Joint wear and tear is a part of every equine athlete’s life. As your horse ages, joints naturally become stiff and sore – a process that is accelerated with heavy exercise.

Joint injections deliver medication directly to the affected joints. These injections are a reliable way to reduce pain and inflammation, supporting mobility and comfort in your horse.

Injections may be used to administer corticosteroids, hyaluronic acid, anti-inflammatory compounds, or platelet rich plasma. These treatments are most commonly used in horses with osteoarthritis, but may also be used to treat infections and other joint diseases.

While generally safe, there are some risks associated with injectable medications. These treatments can also be expensive and need to be repeated regularly to continue to work.

In addition to injectable therapies, there are many options to maintain joint health. Supplements, oral medications, exercise modifications, dietary strategies, topical treatments and bodywork are some of the modalities used to address joint issues in horses.

Consult with your veterinarian to determine whether joint injections are appropriate for your horse. Also, consider diet and management strategies to support your horse’s joint health and reduce reliance on pharmaceutical drugs.

Joint Injections for Horses

Most joint injections are administered intra-articularly, directly into the free space between the bones within the joint capsule.

There are three main reasons to perform intra-articular joint injections:

  • To block or anesthetize the joint in order to determine if a specific joint is the cause of your horse’s lameness
  • To sample lubricating fluid (or synovial fluid) in the joint and determine whether there is infection present
  • To introduce anti-inflammatory medications that reduce pain and increase range of motion

You and your veterinarian must take into account many considerations before deciding if joint injections are necessary for your horse. The type of injection used will depend on the intended purpose.

Joint Blocking

Anesthetizing or “blocking” the joint is a diagnostic tool used to identify where your horse’s pain originates from.

For example, let’s say you and your vet determine that your horse is lame in the hind end, but it is unclear whether the hock or the fetlock is the issue.

Your vet blocks the fetlock and asks to see your horse move again. If your horse is still lame, the source of the pain is not the fetlock. If your horse is now sound, the source of the pain is identified as the fetlock.

Synovial Fluid Sample

Synovial fluid is a clear, viscous liquid that provides lubrication and reduces friction in the joint.

If your horse is suffering from joint issues, your veterinarian may take a sample of the synovial fluid to determine the overall health of the joint. Your vet will examine:

  • Overall appearance of the fluid – the colour and thickness of the fluid can indicate infection or inflammation [1]
  • Protein concentration – too much protein can indicate infection or blood in the joint [1][2]
  • Nucleated cell count – an increase of cells with an obvious nucleus indicates infection [2]

Medicating the Joint

If your horse is experiencing soreness, intermittent lameness, or stiffness in a joint, your vet will likely suggest medicating their joint.

Before taking this step, your vet may perform flexion tests to determine which joints are causing pain. Your vet will hold your horse’s leg in a position that stresses one or multiple joints, then have the horse trot off in hand. This test allows the vet to see which joints become easily pained under stress.

Your vet may then take x-rays or perform an ultrasound on the suspected joint to visualize any arthritis or injury. Your vet may suggest medicating a joint if your horse is diagnosed with:

If you have a high-performance horse in heavy work, your vet may also suggest routine joint injections to maintain soundness.

Depending on how your horse reacts to treatment, your vet may suggest routine injections yearly, bi-yearly, or on an as-needed basis. It is not recommended to inject the same joint more than twice in one year. [3]