Managing Osteoarthritis in Horses: Combining Platelet-Rich Plasma with Corticosteroids

Combining the corticosteroid triamcinolone (TA) with platelet-rich plasma (PRP) to treat synovitis or osteoarthritis in athletic horses appears beneficial. A combination of TA and PRP improved clinical signs of osteoarthritis in one study, providing better long-term joint comfort than TA alone.^*

Synovitis and osteoarthritis occur frequently in athletic horses, particularly in the fetlock joint, limiting a horse’s athletic career. Corticosteroids such as TA are a mainstay of osteoarthritis therapy because they provide short-term symptomatic relief by improving joint mobility and reducing lameness and joint swelling. Unfortunately, intra-articular steroids are known to have detrimental effects on the articular cartilage lining the ends of the bones inside joints.

Unlike TA, PRP has no known adverse effects on cartilage. Instead, PRP contains growth factors that stimulate tissue regeneration. Evidence also supports analgesic and anti-inflammatory properties of PRP in the osteoarthritis setting.

“Because of the potential negative effects of TA on articular cartilage, veterinary researchers recently proposed using a combination of TA and PRP in horses with osteoarthritis,” explained Catherine Whitehouse, M.S., a Kentucky Equine Research advisor. “More specifically, they hypothesized that a combination of TA and PRP would improve clinical signs of fetlock osteoarthritis longer than a single TA injection.”

Horses stabled at the Jockey Club of Turkey with fetlock joint effusion, pain on flexion of the fetlock joint, lameness localized to the fetlock, and/or radiographic evidence of osteoarthritis in the fetlock joint were included. Lameness was graded using a 0 to 5 modified AAEP lameness scale. Horses were divided randomly into two groups. All horses received a single 4 mg injection of TA in the affected joint(s). Horses in the TA+PRP group received a single 1 mL injection of one million platelets/ìL one week after the TA injection. Follow-up clinical examinations (lameness and flexion) were performed one and two weeks after TA in both groups and again two weeks after PRP in the TA+PRP group.

Thirty-two horses were included in the study. Thirty-one joints in 18 horses were treated with TA alone, and 21 joints in 14 horses were treated with TA+PRP.

Key findings included:

• Effusion scores were lower following treatment in both groups at all time points;
• Passive flexion scores improved in both groups following treatment, but a more significant improvement was noted in the horses treated with TA+PRP;
• Lameness significantly decreased in the TA+PRP group two weeks after TA and two weeks after PRP compared to baseline lameness scores; and
• Time until the horse re-presented to the Jockey Club Hospital for fetlock lameness was a median of four weeks for horses treated with TA and a median of seven weeks in horses treated with TA+PRP.

“A combination of intra-articular TA and PRP appears to be a promising strategy for managing osteoarthritis of the fetlock joint in athletic horses,” said Whitehouse.

The research team suggested that multiple PRP injections might have additional benefits, potentially leading to a better outcome than only the single injection used in the current study. Additional studies are needed, and comparisons to intra-articular PRP alone would also be valuable.

As part of a multimodal treatment approach to osteoarthritis, owners of athletic horses are encouraged to use oral joint health supplements as well.

“Because of the widespread availability of poor-quality nutritional supplements, be certain to select products with science-backed ingredients, including Kentucky Equine Research’s products containing sodium hyaluronate and long-chain omega-3 fatty acids that help support joint health and function,” advised Whitehouse.

Kentucky Equine Research also offers joint health supplements with glucosamine and chondroitin sulfate, each proven to slow the onset of osteoarthritis when used prophylactically.

^*Guidoni, K., E. Chiaradia, M. Pepe, A. Di Meo, A. Tognoloni, M. Seccaroni, and F. Beccati. 2024. The combined use of triamcinolone and platelet-rich plasma in equine metacarpophalangeal joint osteoarthritis treatments: An in vivo and in vitro study. Animals (Basel) 14(24):3645.