By William (Billy) Hodge, DVM

We ask a lot of our equine partners. Regardless of the discipline, maintaining optimal joint health is essential for any horse’s performance. Horses are athletes and lameness is one of the most common reasons for decreased performance. By addressing lameness issues as soon as they develop, the impact on the horse’s career can be minimized. Joint disease in horses is very common and as such, the use of one or several therapies can maximize soundness and improve long-term joint health. 

Injection therapies aid in reducing joint lameness by providing anti-inflammatory mechanisms. These products cannot prevent lameness but play a vital role in establishing a healthy joint after an injury, and therefore play a role in reducing lameness and fostering long-term soundness. This article aims to outline the most commonly used equine injection therapies in Canada.

It’s never welcome news to the horse owner, but joint disease is a common diagnosis when lameness develops. Fortunately, there are several therapies available to maximize soundness and improve long-term joint health. Photo: Shutterstock/Wallenrock

Legend^® is used in equine sports medicine and is widely available. It is currently made in an intravenous (IV) form and an intra-articular (IA, joint injection) form. Legend^® is a hyaluronate sodium (glucosaminoglycan, also called HA) that is present in synovial fluid (the fluid in the joint). One major function is the regulation of a normal joint environment; hence, it provides anti-inflammatory properties to the joint and also gives the joint fluid its viscosity (protects the joint). It is indicated (used) in the treatment of joint dysfunction of the carpus and fetlock due to osteoarthritis. It has not been approved for other joints but has shown to be effective for all joints (e.g., coffin, pastern, stifle). It is licensed for IV use weekly for three injections known as the loading dose.  Anecdotally, there has been the recommendation to use it monthly after the initial injection protocol.

Studies show that Legend^® decreases lameness and it has been widely accepted in the showing community to aid in reducing joint lameness (inflammation). It has been used by many veterinarians both by IV and IA. The IV form is for systemic use and the IA is for direct joint injections. It has been given in joints alone but is commonly given combined with a steroid for IA use. Used alone, it can cause “flares” in the joint or tendon sheath although this is not seen commonly.

Legend^® has been known to: 

• Decrease the degree of lameness;
• Decrease the inflammation in the joint;
• Decrease the inflammation in the joint lining;
• 90 percent of cases given IV injection and 96 percent given IA show improvement in lameness.

Similar products which fall into the same category as Legend^® include HY-50^®, Hylartil^®, and Map-5^®. These products are readily available and can be used in the same manner for IV or IA use in horses. They have individual successes in horses and therefore use may determine which product is right for your horse.

Joint injections of the hock and fetlock joints. Photos: Clix Photography (left); iStock/Groomee (right)

Related: Regenerative Medicine

Adequan^®, recently reintroduced to the Canadian market, is a polysulphonated glucosaminoglycan (PSGAG) recommended for the intramuscular (IM) treatment of degenerative/traumatic joint dysfunction associated with lameness of the carpus and hock (tarsus) joints. It is given IM every four days for seven injections. The main use is after joint surgery, but many horses are given this course without surgery as it has shown to reduce lameness and has anti-inflammatory properties. 

Adequan^® has been shown to:

• Reduce inflammation;
• Restore synovial joint lubrication;
• Repair joint cartilage;
• Reverse the disease cycle of osteoarthritis.

Adequan^® was historically also used in joint injections but has been linked to cases of sepsis (infection); therefore, when used for intra-articular injections it must be combined with antibiotics to reduce this risk. Anecdotally, it has been given monthly after the initial course for long term management.

Address lameness issues as soon as they develop, starting with a thorough examination by your veterinarian. Photo: iStock/Urbancow

Cartrophen Vet^® (pentosan polysulphate sodium or PPS) is recognized as another type of equine IM injection. It is a heparinoid that allows increased blood flow to the joint lining thereby making the joint less stiff, and it has shown to have anti-inflammatory properties providing improved joint function and health. A canine product, in my experience it has been widely used in horses for lower hock joint pain. The course is one injection every week (five to seven days) for four injections. Anecdotally, it has subsequently been used monthly. It has been shown to decrease lameness and improve overall joint health by treating acute and chronic osteoarthritis (degenerative joint disease).  

Cartophen Vet^® has been found to:

• Help cartilage production
• Improve synovial fluid quality
• Improve blood flow
• Anti-inflammatory effects
• Decrease/inhibit degeneration of the joint by harmful inflammatory mediators and enzymes

These products can be used in combination. Effectiveness will be different in each horse and therefore careful examination of the horse and a diagnosis will dictate which product may be most beneficial. At our veterinary clinic, we commonly use these products and find them to aid in our management of lameness caused by joint disease.

Related: Serviceably Sound Horse - What Does It Mean?

Related: Equine Lameness Evaluation

More by Dr. William Hodge

Main Photo: Healthy joints are essential for the performance of our equine athletes. Pictured are Rebecca Howard and Riddle Master at Rolex Kentucky 2011. Credit: Clix Photography