Osteoarthritis (OA) is the most common joint problem in horses, causing over 60% of all equine lameness cases. While common in senior horses—affecting over 50% of horses older than 15 and 80-90% over age 30—it can affect horses of any age, particularly those in athletic careers. It is similar to that in people where there  is no cure for this progressive, degenerative disease, Many new treatment approaches are available beyond the age old corticosteroid injections used commonly in the past. RF pastern showing moderate boney changes associated with osteoarthritis/high ringboneWith a recent paper presented on the elevation of a horse’s insulin following the use of intra articular corticosteroids and its potentiation of laminitis, we thought a weekly series on orthobiologics and other intra-articular therapies would help horse owners understand the novel approaches to managing osteoarthritis in horses. 

Orthobiologics in horses refers to a group of regenerative therapies derived from the horse’s own tissues or biologically active substances that are used to enhance healing of musculoskeletal injuries. These treatments aim to harness and amplify natural repair mechanisms rather than simply manage pain or inflammation. Common orthobiologic therapies include platelet-rich plasma (PRP), autologous conditioned serum (ACS), and stem cell–based products, which are increasingly used for tendon, ligament, and joint disease. As equine athletes are prone to repetitive strain and degenerative conditions, orthobiologics have become an important tool in modern equine sports medicine, offering the potential for improved tissue quality, reduced reinjury rates, and more sustainable long-term outcomes. IRAP collection syringe with etched glass beeds

We’ll discuss IRAP in this first installment of our 6 part blog on joint therapies. Autologous Conditioned Serum (ACS) or IRAP  (I wrap) as it is called in the industry,  stands for Interleukin Receptor Antagonist Protein.  It begins with a 60 cc sterile blood draw from the horse which is incubated causing the horse’s monocytes, (a type of white blood cell) to produce anti‑inflammatory cytokines (notably IL‑1Ra).  Interleukin (IL) 1 receptor antagonist protein is just that.  It is a protein that blocks or downregulates  deleterious interleukins (IL‑1β) and catabolic metaloprotein enzyme (MMP) expression in joint tissues,  thereby limiting inflammation and further joint damage and degradation.  Harnessing the body’s own messaging system and blocking multiple steps of the inflammatory cascade within injured joints it is an effective means of managing early to moderate synovitis and the furtherance of osteoarthritis by slowing the degradation of cartilage.Joint anatomy with cartilage in blue surrounded by amber joint fluid and synvial/joint capsule

IRAP offers a strong anti‑inflammatory profile and has a low risk of joint flare due to its acellular nature and the ability to have sufficient product to inject multiple joints off one blood draw.  It does have the drawback in that it does require approximately 22-24 hours incubation prior to injection.

IRAP, one of several orthobiologic therapies available today are increasingly favored over corticosteroids due to safety concerns and the desire for more disease‑modifying effects rather than simply masking the pain associated with osteoarthritis.preparing the coffin joint for injection at Alpine Equine