Most performance horses will, at some point, develop problems with their lower two hock joints. Arthritis and inflammation of these joints can cause lameness and decreased performance. These joints are commonly treated with cortisone and hyaluronic acid in the joint to decrease pain and inflammation. Another treatment is to surgically remove the cartilage from the joint surfaces to allow the joints to grow together; this prevents pain in the joint and since these joints move very little anyway, performance is not affected.
A new treatment has been reported using 70% ethyl alcohol that is injected into the joints. This alcohol chemically destroys the cartilage in the joint and allows the joint to grow together, or ankylose, without surgery. Ethyl alcohol is essentially rubbing alcohol and it is certainly less expensive than surgery. A recent study was performed, and reported at the AAEP convention, in 11 horses that were proven to have arthritis in the lower hock joints. All were injected with 3cc ethyl alcohol and 10 of the 11 horses were still sound one year after the injections. This outcome is in contrast to injecting the joints with cortisone, which may last 2 to 3 months. It is interesting to note that none of the joints were fused but the horses were still sound so maybe the alcohol has an effect on the nerves that innervate (supply with nerves) the joint surface. The disadvantage of alcohol injection is that you must be very careful that all of the alcohol goes only in the lower two hock joints and does not enter the top joints, and that the alcohol does not diffuse in the soft tissue around the joint as a reaction could occur.