Let’s face it; most horses have to do a job for us. Whether it’s fulfilling our dreams as show performers or just carrying us up a steep and beautiful trail, they need to perform.
Osteoarthritis/synovitis or degenerative joint disease is very common in working horses and can cause a performance limiting lameness. Joint injections are sometimes done to help decrease the pain and inflammation of joint disease and return horses to sound work.
Once inflammation begins to affect a joint, either by a traumatic one-time incident or the repetitive stress injury of performance, the horse’s inflammatory system actually perpetuates the disease. The body releases enzymes in response to the inflammation and these enzymes damage the joint capsule and cartilage in the joint. So the pain of the degenerative joint disease is caused by both an outside and an inside force.
The reason we inject corticosteroids into the joint is because they are powerful anti-inflammatory drugs and they shut down the enzymatic attack on the sensitive structures of the joint (cartilage and joint capsule). This causes a dramatic relief of joint pain and a temporary cessation of the processes of destruction. But because they are such powerful drugs, we need to use them judiciously. Veterinarians try to pick specific kinds of cortisones for specific joints and use the lowest effective dose. We also limit exercise, and therefore trauma, while the chemical is working in the joint.
Hyaluronic Acid (HA) is a compound that is commonly added to cortisone when injecting joints. It adds another “healing” element to the cortisone and helps nourish the joint by reducing friction, stimulating the joint capsule to produce better joint fluid, reducing enzyme release, and providing pain relief. Hyaluronic acid has also been thought to prolong the anti-inflammatory effect of the joint injection when mixed with cortisone. So although it may increase the cost of injection, the effects of the injection will last longer.
Joint injections have gotten, and in some cases continue to get, a bad rap. People think that cortisone actually hurts joints more than it helps. Studies done 8-10 years ago refute that claim. Researchers at Colorado State University did studies on the 3 most commonly used corticosteroids and actually showed either no harm to the joint or, in the case of triamcinolone, chondroprotective properties. As I explained above, cortisone actually shuts down the processes that harm the joint. Nevertheless, we don’t get cavalier about the procedure; we rest the horse after injections so the drugs can do their thing and leave the joint before we go back to work.
Some of the bad rap cortisone therapy takes is actually because osteoarthritis is a progressive disease (either slowly or quickly depending on the cause). You can control the pain and short term progression of arthritis with cortisone, but as long your horse is working, the process will continue. It is our job as veterinarians is to slow the process down. There are some experiments being conducted to try and find a prevention for it. Wouldn’t that be great!
Other treatments we recommend to reduce the pain of joint disease include surgical correction if indicated, rest, cold/hot therapy, acupuncture, support wraps, cold laser, Adequan injections, Legend injections, NSAID administration and oral supplements of glucosamine, chondroitin and MSM. Hopefully now you know you don’t have to be nervous about considering joint injections as well.
Please don’t hesitate to call and talk to one of our veterinarians about the options for your horse.
Video: This horse has a lot of joint fluid pressure due to inflammation, which is seen when the needle is initially inserted into the joint and the viscous fluid drips out (it sometimes will come out in a steady stream!). Once some of the pressure and fluid is expelled, the cortisone +/- hyaluaronic acid is injected into the joint space.