Arthritis in Horses – Treating & Maintaining Healthy Joints

Updated March 29, 2024 | By: Andris J. Kaneps, DVM, PhD, DACVS, DACVSR

Equine Arthritis - Lost in Translation

You’ve noticed that your horse seems stiff, and you think the stiffness may be due to arthritis. You decide to do some research to see if your theory is correct. Some sources say it might be Degenerative Joint Disease (DJD), others suggest Osteoarthritis (OA), but all the signs sound the same. Confused? That's okay, you're in the right place — OA, DJD, and arthritis are just different names for a similar problem.

What is Arthritis in Horses?

Arthritis is a general term that refers to conditions that cause pain, stiffness, and swelling of joints that result in lameness. It is usually progressive and may result in permanent deterioration of joints.

Healthy joint (articular) cartilage provides a smooth, slippery surface that allows free movement and contributes to the shock-absorbing properties of the joint. Synovial fluid lubricates the joint capsule and contains components such as hyaluronic acid, which support and nourish the articular cartilage. As arthritis sets in, articular cartilage becomes irregular and damaged, which results in inflammation, stiffness, and discomfort.

Is Arthritis Common in Horses?

A study published in the Equine Veterinary Journal [4] identified arthritic changes in a herd of wild mustangs, which led the researchers to conclude that arthritis was a natural part of the aging process in horses. In essence, this means that arthritis is not only a problem for horses in heavy work, but that all horses are at risk for developing arthritis.

As even wild horses are affected, it’s no surprise that arthritis is one of the most common conditions in performance and pleasure horses. In fact, arthritis is believed to be responsible for up to 60% of all lameness [16]. Fifty percent of horses older than 15 are reported to have osteoarthritis [3].

The occurrence of arthritis varies depending on the discipline in which a horse works. As reported in a study [5], arthritis has been identified in 30% of two and three-year-old Thoroughbred racehorses. In another study that focused on endurance horses, arthritis was found via x-ray in 28% of fetlocks, 16% of pastern joints, and 7% of coffin joints [6].

What Causes Arthritis in Horses?

Osteoarthritis may be caused by:

• injury of joint cartilage, such as “wear-and-tear.”
• injury of cartilage and bone, such as chip fractures or osteochondrosis (OCD).
• inflammation of the joint itself (synovitis) and/or the joint capsule (capsulitis).

Inflammation that is not associated with cartilage or bone deterioration may be caused by instability of the joint or strain of the tissues supporting the joint.

How Does Arthritis Occur in Horses?

Osteoarthritis usually begins with low-level inflammation within the joint. When subjected to the stress associated with exercise and aging, your horse’s joints undergo a normal inflammatory response. If left unchecked, excessive inflammation may lead to long-term damage of the joint structures.

Over time, joint tissues may develop scarring and synovial fluid may lose its critical viscosity (protective, slippery quality). While articular cartilage may become damaged, and the bone underneath cartilage (subchondral bone) may become less able to absorb normal shocks during exercise.

The progression of osteoarthritis is accelerated if there is direct injury to the joint such as a chip fracture (osteochondral fragment). Osteoarthritis usually causes a progressive lameness that initially is low-grade and if it doesn’t respond to treatment, may progress to more severe lameness.

How Excess Inflammation Affects Joints

Inflammation results in the buildup of destructive enzymes in the joint. If not appropriately treated, the inflammation will lead to cartilage damage, changes in the bone around the joint surface, and thickening of the soft tissues associated with the joint. So-called “end stage” osteoarthritis is recognized when the cartilage and associated bone are so damaged that the joint begins to collapse.

Septic Arthritis in Horses

Septic arthritis is another category of joint inflammation that is due to bacterial infection of the joint that could result from a deep wound or puncture into the joint.

Septic arthritis may result in the same “end stage” that occurs in osteoarthritis. The initial cause is the introduction of bacteria within the joint that results in an infection. The inflammation caused by infection overwhelms the body’s defenses and destructive enzymes damage cartilage and may infect local bone.

Septic arthritis usually causes severe lameness - often non-weight bearing soreness that could be confused with a major bone fracture.

Equine Joints Commonly Affected by Arthritis

• Hock – Arthritis in the hock is also known as bone spavin. Every type of athletic work results in significant amounts of stress on the hocks of the horse’s back legs.
• Pastern – Osteoarthritis of the pastern joint is also referred to as ringbone. Pastern joint stress has been noted to lead to arthritis in studies on western pleasure, roping, reining horses, dressage, and jumping horses. Advanced pastern osteoarthritis results in considerable boney proliferation around the joint (ringbone - see figure 1 below).
• Fetlock – Research has shown that much like the pastern joint, even horses in lower levels of jumping and dressage work show arthritic changes within the fetlock joint.
• Knee – Arthritis of the knee is common in racehorses and somewhat less common, though it has been found in studies on upper-level dressage and rodeo horses.
• Navicular – Navicular syndrome is a general term that is used to describe pain originating in the heel of the foot. One of the potential causes of chronic heel pain, however, is arthritis of the navicular bone. This has been found in horses of all disciplines.
• Coffin – Arthritic changes in the coffin joint have been found in studies on western performance horses and are not uncommon in horses used in other disciplines.
• Vertebrae of the neck and back – The smaller joints of the vertebrae are called articular facets. The facets of the neck and back can also be affected by osteoarthritis.

Another boney response to joint inflammation is the creation of lips (osteophytes) at the joint margin or new bone at soft tissue attachments adjacent to the joint (enthesiophytes).

Signs of Arthritis in Horses

If you have started to notice some of the signs of arthritis in your horse listed below, be sure to talk with your veterinarian.

• Appearing stiff with uneven gaits and a shortened stride, intermittent lameness
• Reluctance to pick up, keep, or change a lead in the canter or lope
• Horses that work at high speeds - such as jumpers, reining, cutting and barrel horses - may become unwilling to stop or turn
• Recent appearance of toe dragging
• Farrier has difficulty holding up a leg or legs for trimming or resets
• Excessive, uneven horseshoe wear
• Poor performance with no medical cause

Senior horses are also more likely to show arthritic changes. Some more advanced signs of arthritis in older horses include:

• Enlarged joints or joints with reduced flexibility
• Reduced activity in turnout
• Easily apparent lameness
• Excessive resting of a limb

Diagnosing Arthritis in Horses

Diagnosis begins with a complete history and physical examination including palpation by a veterinarian. Next, the vet observes the horse’s soundness (with and without flexion tests) while jogged in-hand, lunged, and/or ridden. Nerve blocks may be helpful in localizing arthritis pain.

Once a problem in a particular joint is identified, it may be examined further through X-rays (radiography - figure 1 above), ultrasound, bone scan (nuclear scintigraphy), CT scan, or MRI.

Treatment for Arthritis in Horses

The most effective treatment approach includes direct medication of the affected joint by an intra-articular injection (IA) or when indicated, surgery such as arthroscopy (figure 2 below). This route is only effective for the joint or joints directly treated.

The next most effective route of treatment is intravenous (IV) or intramuscular (IM) medications. This involves the drug being distributed throughout the body and is effective for mild to moderate arthritis in multiple locations of your horse at the same time.

The oral route for medications includes non-steroidal anti-inflammatories (NSAIDs) and oral joint supplements. Keeping an arthritic horse in an exercise program where he’s walking and moving every day, within his comfort zone, is beneficial (unless your veterinarian advises otherwise).

Prescription Medications for Treating Arthritis

If your horse has been diagnosed with arthritis, prescription medications may be an important part of your horse’s treatment and management program. Consult your veterinarian to see if your horse could benefit from IV, IM, and/or IA joint medications.

Adequan® is the only FDA-approved, disease-modifying drug for the treatment of osteoarthritis. It contains polysulfated glycosaminoglycan (PSGAG), which is injected IM and travels to injured joints and reduces joint inflammation. It increases levels of joint hyaluronate which improves joint lubrication and may stimulate the repair of injured cartilage.

Legend® Injectable Solution provides hyaluronate sodium for IV or IA injection and is FDA-approved for the treatment of joint dysfunction of the knee or fetlock due to non-infectious synovitis associated with arthritis in horses.

For the management of arthritis, your veterinarian may also prescribe NSAIDs such as phenylbutazone (Bute; available in oral and IV forms), Equioxx® (as tablets or paste), or Surpass® Topical Cream, (rubbed into the skin over the area of inflammation).

Corticosteroids are among the most common anti-inflammatory medications injected into joints with arthritis. Use of corticosteroids in some horses, such as those with Cushing’s disease or metabolic syndrome, may be contraindicated, so always speak with your vet.

Polyacrylamide gel products (Noltrex®Vet, Arthramid®Vet) are available for treating joints with arthritis and result in reduced inflammation, increased joint fluid viscosity, and also fill cartilage defects.

Regenerative Therapies for Joint Health

Regenerative therapies based on biologic products that are derived from the horse’s own blood or tissue are becoming widely used for joint injections. Examples of these blood components include platelet-rich plasma (PRP), interleukin receptor antagonist (IRAP), a process that combines components of PRP and IRAP (ProStride®), alpha 2 macroglobulin (Alpha2EQ®), and stem cells [14]. The advantages of these biologic therapies are that no corticosteroids are used and some of the treatments have longer duration of action than traditional joint injections.

Alternative Medicine for the Arthritic Horse

Alternative treatment options are available for many of the processes that occur in the progression of arthritis.

• Chiropractic evaluation and treatment may help a horse with arthritis by improving spinal motion and thus, physical function.
• Applying cold therapy an affected joint will reduce pain and inflammation, while heat applications will relax tight soft tissues.
• Massage and stretching exercises will help enhance mobility of stiff joints.
• Acupuncture may be helpful for diagnosis and treatment of arthritis using Chinese Medicine techniques.
• Herbal therapies (also derived from ancient Chinese Medicine) that are formulated to treat arthritis. For example, turmeric is reported to have anti-inflammatory and antioxidant effects that may be useful in treating arthritis.

Check out our Therapy Guide to learn about other non-invasive methods to support health, performance, and overall well-being.

Supplements that Support Healthy Joints

When it comes to supporting healthy joints, many veterinarians agree that there is a role for both prescription joint medications and oral joint supplements.

While prescription medications are designed to help reduce inflammation and treat the signs of joint problems, while oral joint supplements provide key ingredients like glucosamine, chondroitin sulfate, and hyaluronic acid (HA) to offer daily support for healthy joint fluid and tissues.

Some oral joint supplements include resveratrol, which has anti-inflammatory and antioxidant activity throughout the body. Research has identified positive effects of resveratrol in horses with osteoarthritis. By providing the building blocks of healthy joint structures, you can help ensure your horse has everything it needs to keep it’s joints in good shape.

Click the link to learn more about common and cutting-edge ingredients in joint supplements for horses, and natural herbs, extracts, and antioxidants.

How Joint Supplements Work

Your horse’s body is designed to manage the normal “wear and tear” to joints that comes with being a horse in its natural state (constant roaming throughout the day, etc.). The increased demands of riding, training, and competing can put additional stress on your horse’s joint tissues.

Joint supplements help ensure your horse’s body has a consistent, ready supply of the ingredients it needs to cope with the stress of exercise and maintain healthy joints. And because joint supplements are designed to support normal, healthy joint tissues, the best time to start supplementing is BEFORE your horse starts displaying signs of joint problems.

How to Manage and Prevent Arthritis in Horses

The key to managing a horse of any age with arthritis is early recognition and appropriate treatment with the options discussed above based on your veterinarian’s recommendations.

While all horses are susceptible to developing arthritis, there are some factors that can increase your horse’s risk, including consistent stress on the joints from riding, acute injury, hoof imbalance, and poor conformation.

Keeping your horse fit and healthy with regular balanced trimming or shoeing is critical to maintaining a comfortable equine athlete. Whenever possible, work your horse on resilient, safe footing. Know your horse’s physical limits as a tired horse has fewer tools for concussion protection and careful limb placement. When your horse doesn’t appear or feel ‘right’ during work, connect with your veterinarian.

Evidence-Based References

1. Rodgers MR. Effects of oral glucosamine and chondroitin sulfate supplementation on frequency of intra-articular therapy of the horse tarsus. Intern J Appl Res Vet Med. 2006.
2. van Weeren PR, Back W. Musculoskeletal Disease in Aged Horses and Its Management. Vet Clin North Am Equine Pract. 2016 Aug.
3. Ireland JL, Clegg PD, McGowan CM, McKane SA, Chandler KJ, Pinchbeck GL. Disease prevalence in geriatric horses in the United Kingdom: veterinary clinical assessment of 200 cases. Equine Vet J. 2012.
4. Cantley CE, Firth EC, Delahunt JW, Pfeiffer DU, Thompson KG. Naturally occurring osteoarthritis in the metacarpophalangeal joints of wild horses. Equine Vet J. 1999.
5. Neundorf RH, Lowerison MB, Cruz AM, Thomason JJ, McEwen BJ, Hurtig MB. Determination of the prevalence and severity of metacarpophalangeal joint osteoarthritis in Thoroughbred racehorses via quantitative macroscopic evaluation. Am J Vet Res. 2010.
6. Hollenbach E, Robert MP, le Roux C, Smit Y. Prevalence of radiographic changes in forelimb digits and metacarpophalangeal joints of South African endurance racehorses. J S Afr Vet Assoc. 2022.
7. Ramos S, Pinto A, Cardoso M, Alexandre N, Bettencourt E, Monteiro S, Gama LT. Prevalence of Radiographic Signs of Osteoarthritis in Lusitano Purebred Horses. J Equine Vet Sci. 2020.
8. McIllwraith CW, Frisbie DD, Kawcak CE. The horse as a model of naturally occurring osteoarthritis. Bone Joint Res. 2012.
9. Espinosa-Mur P, Phillips KL, Galuppo LD, DeRouen A, Benoit P, Anderson E, Shaw K, Puchalski S, Peters D, Kass PH, Spriet M. Radiological prevalence of osteoarthritis of the cervical region in 104 performing Warmblood jumpers. Equine Vet J. 2021.
10. Dabareiner RM, Cohen ND, Carter GK, Nunn S, Moyer W. Musculoskeletal problems associated with lameness and poor performance among horses used for barrel racing: 118 cases (2000-2003). J Am Vet Med Assoc. 2005.
11. Dabareiner RM, Cohen ND, Carter GK, Nunn S, Moyer W. Lameness and poor performance in horses used for team roping: 118 cases (2000-2003). J Am Vet Med Assoc. 2005.
12. Swor TM, Dabareiner RM, Honnas CM, Cohen ND, Black JB. Musculoskeletal problems associated with lameness and poor performance in cutting horses: 200 cases (2007-2015). J Am Vet Med Assoc. 2019.
13. Gillespie CC, Adams SB, Moore GE. Methods and Variables Associated with the Risk of Septic Arthritis Following Intra-Articular Injections in Horses: A Survey of Veterinarians. Vet Surg. 2016.
14. Ribitsch I, Oreff GL, Jenner F. Regenerative Medicine for Equine Musculoskeletal Diseases. Animals (Basel). 2021.
15. Watts AE, Dabareiner R, Marsh C, Carter GK, Cummings KJ. A randomized, controlled trial of the effects of resveratrol administration in performance horses with lameness localized to the distal tarsal joints. J Am Vet Med Assoc. 2016.
16. Caron JP, Genovese RL. Principles and practices of joint disease treatment. In: Ross MW, Dyson SJ, eds. Diagnosis and management of lameness in the horse. Philadelphia: Elsevier, 2003.