A head-to-head comparison of the corticosteroid triamcinolone and a combination of triamcinolone and hyaluronic acid (a natural articular cartilage and synovial fluid component) for horses with osteoarthritis yielded “unexpected” results, a group of Dutch researchers recently revealed.

“Veterinarians have been injecting arthritic horse joints with steroids either with or without hyaluronic acid for decades,” explained Janny C. de Grauw, DVM, PhD, from the Utrecht University Faculty of Veterinary Medicine in The Netherlands. “Many of those practitioners are under the impression that hyaluronic acid can minimize potential negative effects of steroids and that the combination provides more effective alleviation of lameness than steroids alone."

Despite the combination triamcinolone and hyaluronic acid’s popularity, there is little data to support it. To that end, De Grauw and colleagues recruited 80 client-owned horses with clinical joint disease, meaning they had a lameness of at least grade 2 on a 0 to 5 scale. All included horses had been diagnosed with a lameness of one joint in one limb. The researchers assessed horses’ lameness and effusion (swelling) scores at the start of the study, just before the joint was injected, and again three weeks after injection.

The researchers randomly assigned study horses to one of two treatment groups that received either 12 mg of triamcinolone or 12 mg of triamcinolone and 20 mg of a high molecular weight hyaluronic acid. Horses received a single injection and were walkedfor the first three weeks of the study