Is your older horse developing a hitch in his get-along? Equine osteoarthritis is a common condition in the aging horse.

Osteoarthritis (also known as Degenerative Joint Disease) involves joint inflammation and progressive degeneration of the cartilage lining. It also involves changes in the bone and soft tissues of the joint.

Arthritis is thought to affect more than half of all horses over the age of 15. It is also the leading cause of lameness in horses. [1]

Horses engaged in high-intensity exercise, such as racing, may develop osteoarthritis at an earlier age due to wear-and-tear. [2]

There is no cure for arthritis, but with proper management, many horses can continue to live comfortably and maintain a good level of fitness.

A balanced feeding program that provides anti-inflammatory nutrients can help to support healthy joints. In addition, modified exercise routines, medications and therapeutic bodywork can also manage arthritic pain in your horse.

If you suspect your horse has arthritis, submit your horse’s diet online for free guidance from our equine nutritionists. Addressing this issue early on is critical to support your horse’s comfort and ease of movement.

Arthritis in Horses

Equine osteoarthritis is defined as a group of disorders characterized by progressive deterioration of the articular cartilage and other components of the joint. [2]

The major symptom of osteoarthritis in horses is pain manifesting as lameness, leading to a loss of functionality. Horses may also experience muscle stiffness, loss of performance, reluctance to work or swelling in the joints.

Osteoarthritis is not the only type of arthritis in equines, but it is the most prevalent and is what most laypeople mean when they refer to arthritis in horses.

Arthritis may also be caused by repetitive strain on the joints, such as the heavy workloads of performance horses, which can causes cartilage damage and erosion. In these horses, the metacarpophalangeal joint (fetlock) is the most likely to be affected.

Other types of arthritis include:

  • Septic arthritis: a potentially life-threatening condition that occurs when a joint becomes infected as a result of an injection, injury or surgery [3]
  • Traumatic arthritis: occurs after an injury, such as synovitis, or inflammation of the synovial membrane, joint capsule inflammation, chip fractures within the joint, ligament, or meniscus tears. Gradually, osteoarthritis can develop in the affected areas [3]

If you suspect your horse has arthritis or issues affecting joint mobility, seek out veterinary attention for an accurate diagnosis and appropriate treatment plan.

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Osteoarthritis Diagnosis in Horses

To diagnose osteoarthritis, the veterinarian observes the horse’s movement and conducts a physical examination. Questions are asked about the horse’s history, including current and former exercise programs. [6]

Diagnosis also typically involves flexion tests, in which pressure is applied to the limbs. These tests will temporarily make any existing joint pain more obvious.

Once the affected joint is identified, the horse receives a nerve block to anesthetize a part of the leg. After each block, the horse is prompted to move. When the lameness improves after a certain block, that indicates the problem joint.

Your veterinarian will also take X-rays of the affected joint. In some cases, the vet may recommend ultrasounds to get a better view of soft tissues.

Once the veterinarian has determined which joints are affected and how severely, a treatment plan is devised.

Causes of Arthritis

While horses as young as two years of age can develop arthritis, older animals are more often affected due to cumulative joint wear and tear.

Causes of arthritis in horses may include:

  • Constant concussive force during exercise
  • Improper shoeing
  • Joint trauma
  • Poor conformation

Some horses are conformationally predisposed to arthritis. Animals that toe in, toe out, or have upright pasterns or sickle hocks are more likely to develop arthritis.

Racehorses and other equine athletes are also at greater risk of developing joint problems. In one study, 33% of 2- and 3-year old Thoroughbred racehorses were found to have osteoarthritis and lesions in their articular cartilage. [4]

However, appropriate exercise is necessary for supporting proper joint development in young horses. Growing horses that are confined to stalls also have impaired cartilage formation and stunted joint development. [5]

Arthritis Symptoms

Lameness is the most common symptom of equine osteoarthritis, as well as swollen or tender joints.

Suspect possible arthritis if any of these signs are visible: [6]

  • Asymmetrical hoof wear
  • Bony bumps developing on a joint
  • Gait unevenness
  • Heat in the joints
  • Lead change issues
  • Popping or crackling noise from a joint
  • Shortened stride

These signs are not exclusive to osteoarthritis. They may also indicate soft tissue damage, such as ligament tears or a bone fracture.

Accurate diagnosis by a veterinarian is required before deciding on the best strategy for managing pain and limiting damage.

Prevention of Joint Problems

There is no fail-safe way to prevent arthritis in your horse, but there are steps you can take to help slow the progression of deterioration and keep your horse sound.

  1. Maintain appropriate hoof care: Keep your horse on a regular farrier schedule. Hoof care and proper trimming support biomechanics and help to reduce the concussive force on joints when moving. In contrast, imbalanced shoeing or inappropriate trimming can increase the risk of osteoarthritis by changing the load distribution and increasing pressure in the joints. [7]
  2. Include adequate conditioning in your exercise program: Chronic joint trauma, which can occur when the horse is in heavy, demanding work, contributes to degenerative joint disease. Ease your horse into heavy exercise by starting with low-intensity work and building up intensity and duration over a period of weeks or months.
  3. Allow young animals to exercise: Incorporate light exercise into your foal’s lifestyle. The light concussive impact of exercise stimulates cartilage formation and healthy bone development. This includes allowing free access to pasture, which has been shown to support optimal bone development. [5]
  4. Maintain a healthy body condition: Carrying too much weight puts excess stress on the joints. Obesity also increases inflammation in the body which can contribute to the development of arthritis. Keep your horse at a healthy body condition to reduce the odds of developing arthritis. [8]
  5. Develop a sound nutrition plan: It is important to provide appropriate levels of energy, protein, vitamins and minerals for optimal bone and joint development and to support horses with arthritis. Key nutrients to consider are amino acids, zinc, copper, calcium and phosphorus
  6. Consider joint health supplements: Feeding your horse supplements – such as MSM, DHA, and hyaluronic acid – that are backed by research can support mobility and joint health.

As the saying goes, an ounce of prevention is worth a pound of cure. Optimal joint health begins with proper nutrition and exercise in young animals.

If your horse displays signs of arthritis, consult with your veterinarian for an accurate diagnosis and contact an equine nutritionist to develop an appropriate diet plan for your horse.

Treating Arthritis in Horses

Before beginning to treat your horse for arthritis, make sure that you have an accurate diagnosis. If your horse is lame, it is important to identify any other potential issues contributing to your horse’s lameness.

Some horse owners think that if an older horse is lame, arthritis is automatically the culprit. That’s simply not true and you could make the situation worse without an accurate assessment of the problem.

Many common hoof health issues can cause lameness and may or may not coincide with joint health issues.

Always have a veterinarian conduct an examination to determine whether joint degeneration is the source of your horse’s lameness or whether they have another injury.

With careful management, many arthritic horses can continue to be ridden and used in sport disciplines, although often at a lower level of use.

Exercising Horses with Osteoarthritis

Some horses may benefit from short-term stall rest during flare-ups of symptoms. But, generally, regular low-impact exercise supports bone and joint health.

Arthritic animals benefit from lots of turnout and minimal time kept in a stall. Try to give your horse as much turnout as available.

Hyaline cartilage is a collagen-rich durable connective tissue found in synovial joints that assists with movement. Research shows that hyaline cartilage thickness is greater in trained compared to untrained horses. [9]

In one study of 2-year-old horses, training on sand and grass tracks improved the thickness of cartilage in joints after 13 weeks. [9]

Another study found that horses confined to box stalls had lower rates of cartilage protein synthesis compared to horses on a 6-week exercise program. [10]

Unexercised horses produced lower amounts of proteoglycans, which are heavily glycosylated proteins that make up the extracellular matrix of joint tissue.

Regular turnout is particularly important for younger, developing horses. In growing foals under the age of 5 months, free access to pasture supports optimal development of the musculoskeletal system. [11]

Pain Medications and other Pharmaceutical Treatments

Pharmaceutical interventions can help to manage the pain associated with osteoarthritis and reduce inflammation. Consult with your veterinarian to determine an appropriate treatment protocol involving medications.

Your vet may prescribe a non-steroidal anti-inflammatory drug (NSAID) to relieve inflamed joints.

Phenylbutazone

Phenylbutazone (bute, PBZ) is a commonly prescribed NSAID for arthritic horses that works as a cyclooxygenase inhibitor.

It inhibits the COX-1 enzyme that produces prostaglandins, which promote inflammation and fever. However, COX-1 is also found in the digestive tract where it is important for protecting the gastrointestinal cells from damage by acids. [12]

While bute has strong anti-inflammatory and analgesic (pain-relieving) properties, long-term use can cause ulcers in the gastrointestinal tract.

Equioxx & Previcox

Newer NSAIDs such as Equioxx and Previcox, are designed to be safer and have a lower risk of gut problems. These drugs are referred to as coxibs and they work by selectively inhibiting the COX-2 enzyme – or cyclooxygenase-2.

COX-2 also generates prostaglandins, the chemical responsible for pain and inflammation. However, COX-2 inhibition has less of a negative effect on the gastric mucosa lining the stomach. Long-term use of Equioxx and Previcox is less likely to cause ulcers. [13]

Tildren

Horses with distal hock pain may also benefit from Tildren® (Tiludronate disodium), a bisphosphonate compound. This drug works by inhibiting bone resorption to reduce bone degradation.

Intravenous infusion of tiludronate disodium in horses with osteoarthritis improved lameness scores and inhibited progression of osteoarthritis. However, it did not change markers of joint inflammation nor did it repair cartilage damage that already existed. [14]

Joint Injections

Regular joint injections help many horses manage arthritic pain, although they come with a higher cost. Your veterinarian can determine if your horse would benefit from this therapy.

Intraarticular injections take many different forms, including:

  • Corticosteroids
  • Hyaluronic acid
  • Polysulfated glycosaminoglycans (PSGAGs)
  • Platelet-rich plasma
  • Interleukin-1 receptor antagonist protein (IRAP)
  • Polyacrylamide hydrogel

Adequan

Adequan® is an FDA-approved equine PSGAG (polysulfated glycosaminoglycan) for the treatment of degenerative joint disease. Along with reducing lameness and swelling, Adequan® restores synovial lubrication.

PSGAGs work by stimulating the production of new cartilage in joints and by reducing inflammation. PSGAGs also appear to block enzymes that break down connective tissue and can reverse the cycle leading to cartilage component loss.

Adequan is indicated for intramuscular treatment of non-infectious degenerative and/or traumatic joint dysfunction and associated lameness of the carpal and hock joints in horses.

Adequan® administration consists of one vial (5 cc) of an intramuscular injection every four days for 28 days.

Topical Treatments

Liniments and other topical ointments were previously the primary treatment for horses with arthritis. They still hold an important place in equine care today.

A rubdown with a liniment helps soft tissues by increasing blood flow to the muscles. This helps improve nutrient uptake by tissues and supports healing.

Liniments are available in various forms including liquid, gel, and foam applications which allows horse owners to choose their preference.

Surpass

Diclofenac sodium, marketed under the brand name Surpass, is a topical NSAID approved by the FDA used for osteoarthritis symptoms.

The topical solution is applied directly to the affected area, such as the equine hock, knee, fetlock, and pastern joints. It helps to relieve inflammation and pain, supporting mobility. [15][16]

Formerly available only by prescription, diclofenac sodium is now available over-the-counter, but it is recommended to ask your veterinarian before using this NSAID.

Do not use diclofenac sodium if your horse receives another form of NSAID, such as Equioxx. Always wear gloves when applying diclofenac sodium.

Dimethyl Sulfoxide

Dimethyl sulfoxide (DMSO) is also used as a topical anti-inflammatory in horses, although it is not approved by the FDA for that purpose. It has been reported to have anti-inflammatory and antioxidant properties. [17]

Equine vets use it off