5 Intra-Articular Therapies Every Equine Vet Should Know for Osteoarthritis Management

Osteoarthritis (OA) remains one of the leading causes of reduced performance, chronic lameness, and early retirement in horses. While numerous intra-articular treatment options are available today, choosing the right therapy can be challenging. With no true disease-modifying osteoarthritis drug (DMOAD) currently available, most treatments focus on reducing inflammation, controlling pain, and preserving joint function¹. 

So which therapies deserve a place in your treatment arsenal? 

1. Intra-Articular Corticosteroids: Still the Clinical Workhorse 

Glucocorticosteroids remain among the most commonly used intra-articular treatments for equine OA. Their ability to suppress inflammation at multiple points in the inflammatory cascade often results in rapid improvement in lameness and joint comfort¹. 

Recent evidence suggests corticosteroids provide reliable short-term clinical benefits. However, practitioners should remain mindful of concerns regarding repeated administration and potential effects on cartilage health, particularly in heavily used athletic horses². 

Clinical Pearl 

For horses requiring rapid return to work, corticosteroids continue to offer one of the most predictable short-term responses. 

2. Hyaluronic Acid: A Popular Option with Mixed Evidence 

Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan responsible for the viscoelastic properties of synovial fluid and overall joint lubrication³. 

Although widely used, research findings remain inconsistent. Some studies demonstrate clinical improvement, while others show little advantage compared with placebo treatments¹. 

When to Consider HA 

• Mild to moderate synovitis 

• Early OA cases 

• Combination therapy with corticosteroids 

Clinical Reality 

Many practitioners report favourable results in selected cases, but current evidence does not consistently demonstrate superior outcomes. 

3. Platelet-Rich Plasma (PRP): Harnessing the Horse's Own Healing Potential 

PRP has become increasingly popular in sports medicine due to its concentration of platelets, growth factors, and anti-inflammatory mediators⁴. 

Most studies report improvements in lameness and clinical performance following intra-articular administration. However, the quality of evidence remains limited because many studies lack randomization, blinding, and placebo controls¹. 

Practical Limitation 

Not all PRP products are the same. Differences in preparation methods can result in substantial variation in platelet and leukocyte concentrations. 

Clinical Pearl 

When evaluating PRP studies, focus on the preparation protocol—not just the term "PRP." 

4. IRAP: Targeting Joint Inflammation at Its Source 

Interleukin-1 receptor antagonist protein (IRAP) therapy aims to counteract interleukin-1, a major inflammatory mediator implicated in OA progression¹. 

Several studies report positive clinical outcomes, particularly in horses with inflammatory joint disease. However, robust clinical evidence remains limited, and many published studies lack blinding or appropriate controls¹. 

Best Candidate Cases 

• Persistent synovitis 

• Performance horses requiring repeated joint management 

• Horses where corticosteroid use is undesirable 

Clinical Pearl 

IRAP may be particularly attractive when long-term inflammation control is the primary goal. 

5. Mesenchymal Stem Cells: The Most Promising Regenerative Option? 

Mesenchymal stem cells (MSCs) continue to generate significant interest because of their immunomodulatory and regenerative capabilities. These cells can be obtained from bone marrow, adipose tissue, umbilical cord tissue, and several other sources¹. 

Among available biologic therapies, MSCs currently have some of the strongest supporting evidence. Several studies evaluating stem cell therapy have incorporated randomization, blinding, and placebo controls while reporting positive clinical outcomes¹. 

What We Know 

• Improved clinical outcomes have been reported. 

• Safety profiles appear favourable. 

• Long-term disease-modifying effects remain unproven. 

Clinical Pearl 

Stem cell therapy may be best viewed as a promising management tool rather than a cure for OA. 

Choosing the Right Therapy: A Practical Approach 

What Practitioners Should Tell Owners 

One of the most important discussions with owners involves setting realistic expectations. Current therapies can improve comfort, reduce inflammation, and prolong athletic function, but none can reliably reverse established osteoarthritis. 

Successful OA management typically requires: 

• Weight and workload management 

• Regular monitoring 

• Appropriate rehabilitation 

• Strategic use of intra-articular therapies 

• Long-term client commitment 

Take-Home Message 

Despite the growing number of intra-articular treatment options available, evidence quality varies considerably. Corticosteroids remain the most established short-term option, while PRP, IRAP, and MSC therapies offer exciting possibilities but require further high-quality research. For practising veterinarians, treatment success continues to depend on careful case selection, objective monitoring, and realistic owner expectations rather than any single injection. 

References 

1. Nedergaard A, Carlsson LE, Lindegaard C. Evidence of the clinical effect of commonly used intra‐articular treatments of equine osteoarthritis. Equine Veterinary Education. 2024 Dec;36(12):646-58. 

2. Kolasinski SL, Neogi T, Hochberg MC, Oatis C, Guyatt G, Block J, Callahan L, Copenhaver C, Dodge C, Felson D, Gellar K. 2019 American College of Rheumatology/Arthritis Foundation guideline for the management of osteoarthritis of the hand, hip, and knee. Arthritis & rheumatology. 2020 Feb;72(2):220-33. https://doi.org/10.1002/art.41142  

3. Marinho A, Nunes C, Reis S. Hyaluronic acid: a key ingredient in the therapy of inflammation. Biomolecules. 2021 Oct 15;11(10):1518. https://www.mdpi.com/2218-273X/11/10/1518 

4. Brossi PM, Moreira JJ, Machado TS, Baccarin RY. Platelet-rich plasma in orthopedic therapy: a comparative systematic review of clinical and experimental data in equine and human musculoskeletal lesions. BMC veterinary research. 2015 Apr 22;11(1):98. https://link.springer.com/article/10.1186/s12917-015-0403-z