Systemic and Intra-Articular Therapies for Lame Horses

hock joint injection
IA therapy for horse
Intra-articular therapies for horses with joint disease include hyaluronic acid, Adequan (off label), polyglcan, polyacrylamide, corticosteroids, alpha-2 macroglobulin (A2M), and stanozolol. Amy Dragoo

Regardless of what medications, supplements, or combination of IA or systemic therapies you select for treating equine joints and joint disease(s), experts recommend slowing your own step first. 

“You need a diagnosis before you can treat! Don’t just dive in and start administering one of everything. Know the history, consider if you are a first or second opinion (i.e., What has already been done to this horse?), and perform necessary diagnostics and imaging to create an appropriate treatment plan,” recommended Tiffany Marr, DVM, from Miller & Associates in Brewster, New York. 

She added, “You need to take a whole-horse approach with a full physical exam before even jogging them out and watching them go under saddle. Importantly, you need to ask yourself, is it a poorly performing horse or a lame horse?”

Marr, together with Tim Ober, DVM, from John R. Steele & Associates, Inc., moderated the Table Topic Session Current Joint Therapies at the 2022 AAEP Convention in San Antonio, Texas. 

Marr and Ober opened the packed, evergreen session by helping attendees curate the following list of products/medications available for treating equine joints:

  1. Systemic products, administered IV or IM; 
  2. Nonregenerative intra-articular (IA) therapies; 
  3. Oral supplements and medications;
  4. Manual therapies;
  5. Topicals; and
  6. Regenerative therapies.

Although time constraints limited a full exploration of each of these topics, here’s what practitioners discussed for the first three topics:  

Systemic Treatments for Equine Joints

Adequan and Legend were the most popular injectable joint products used by attendees based on a quick survey of hands. Polyglycan was mentioned as an alternative, which Marr said she uses IV, not IA.

Whether there was enough science supporting the use of polyglycan, either IV or IA, was questioned. Marr and Ober both suggested that research from Colorado State was quite promising for IA use. However, Ober added that the data for IV use is not good enough to recommend it.

One attendee stated that polyglycan should be “used at your own risk.” 

The IM product sodium pentosan (pentosan polysulfate, PPS) can also be used. Attendees felt that the mild heparin-like activity was not a clinical concern. In fact, the heparin-like activity can be of benefit in support of circulation in some cases, suggested Ober. 

Attendees did not make any comments or suggestions regarding injectable chondroitin sulfate products. The moderators suggested that this could potentially reflect a lack of science supporting these products, making practitioners hesitant to reach for them. 

In terms of bisphosphonates, Ober said these products are being used off-label as a joint therapy in practice, presumably targeting subchondral bone and joint pain. 

“My practice has moved away from this drug class. We are worried about waking up the kidneys or delaying healing,” relayed Obel. 

Oral Nutritional Supplements

Products falling into this category listed verbally by practitioners during the session included hyaluronic acid, glucosamine, avocado-soybean unsaponifiables (ASU) and chondroitin sulfate. 

Given the proven disparity in product quality among oral joint health supplements and lack of definitive proof of efficacy, Marr asked attendees, “What do you say when a client says, ‘What supplement do you recommend?’”

Many practitioners responded with an emphatic no, saying they do not make specific recommendations. 

Marr and Ober both commented that it would be important to have a comfort level with the manufacturing process, ingredients, quality control of the manufacturer, and purpose of the supplement before making a specific recommendation. 

One attendee specifically mentioned that owners are faithfully using resveratrol, but they felt there was little science supporting this product. Another audience member relayed that resveratrol reportedly has disease-modifying effects and that an improvement in hock lameness was appreciated. The paper he cited was published by Watts et al. (2016) in the Journal of the American Medical Association

Nonregenerative IA Therapies

Products included by practitioners in this category were hyaluronic acid, Adequan, polyglcan, polyacrylamide, corticosteroids, alpha-2 macroglobulin (A2M), and stanozolol.

“Adequan got a bad rap when it first came out and never got over it. It is now a somewhat underutilized therapy in my opinion, and all IA use is off label. In my experience, we didn’t get any more flares with Adequan than other IA modalities,” relayed Ober. 

As a word of caution, Ober reminded practitioners that the multidose vial of Adequan should never be used in a joint because of the preservative it contains! 

“That is an important difference between the two Adequan products available on the market,” Obel relayed. 

Polyacrylamide was a hot topic in the session. The audience was split 50/50 regarding their choice between the two major brands. 

Marr and Ober remarked that while Arthramid and Noltrex are comprised of the same molecule as the primary ingredient and used as “lubricating agents,” the products are actually quite different. 

Some practitioners indicated they have had reactions or flares to one product but not the other. This has swayed their clinical choice. No post-injection infections were reported.

IA Steroids and Antibiotics

Turning away from the new toy and revisiting the tried and true, Ober asked attendees if they were still comfortable using corticosteroids and antibiotics in joints. 

“I never inject anything without a steroid,” said one conference attendee. 

But antibiotics appeared to be falling by the wayside, although they are still being used.

In defense of antibiotic use, one practitioner pointed out, “We aren’t working in sterile conditions. There’s the dog running around, people walking past with wheel barrels of hay, and I’ve even had to ask owners to not groom their horse at the same time I’m injecting. The conditions are often far from ideal.”

Marr pointed out that regardless of the evidence and each individual practitioner’s clinical impression, product selection for managing joint disease and discomfort is often client-driven. 

Consider Concurrent NSAID Use

As a final note, Marr and Obel recommended taking nonsteroidal anti-inflammatory drug (NSAID) use into consideration when selecting any of the above-mentioned products, especially bisphosphonates. 

“Even the COX-2 NSAIDs are not renal sparing! You need to keep tabs on renal function in any horse being administered an NSAID. This can be challenging nowadays because we as veterinarians have somewhat lost the control over NSAIDs. Owners can order their own NSAIDs online and don’t even consider them drugs. They treat Equioxx, for example, like a vitamin.”

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