and very tight joint capsules. There are also several fluid sacks, or bursas, around the hock including the cunean bursa on the inside and at ligament insertion sites at the top of the cannon bone. Inflammation in these can lead to stiffness and discomfort.
Another possibility is edema of the hind legs secondary to local or systemic infection that has a tendency to localize in specific spots as it slowly resolves.
In any event, if you want to investigate the cause of these swellings on the hocks, digital radiographs and ultrasound of the region would be informative.