Osteoarthritis in the Equine Athlete

Osteoarthritis (OA) is the most common cause of lameness in horses with some studies attributing up to 60% of all unsoundness in the equine athlete to this process. While for some this degenerative disease is career ending, plenty more are maintained with early signs while continuing to lead active lives.

 The causes of osteoarthritis are varied, but in all it results in a loss of integrity in the cartilage surface of articulating joints. This results in pain, inflammation and subsequent loss of function. In severe cases the bony surfaces of the joint are affected, leading to bony remodeling and ultimately fusion of the joint.

 While some horses are predisposed to osteoarthritis through genetic factors, the primary causes are trauma related, although the severity of this trauma can be relatively minor in relation to the impact on the joint.

 Common predisposing factors include:

  • Injury to the joint structures – microfractures of the bone, ligament damage
  • Infection of the joint – septic arthritis, synovitis, capsulitis
  • Age related degeneration
  • Micro abrasions due to daily wear and tear, especially in the horse exposed to work on hard ground or strenuous exercise, or simply the big moving horse
  • Osteochondrosis (OCD)

 Your treatment options once your horse has been diagnosed with OA are many and need to be discussed with your vet to find a plan that suits you, your horse, your expected outcomes and your wallet.

1. Pain management with Non-Steroidal Anti-Inflammatory Drugs (NSAID’s) e.g. Phenylbutazone (Bute)

Although NSAID’s are a long-term solution given to many, these need to be approached with caution. They certainly have their place in the acute setting, providing immediate relief from symptoms and reducing the inflammation rapidly, therefore preventing further damage. However long-term the side effects of these drugs can be devastating and ultimately more grim than the disease process they are treating, with life-threatening complications such as gastric ulcers, kidney impairment and diarrhoea. NSAID’s are also banned substances and cannot be used on the competing horse.

2. Intra-articular injections

There are many options for intra-articular injections including hyularonic acid, polysulfated glycosaminoglycans (GAG’s) and corticosteroids. Once again these can provide immediate relief by reducing inflammation and introducing fluid volume into the joint space. There are side effects to consider – there is always a danger with injections and the trauma caused by the introduction of a needle itself can produce further negative impacts on the cartilage surface you are trying to protect. The after care is also extremely important, usually including several days box rest which is labour intensive and means time off work for the horse.

 3. Intramuscular polysulfated glycosaminoglycans (GAG’s)

There is less impact to the joint with these injections and side effects are usually restricted to localised swelling and pain at the injection site, however the effects are also subsequently reduced with the medication needing to be metabolised systemically.

4. Weight Management

It goes without saying that a lighter horse will produced a lighter impact on the joints with every step. Excess weight is a key component in many causes of soundness problems, not just osteoarthritis, and therefore should be part of the management of any equine athlete. Talk to your vet or your equine nutritionist (nearly every large feed company provides this service free of charge on request) about a suitable diet for your horse, taking into account their energy and performance requirements and your expectations as a rider. Don’t let your vanity get in the way of the health of your horse – there are many competitors out there compromising their partners longevity, particularly in showing, dressage and children’s ponies.

5. Physical Therapy

The use of non or reduced weight bearing activities during rehabilitation can help keep the horse fit and joints mobile while recovering. Consider swimming and the use of water treadmills, although do talk to your vet first as these can cause increased stress on connective tissues. You don’t want to replace one lameness with another! And be careful on return to normal work to increase the impact related activities slowly.

6. Supplementation

A balanced Omega fatty acid should be added to the horses diet. Make sure that the oil you choose balances the Omega-3’s and Omega-6’s to ensure the correct inflammatory response.