Veterinarians have a wide range of options for treating equine joint disease. | Photos.comVeterinarians have a wide range of options for treating equine joint disease and often utilize a multimodal approach to include a variety of therapies. Some of the most common intra-articular (IA, into the joint) therapies veterinarians use include corticosteroids, orthobiologics, and polyacrylamide hydrogels.Steroids vs. Orthobiologics for Equine Joint DiseaseIn recent years veterinarians report using orthobiologics more frequently when treating horses with joint problems, said Erin Contino, MS, DVM, Dipl. ACVSMR, an associate professor at Colorado State University, during her presentation at the 2025 American Association of Equine Practitioners Convention, held Dec. 6-10 in Denver, Colorado. This is due to their long-term efficacy, overall safety, and in some cases client request.When using corticosteroids, veterinarians often turn to triamcinolone for high-motion joints such as the coffin and stifle joint and methylprednisolone for low-motion joints such as the pastern and distal (lower) hock joint. However, researchers have found some corticosteroids can be damaging to joints.Each has their own place, said Contino. Case selection is very important. She added that orthobiologics are often a better option for overweight and metabolic horses due to the potential endocrine effects of corticosteroids. In one study of normal horses, researchers found joint injections using triamcinolone led to a significant increase in the horses systemic insulin levels for up to 120 hours following injection. There is no safe dose of corticosteroids in metabolic horses, said Contino. We also cant rely on the horses appearance to determine his metabolic status, so testing is crucial.What Orthobiologics Do Veterinarians Use in Horses?Contino said the five types of orthobiologics veterinarians most commonly use are:Autologous conditioned serum (ACS), which blocks interleukin-1 beta (IL-1, a highly potent inducer of cartilage degradation in horses with osteoarthritis) and reduces inflammation. However, because it takes 24 hours to process before administration, veterinarians cannot complete the treatment in the same day. Researchers are currently looking for an off-the-shelf product to improve accessibility, said Contino.Autologous protein solution (APS) contains a large profile of cytokines (immunoregulatory proteins) in the joint that reduce inflammation and provide restorative factors. Contino said in one study horses showed a decrease in lameness following treatment with APS, and in another the joint tissue histopathology (cell structure when viewed under a microscope) scores improved after treatment.Platelet-rich plasma (PRP) utilizes beneficial growth factors of platelets to help repair joint tissue. Contino said veterinarians should be aware there can be substantial differences in the composition, including the concentration of platelets, in each individual PRP product. In a review of PRP use in horses, researchers found intra-articular PRP is likely effective, but there are a limited number of randomized control studies.Alpha-2 macroglobulin (A2M) is an acute-phase protein present primarily in plasma. In rats, A2M has shown to be chondroprotective (joint-protecting), and in humans it inhibits catabolic factors, said Contino, which refers to the destruction of cartilage. There is little research on its efficacy in horses, but one study showed it does not produce adverse reactions.Mesenchymal stromal cells (MSCs) have the strongest evidence for use in soft tissues but also can be beneficial in joints, said Contino, and have anti-inflammatory and immunomodulatory properties to optimize healing. In a study of goats with severe meniscal injury, the treated joints had repair tissue present after MSC injection. In another study researchers reported 75% of horses treated with MSCs following stifle surgery returned to work. One group of researchers found a decreased risk of superficial digital flexor tendon reinjury following MSC treatment.Polyacrylamide Hydrogel Treatment in HorsesCurrently, two injectable polyacrylamide hydrogel (PAAG) options are available on the marketa 2.5% product and a 4% producteach with different mechanisms of action, said Contino. The 2.5% integrates into synovial (joint) lining and creates synovial hyperplasia (an increase in synovial cells) for at least two years. It has also been shown to increase joint capsule elasticity.In clinical trial groups of 1242 horses treated with 2.5% PAAG, 6775% of the horses were still sound six months after treatment. In one study researchers saw soundness in 83% of horses two years after treatment. Small studies have shown better outcomes following treatment with 2.5% PAAG compared to corticosteroid treatment.Contino said 4% PAAG adheres to cartilage surfaces for at least one month and decreases friction. Researchers have found the product remains on the joint surface, but it does not appear to permanently incorporate into the joint. When compared to corticosteroids, horses treated with 4% PAAG showed decreased lameness, said Contino. In another study researchers found serial 4% PAAG injections were not detrimental.Take-Home MessageChoosing between corticosteroids, orthobiologics, or polyacrylamide hydrogels for equine joint injections depends on the individual horse, the joint involved, and underlying risks. Therefore, careful case selection supports long-term joint health and soundness, said Contino.