Equine Lameness Series: All About Joint Injections

Intra-articular injections, more commonly referred to as joint injections, are one of the most commonly performed procedures on equine athletes. In years past, joint injections received a bad reputation. This was largely a result of misuse and using lower quality medications in the injections, which gave subpar results. Research has proven that joint injections, if done appropriately, are a benefit to the equine athlete and can actually help to heal the joint rather than tear down the cartilage.

Joints are most commonly injected with a combination of hyaluronic acid (HA), a corticosteroid, and a small amount of antibiotic. However, there are different levels of injections that are available to tailor to each horse’s discipline and each owner’s budget.

• Corticosteroid: Using steroid alone is the simplest level of joint injection offered. This helps to quiet down inflammation within the joint and increase comfort for the horse. Peak effect is typically achieved around 10 days post-injection.

• Hyaluronic acid: Adding HA to a steroid injection is the next step up. In healthy joints, HA acts as lubricating molecules that promote smooth, frictionless motion. It also helps mitigate the action of inflammatory mediators within the joint and protects joint cartilage from degeneration. There are also different classes of HA, and at SPVS we use the highest quality with the highest molecular weight. This is important as the higher molecular weight products don’t diffuse across the joint capsule as easily as lower molecular weight products. This means the HA molecules keep the steroid centralized within the joint longer, which in turn enhances the healing process.

• Antibiotic: All our joint injections include a small amount of an antibiotic to help minimize any joint infection.

• Biologics: These are the current “gold standard” of joint injections. For biologics, we extract living organisms from the horse’s own blood and inject them directly back into the joint. By putting the horse’s own healing factors back into the joint, we are achieving an amplified healing effect. There are many biologic products on the market, including Prostride, IRAP, PRP, RenoVo, and more. At SPVS we are now offering Prostride!

Before we are able to inject joints, we need to determine which joints require treatment. This starts with our comprehensive lameness exam, as we discussed in our previous blog post. If more localization of the lameness is needed after the exam, we can narrow it down further with nerve blocks. With nerve blocks we can numb areas of the limb in a stepwise fashion to see if the horse becomes sound again. We can also try to localize the source of the lameness with diagnostics such as radiographs or ultrasound. Once we have identified the source and determined whether the issue would benefit from injections we can proceed with treatment.

Because we are entering into a joint when performing injections, a sterile prep of the site is absolutely necessary to minimize risk of infection. We also use a small amount of antibiotic in our joint injections to help minimize infection. Using antibiotic in joint injections has been a debated topic among equine veterinarians in the past, as it has been shown to have some negative effect on cartilage. However, many veterinarians believe that the benefit of protecting against joint infection outweighs the risk, especially if using very small amounts like we do.

After joint injections, we prefer the patient to rest for at least 3 days, but 5-7 days is most ideal. Then they may return to work. We recommend doing a follow-up lameness exam 4-6 weeks after injections to monitor response to treatment and make sure the patient is 100% sound. Occasionally we find that the injections treated a large source of discomfort and once that is treated there is another issue that was being masked by the joint pain. At SPVS, we offer our follow-up lameness exams for free after performing joint injections.

Interested in learning more? Follow along in future newsletters for our continuing series on equine lameness!

The article “Equine Lameness Series: All About Joint Injections” first appeared in our Summer 2023 Newsletter.

The Importance of Equine Lameness Exams

If you follow any equine-related accounts or groups on social media, you likely have seen the post about how flexions during lameness exams are causing pain and injury to your horse. The typical accompanying image on that post compares flexing a horse’s front limb to a person’s arm being twisted behind their back. This is an inaccurate comparison because during a flexion test you are flexing the horse’s limb in its normal alignment, while twisting someone’s arm behind their back is bending it in an abnormal alignment. Posts like this make us realize how little some people understand the “why” behind comprehensive lameness exams. Since we are passionate about equine sports medicine and are committed to performing high quality lameness exams and therapies, it’s important to us that equine owners understand what we are doing.

Janelle spent a large part of her vet tech career working on the top performance horses in Colorado and beyond during her time at Countryside Veterinary Hospital in Colorado. Thanks to Janelle’s connections, Dr. Kolar was able to do lameness training with Dr. Shoemaker at Countryside as well and hone her skills. At South Peak Veterinary Services, we perform a full lameness exam every time we are seeing a new patient for lameness or a new issue.

A thorough lameness exam consists of the following:

• Gathering a thorough medical history on the horse

• Evaluation of the horse at rest and in motion. We evaluate the horse at a walk, trot, and lunging in a circle in both directions. If conditions allow, we also prefer to evaluate the horse moving on firm and soft ground for comparison. This gives us a baseline to compare our flexions to.

• Thorough hands-on exam. We palpate along the entire spine, each limb, and major muscle groups to identify areas of sensitivity and any abnormalities

• Hoof testers. Hoof testers are applied to every foot to look for sensitivity

• Flexions. We generally flex the carpus and fetlock on both front limbs, and the stifle, hock, and fetlock on both hind limbs. There are additional flexions we can perform if we feel they are necessary, but they aren’t part of our routine flexions. The purpose of flexions is to place mild strain on specific areas of the limb to try to identify the source of the horse’s pain. The limb is held in a flexed position for a recommended length of time, then the horse is jogged off in a straight line. If the horse appears lame in the first few steps but then is sound, we would not call that a positive response. We expect the horse to take a couple bad steps as they readjust, just as if a person held their leg flexed at the knee for a period of time and then tried to jog. However, if the horse appears lame the entire length of the trot then we would call that a positive response. During flexions, we are not bending the horse’s leg in a way that is abnormal to them, so it is not comparable to twisting someone’s arm behind their back. We are placing mild strain on a specific area of the limb, but not enough to cause injury.

After a thorough lameness exam, depending on results, a patient can either receive treatment or may require additional diagnostics to isolate the cause of the lameness.

Lameness exams are a vital component of any performance horse’s care. Providing a thorough exam every time is critical to ensure that horse is receiving the best care and can return to work. Since equine lameness is a favorite topic of ours, we plan to put out more educational content! Keep an eye out for more information on our social media and in our future newsletters!

The article “The Importance of Equine Lameness Exams” first appeared in our Spring 2023 Newsletter.