What are they?
Joint injections are used to relieve pain and inflammation within the joint. For the most part, they are composed of a corticosteroid and hyaluronic acid. The corticosteroid acts by decreasing the inflammation and pain associated with it. The hyaluronic acid works by lubricating the joint and thereby decreasing the level of inflammation. Hyaluronic acid is the main component of joint fluid and acts as a viscous lubricant. When a joint becomes inflamed, the fluid degrades and the level of viscosity and lubrication within the joint decreases leading to more inflammation. Therefore, the reason hyaluronic acid is injected with the steroid is to help replace what has been lost or degraded.
Conventional joint injections are the most effective and most affordable option however biologiques are another very good option.
Biologics such as Irap or PRP are also used as joint injections. Irap (interleukin 1 receptor antagonist protein) is used to decrease inflammation within the joint but is much more expensive than conventional joint injections. PRP (platelet rich protein) is also used but to a lesser extent than conventional injections and Irap injections. It seems to be less effective as a joint injections as opposed to its very popular use in soft tissue injury healing. Both are created by drawing blood from your horse that undergoes processing which isolates certain antiinflammatory components to be reinjected in the joint(s) of interest.
Are they bad?
When people are told by their vet that injections are recommended either they do it or they are afraid to do it and in my experience in both cases its because they care for their horse.
The most common fears I hear from clients who are resistant to the idea is that they have heard that injections are bad for the long term health of the joint and that if you do it once you have to keep doing it. The thing is, if your horse truly has a sustained amount of inflammation in his or her joint that goes untreated, there are definitely going to be long term consequences in not only the health of the joint but in his or her overall health. Sustained inflammation leads to joint damage and even arthritis not to mention added stress on the rest of the body due to compensation for lameness. In fact I have many patients that have had their joint(s) previously injected either by me or another veterinarian in the past that do not require regular injections. Of the horses that do require a regular injections, I don't necessarily see the frequency increase over time. I think a couple reasons horses are being injected more today than maybe in years past are differences in genetics, training age, human perspective and level of performance.
As a veterinarian, my concerns with joint injections are making sure they are truly needed and making clients aware of the possible immediate risks of injections. In rare instances horses can have a reaction to the material being injected or can develop infection in the joint, all of which happen within days of injection and can be life threatening. Luckily this is a very rare occurrence in practice and I'm very fortunate to not have experienced it first hand.
Are they right for my horse?
I know this is a question that many horse owners struggle with when trying to balance performance and comfort of their horse with long term health and financial concerns. So, how do you know if injections should be considered for your horse: listen to your vet and your horse. Many horse owners will notice that their horse just isn't performing quite right and that something has changed either gradually or acutely such as not wanting to use their hind end as well, maybe feeling feeling a bit off or short strided in one or more limbs, maybe a bit sore in the lower back, etc. Its usually something along those lines that gets the owner to call the vet and have an exam. Once a veterinarian has done a thorough moving exam and likely some imaging such as radiographs he or she then provides recommendations. Some of the things your vet may notice that would indicate or warrant joint injections could be:
Gait symmetry or lameness that can range from quite mild to severe (an irregularity or unevenness in gait in the hind or front end or both depending on the limb or limbs affected)
Positive response to flexions corresponding to the joint in question (their gait will become more uneven and/or lameness will become more evident when that joint is flexed)
Joint effusion may or may not be noted upon examination (this can be seen visually in some joints and palpated indication there is inflammation in the given joint(s))
Nerve and or joint blocks resulting in resolution of lameness or positive flexion (your vet will inject a numbing agent similar to lidocaine into the nerve or associated joint to help more specifically isolate the area the lameness is coming from to better guide what should be imaged and what possible treatments such as injections are indicated)
Imaging such as radiographs that show irregularities in the affected joint(s)
After having listened to the history my client has provided, taking in all my observations during the examination and performing any diagnostics that are indicated to isolate the source...I then provide my recommendations. More often than not, my recommendations will come along with shoeing/trimming recommendations to help with whatever issue has been diagnosed. More often than not, the need for injections is a side effect of imperfect conformation, imbalances in the foot, wrong shoe type, etc. all of which can generally be aided with some podiatry changes if necessary for a more holistic approach that may save you from having to have your horse injected as often (or at all). Alternative therapies such as IV or IM injectables (such as legend or adequan), acupuncture or shockwave therapy can be very effective either in place of injections (in some cases) or in combination for a more “whole horse” approach.