The use of intra-articular corticosteroids for traumatic arthritis and osteoarthritis (OA) is common in the horse. The beneficial and deleterious effects of the principal corticosteroids used betamethasone esters (Celestone [Soluspan], methylprednisolone acetate [Depo Medrol], and triamcinolone acetonide [TA] [Vetalog or Kenalog]) have been defined for the horse. While TA has both disease-modifying as well as symptom-modifying effects, methyl prednisolone acetate has deleterious effects on the articular cartilage. Studies in traumatically injured joints show the same rationale (suppression of deleterious mediators associated with inflammation) and positive results from the use of TA in both equine and human patients. Studies in the experimental equine OA model allow for more in-depth knowledge of disease-modifying effects. Recent insights allow us to understand posttraumatic OA as an early consequence of joint injury that may require a more aggressive and proactive treatment approach than commonly applied to date.