The hock joint is made up of 4 main joint levels. It is common for a performance horse to develop arthritis of the two lower hock joints. These joints are very low motion joints that respond well to treatment with steroids and hyaluronic acid injected into the joints periodically. Arthritis of next joint up (proximal-intertarsal joint), is very rare, but career ending.
This patient is a 12 year old quarter-horse gelding that was used for barrel racing. He presented to Cave Creek Equine with a severe left hind lameness, and a large amount of fluid in the tibiotarsal joint (hock joint).
X-rays showed a severely narrowed proximal intertarsal joint. This reflects the loss of joint cartilage that normally separates the bones. This joint is part of the upper, high motion joint.
Normal Proximal-Intertarsal joint for comparison
Arthritis of the two lower hock joints is very common and treated successfully with periodic joint injections of corticosteroids and hyaluronic acid. In this case, the severe arthritis of the next joint up- the proximal-intertarsal joint, is not treatable. The prognosis for soundness in this horse is very poor.