So what exactly are joint injections in horses?
JOINT INJECTIONS EXPLAINED FOR THE HORSE OWNER -
What are joint injections in horses? Should my horse be injected and at what age? How often should joint injections be performed? I heard joint injections are bad, is that true? My trainer said to have joints injected on my horse, is this needed?
These are common questions that come my way. There seems to be a lot of uncertainty and many different opinions, from different trainers, fellow riders at shows, other owners around the barn, and even between different veterinarians.
Joint injections are sometimes used for the treatment of lameness in horses, across many disciplines and types of horses. In spite of how common this procedure is, many owners still struggle knowing when or if this is needed for their horse. My goal is to help educate animal owners, in conjunction with the advice of your veterinarian, if joint injections are the right decision for treating lameness in your horse.
So here are some facts.
What are joint injections in horses?
Put simply, joint injections are a veterinary procedure that involves a medication administered directly into the joint of concern (rather than administered intravenous, intramuscular, or by mouth). By definition, joint injections are technically called “intra-articular injections”.
What medications are administered in joint injections?
Most medications that are administered into joints are anti-inflammatory in action. The most common group of drugs used is corticosteroids. Some popular formulations include triamcinolone, methylprednisolone, or betamethasone. Other more novel therapies are cell based, and include autologous conditioned serum (IRAP), autologous conditioned plasma (Prostride), platelet rich plasma, and bone marrow derived stem cells.
Sometimes, other medications that can be administered into the joint (often at the same time as corticosteroids) are joint supplements, like hyaluronic acid or Adequan (PSGAG). Antibiotics, when indicated for existing infection or as a precaution against infection, can also be injected.
When are joint injections needed? What are preventative joint injections?
First, the correct joint causing pain needs to be identified. Without a proper diagnosis, a joint injection may not be of any benefit in helping your horse. A proper diagnosis is best made by an equine veterinarian with a special interest in lameness.
As a rule, joint injections are only recommended when clinical lameness is present and the joint is inflamed (synovitis) or arthritic (osteoarthritis). “Preventative” joint injections are a concept advocated by some in the horse industry wherein normal joints are injected to “prevent” disease. This concept makes no sense and should not be a reason to have joint injections performed in your horse, especially if corticosteroids are being administered. Corticosteroids may be great at reducing inflammation in diseased joint, but in normal joints they promote cartilage erosion and degeneration, which can lead to osteoarthritis actually developing. That doesn’t sound preventative at all!
What are the benefits of joint injections?
The best benefit of joint injections — say in comparison to giving Bute (phenylbutazone) orally or intravenously — is that the therapy is extremely effective when given at the direct site of inflammation, the joint. Although corticosteroids may not be gentle against cartilage, they consistently and effectively resolve the inflammation present in the majority of cases.
The other advantage that corticosteriod joint injections provide is a reduction of inflammation for a prolonged amount of time (generally months versus days with other medications and routes). In fact, most horses that have osteoarthritis may only need to be treated 1 to 2 times per year to keep the horse performing well.
What diseases are treated with joint injections?
There are two main joint diseases that can cause uncomplicated lameness in the horse, and can be managed with joint injections. The first is “synovitis”, or simple joint capsule inflammation. This can develop secondary to repetitive accumulation of normal forces through the limb during exercise, or secondary to trauma or sprain.
The second is “osteoarthritis”. Osteoarthritis is a highly complicated disease that manifests as degeneration of the cartilage in the joint, and eventually results in degenerative changes to the joint capsule and subchondral bone. Although no cure for osteoarthritis exists yet (this is why total hip replacements are a thing in human medicine), the pain associated with osteoarthritis can be managed with joint injections.
A third, less common indication, is utilizing joint injections for treatment of infection in the joint. This can be seen in very young, sick foals or horses that develop joint infection secondary to a wound or laceration. Either antibiotics or sterile physiological solution can be injected / lavaged through the joint environment as treatment.
Do joint injections cure arthritis?
Unfortunately, no. Osteoarthritis is a very complicated disease. Once established, the cartilage begins to degenerate, leading to secondary changes in the joint capsule and subchondral bone. The imbalance present in degeneration versus restoration cannot be reversed — hence no cure. However, reducing the inflammation in the joint using various medications achieve two big goals: (a) the speed of which the degeneration occurs is reduced; and (b) the lameness is improved due to the decrease in inflammation (which causes joint pain).
However, if the joint is only inflamed (a term we call “synovitis”) without the degenerative osteoarthritic process present, then many horses can respond favorably to a joint injection. In some horses, they never need repeat future joint injections to be performed.
What are the risks of joint injections?
Although extremely uncommon, a complication that all owners should be aware of is the risk of secondary joint infection (bacteria get into the joint during the procedure). Overall, joint injections are considered very safe if your veterinarian follows some very specific standards of care. These are things that you can observe them performing, such as:
- Preparing the skin over the joint with disinfectant for a minimum of 10 minutes
- Using sterile, latex gloves
- Using a brand new bottle of medication for each horse
- Using brand new needles for each injection site
- Some veterinarians will even include antibiotics (like amikacin or gentamicin) in the joint injection as a precaution (though this isn’t 100% routine amongst veterinarians, and is personal preference).
However, even with all precautions performed, a joint injection can still develop. A recent retrospective out of Australia documented the risk of joint infection secondary to joint injection to be 13 infections in 16,624 injections. This amounts to a 0.078% risk. (Steel, 2013, Aust. Vet. J.)
Signs of joint infection include severe lameness, swelling and pain to palpation around the joint that was administered. If you notice these symptoms, consulting your veterinarian or an ACVS equine surgical specialist is recommended.
How often are joint injections needed?
This is really variable from horse to horse, joint to joint, and type of athletic discipline. Osteoarthritis can be mild, moderate or very severe which can play a large influence in frequency. Some owners compete all year round, whereas others only enjoy riding their horse during summer seasons. How hard the horse has to work is also a large influence — is the horse competing at very fast speeds and putting lots of forces through inflamed or diseased joints, like a barrel racer; or does the horse only need to walk and occasionally trot, as a causal trail riding horse.
When treating osteoarthritis, most horses respond for several months, upwards to years. As mentioned earlier, if the joint is only inflamed (synovitis) with no degenerative process present, then often only one joint injection may be needed. Continually assessing how your horse is performing, and having your veterinarian perform regular lameness examinations every 3 to 6 months will best help you determine if joint inflammation has returned following previous joint injections.
We hope this short summary on joint injections provides you value. Do you have further questions or experiences regarding joint therapy or other lameness topics you are curious to learn about? Feel free to respond below, or message Dr. Tatarniuk on facebook with specific questions.
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