Here is  part 2 of our summary of the orthobiologic options currently used to manage equine osteoarthritis, drawing directly from current veterinary publications.   Platelet-rich plasma (PRP) therapy has become a popular biologic treatment for equine lameness because it uses the horse’s own blood to promote tissue healing rather than just mask pain.

PRP is created by centrifuging whole blood to concentrate platelets, which release essential growth factors that regulate wound healing and synergistically regulate cell proliferation, angiogenesis, cell proliferation and collagen production.   When injected into injured tendons, ligaments, joints, or muscle, PRP aims to enhance the body’s natural repair processes, often used soft tissue injuries and early joint disease. In horses with lameness, PRP is often used as part of a multimodal rehabilitation program, with the goal of improving tissue quality, shortening recovery time, and reducing reinjury compared to rest and anti-inflammatory therapy alone.

Platelet-Rich Plasma (PRP) is plasma with concentrated platelets, containing growth factors that support tissue repair. There are two types  P-PRP (leukocyte-poor) and L-PRP (leukocyte-rich).  PRP releases growth factors (PDGF, IGF, TGF-β1, VEGF) that promote matrix synthesis, reduce inflammation, and support healing.  Increasing evidence supports PRP for equine OA, though optimal platelet/leukocyte concentrations remain unclear and studies are ongoing in addition to those that aim to determine the optimal number or concentration of platelets.  Human studies may suggest P-PRP may be superior for OA though patient variability and the nature of white blood cells in various types of injuries requires further study for standardized protocols to be established.  While PRP is autologous, safe, minimally invasive, results can vary between commercial kits and patients.  Additionally best practices suggest performing a CBC prior to PRP harvest and usage is warranted due to effects of white blood cells and individual variation with respect to patient inflammatory indices.

PRP is most commonly used for inflammatory and early degenerative joint conditions in horses—situations where the goal is to calm inflammation and support cartilage and soft-tissue healing rather than just relieve pain. Joint problems where PRP is frequently applied include:

• Low-motion joints (distal hock joints, coffin joints)
• High-motion joints (fetlock, carpus, stifle)
  
• PRP can reduce synovitis and may help slow cartilage breakdown when used early.
• Acute or chronic inflammation of the joint lining and capsule
  Common in performance horses after repetitive strain. Sacroiliac  joints in horses that cannot have corticosteroids due to metabolic and endocrine disorders
• Following surgical removal of osteochondral fragments
  PRP may improve cartilage repair and reduce post-operative inflammation.
• Stifle conditions with meniscal tears
• Intra-articular ligament strains (e.g., cruciate or collateral ligaments)
• Focal cartilage defects or subchondral bone injury
  Used as an adjunct to support healing.
• When lameness is driven by joint inflammation rather than purely bone pathology (navicular disease)
• Sprains or blunt trauma causing persistent joint effusion and pain

it is noteworthy that PRP has also shown promise in helping manage chronic endometritis in problem breeders

Got a question on a lameness problem affecting your horse?  We are here to help.

Chuck Maker DVM   Justine Stalnaker DVM