PgDip NAVP Bsc (Hons) Equine Physiotherapist
25/04/2025
A 2017 study found that racehorses receiving corticosteroid injections were FOUR TIMES more likely to suffer musculoskeletal injuries. These weren’t minor lamenesses, they led to long layups, early retirements, and in some cases, catastrophic breakdowns. That stopped me in my tracks. When we inject a horse to keep them “sound,” are we treating the injury, or are we simply hiding the pain?
Corticosteroids are powerful anti-inflammatories. They offer quick relief, especially for sore joints, but repeated use has a risky side. Over time, corticosteroids can accelerate cartilage breakdown and damage the very structures we’re trying to protect. That’s not just theory, it’s been proven in multiple studies. One 2022 review published in Equine Veterinary Education warned that long-term use of corticosteroids, even in low doses, can lead to irreversible joint degeneration.
And it’s not just steroids. Treatments like IRAP (interleukin-1 receptor antagonist protein) and PRP (platelet-rich plasma) are widely used, but the science behind them is still emerging. A recent meta-analysis found highly inconsistent outcomes with some horses showing improvement, and others none at all. These therapies show promise, but they are not miracle fixes. Their long-term benefits and risks remain unclear, especially when used repeatedly without a comprehensive rehab plan.
Even alternatives like Adequan and Polyglycan come with caveats. Adequan (polysulfated glycosaminoglycan) can help reduce inflammation and protect cartilage in the short term, but does not show lasting curative effects without rest or additional therapy. Polyglycan, often marketed as a joint lubricant, has been linked to increased bone proliferation and osteophyte formation. That means while it might make your horse feel better in the short term, it could be quietly encouraging abnormal bone growth that worsens arthritis and limits joint mobility over time.
It seems that most injections don’t fix the problem, they just silence the alarm bell. And when we quiet that bell without solving what caused it, we set the horse up for further breakdown. They keep working through masked pain, compensating, and eventually injuring something else. What seems like a solution quickly becomes a cycle of damage.
So, what does responsible use look like? It starts with intent. Injections should never be used as routine “maintenance” or as a preventative measure in otherwise healthy joints. There is no such thing as a preventative joint injection. Every time you inject a joint, you’re altering its natural chemistry and potentially weakening its future integrity. Instead, injections should be used after thorough diagnostics: imaging, flexions, lameness exams, and only as part of a comprehensive plan. That means rest. That means thoughtful rehab. That means time to retrain healthier movement patterns so the horse can come back stronger and more balanced, not just numbed. Injections can open a door to recovery, but they are not the recovery itself.
Responsible use also means reevaluating the workload. If a horse needs regular injections to keep doing the job, then maybe it’s the job that needs adjusting. I’m not saying injections are evil. They’ve done wonderful things for horses I’ve known and I’m not saying we should all stop injections forever. But if Beauty’s hocks need to be injected three times a year just to keep her jumping the 1.20s, maybe the 1.20s are no longer where she belongs. Maybe it's time to listen to what her body is telling us.
I’m not a vet. I don’t have a medical degree. I’m just someone who enjoys research and writing, and I would still argue that we need more research to ultimately determine what is "safe" for our horses. However, I do think it's important to be aware of what the science currently says, and having hard conversations about if the potential risk is worth the reward.
Your vet is your best friend in this process. Don’t change your horse’s care plan because someone on Facebook shared a study about joint injections being questionable…or because someone else said they’re harmless. Talk to your vet. Ask hard questions. Understand exactly what these drugs do, how long they last, and what they mean for your horse’s future soundness. Your vet knows your horse better than I ever could, and they want to help you make the best choices, not just the most convenient ones.
Studies used:
Johnson, B. J., et al. (2017). "Association between corticosteroid administration and musculoskeletal injury in Thoroughbred racehorses." Journal of the American Veterinary Medical Association, 250(3), 296–302.
Textor, J. A., & Tablin, F. (2012). "Platelet-rich plasma in equine musculoskeletal therapy." Canadian Veterinary Journal, 53(8), 841–849.
Frisbie, D. D., & McIlwraith, C. W. (2014). "Evaluation of autologous conditioned serum and platelet-rich plasma for treatment of musculoskeletal injuries in horses." Equine Veterinary Education, 26(12), 572–578.
McIlwraith, C. W., et al. (2012). "Effects of intra-articular administration of sodium hyaluronate and polysulfated glycosaminoglycan on osteoarthritis in horses." EquiManagement Clinical Research Reports.
Burba, D. J., et al. (2011). "Evaluation of pentosan polysulfate sodium in equine osteoarthritis." Equine Veterinary Journal, 43(5), 549–555.
Garbin, L. C., Lopez, C., & Carmona, J. U. (2021). A Critical Overview of the Use of Platelet-Rich Plasma in Equine Medicine Over the Last Decade. Frontiers in Veterinary Science, 8, 641818.
Boorman, S., McMaster, M. A., Groover, E., & Caldwell, F. (2022). Review of glucocorticoid therapy in horses: Intra-articular corticosteroids. Equine Veterinary Education, 35(6), 327–336.
Nedergaard, M. W., et al. (2024). Evidence of the clinical effect of commonly used intra-articular treatments of equine osteoarthritis. Equine Veterinary Education.
