Arthritis (Osteoarthritis) in Horses

Osteoarthritis is very common in horses, and is a common reason for retirement in athletic horses. Horses showing signs of lameness require prompt examination by a veterinarian to determine the underlying cause. Osteoarthritis cannot be cured, so prompt diagnosis allows for management strategies to be implemented to prevent further damage to the joints.

Specific forms of arthritis are characterized according to which joint is affected, including bone spavin, osselets, and ringbone.

The lameness resulting from osteoarthritis can vary significantly, depending on the joint affected and the severity of disease. Some horses are only mildly lame, showing symptoms such as poor performance or exercise intolerance.

Horses that develop more severe disease show more pronounced lameness, including lameness that is visible at the walk. These horses often show signs of limited mobility, including:

• Difficulty with farriery
• Difficulty rising or unwillingness to lay down
• Reduced movement in the pasture
• Pain, difficulty, or unwillingness to walk in deep surfaces such as mud or snow
• Reduced range of motion in the joints

Horses who are most at risk of developing arthritis include horses in intensive athletic sports, horses with poor conformation, or horses with previous joint injuries or conditions.

Osteoarthritis is a degenerative condition, where the joint surfaces become progressively worn down or damaged over time. The exact cause of arthritis is unknown, however the wearing down of cartilage is usually associated with one of three basic factors:

• Abnormal force or load on a normal joint
• Normal force or load on an abnormal joint
• Previous damage to the joint that continues to worsen with normal force or load

Most cases of osteoarthritis in horses occur due to abnormal force or load affecting a normal joint, which occurs with consistent, repetitive athletic training.

Abnormal limb conformation leads to abnormal weight bearing across the joint and contributes to arthritis, even under moderate or light workloads. Other contributing factors include previous joint damage.

Symptoms of osteoarthritis in horses depend on the joint affected.

Diagnosis of osteoarthritis may require several tests, including:

• Physical examination
• Lameness examination
• Diagnostic imaging
• Advanced diagnostic imaging such as bone scans or MRI
• Arthroscopy of the joint capsule

Osteoarthritis cannot be cured, so treatment focuses on managing pain and reducing the progression of disease. The precise treatment depends on the joint affected, severity of disease, the horse’s environment, and current level of activity.

Management strategies include:

• Post-exercise cold hosing or ice booting to reduce swelling
• Long-term pain medication
• Intravenous medications that support joint health, such as hyaluronic acid or glycosaminoglycans
• Joint injections of medications that reduce inflammation and support joint health
• Arthroscopy to remove damaged cartilage and bone
• Surgical fusion of the joint

Note: Several oral supplements, such as chondroitin and glucosamine, are available for horses. There is minimal evidence to support using these products in horses, and they have not been shown to be effective against equine arthritis for either prevention or treatment. Always consult a veterinarian before administering medication to animals, even if they are approved for veterinary use.

Osteoarthritis continues to progress over time, often requiring a reduction in physical activity. As arthritis progresses, affected horses are often retired due to soundness issues. Horses with mild osteoarthritis may remain sound for years with appropriate management. More severely affected horses can often be kept “pasture sound” and maintain a good quality of life through their retirement.

There are no confirmed preventatives for osteoarthritis. General recommendations focus on reducing joint damage and allowing time for joint repair. Examples include:

• Reducing repetitive training through cross-training, rest periods, or varying the type or intensity of training
• Replacing workouts on hard surfaces with swimming, if available
• Slow, progressive training to establish fitness and muscle strength before increasing athletic activity
• Cold hosing or ice booting horses after hard workouts
• Close monitoring for any changes in soundness or performance that may indicate osteoarthritis is developing
• Maintaining optimal body condition; avoiding obesity

Osteoarthritis is very common in horses.

• Reduced activity
• Joint injections
• IV medications to support joint health
• Surgical interventions
• Pain medications