Arthritis is a progressive and permanent deterioration of articular cartilage, specifically the type of cartilage that lines the ends of bones where they come together to form a joint. Healthy articular cartilage produces a smooth, slippery surface that allows free movement and contributes to the shock-absorbing properties of the joint. As arthritis sets in, articular cartilage becomes compromised, which disrupts the normally smooth surface, causing stiffness and discomfort.
Arthritis is one of the most common conditions that affect performance and pleasure horses. In fact, arthritis is believed to be responsible for up to 60% of all lameness. The joints most often affected by arthritis include the knee, fetlock, coffin and pastern (often referred to as “ringbone”). Whether the condition appears suddenly after trauma or gradually with worsening stiffness, it means the same thing. Chronic inflammation has led to permanent degradation of the cartilage in a horse’s joints, damage which is irreversible.
Joints have several components:
Collateral ligaments – Prevent lateral movements of the bones
Synovial fluid – Fills the space between the bones and provides lubrication and nourishment to the cartilage
Joint capsule – Stabilizes the joint
Synovial membrane – Regulates the joint fluid
Articular cartilage – The soft structural tissue that covers and cushions the ends of the bones
A 1999 study published in the Equine Veterinary Journal concluded that arthritis was a natural part of the aging process in horses. This means that it is not just horses in heavy work that are at risk – all horses are at risk for developing arthritis, even those in light work or no work at all.
Joint damage can be categorized into distinct stages:
Synovitis is inflammation of the synovial membrane. The primary cause of synovitis is overstretching of the synovial membrane during demanding exercise. Swelling due to an increase in joint fluid production is the most obvious sign. This accumulation of fluid is called joint effusion, common in racing thoroughbreds and other horses worked strenuously. Synovitis can usually be calmed with a layoff from strenuous exercise.
Degenerative joint disease (DJD) can occur if synovitis goes untreated, causing damage to the cartilage surface to develop. This deterioration of the cartilage is the next stage of articular breakdown. DJD is characterized by chronic, progressive degeneration of the joint cartilage and is found most frequently in the fetlock and knee, but is also diagnosed regularly in the pastern and hock. Two primary processes lead to DJD:
Osteoarthritis is distinguished from DJD by changes in the bone that comprise the joint. These changes severely impede mobility and soundness. The inflammation process goes largely unnoticed unless significant swelling is present.
There are several different types of arthritis in horses, but the most commonly reported are:
Common Causes of Arthritis
Arthritis is caused by the slow wearing of cartilage. Over time, compression and stress wear away the protective cartilage. Causes of arthritis include:
It is best to look for and discover the disease early since treatment is much more effective in the early stage. Arthritis onset may not be obvious as signs may be absent or there may only be a little joint swelling which is easy to miss.
Indications arthritis is developing include:
It is important to be proactive to minimize joint damage and prevent DJD. Activities that can assist in the management of arthritis include:
Treatments for Arthritis
Early treatment is extremely important and often has excellent results. Many cases of joint pain and inflammation can be successfully treated with a combination of rest and medication, including nutritional supplements. Treatments often include:
Cost of Treating Arthritis
In the United States, the cost of treating arthritis is estimated to range between $1,000 and $4,000 per occurrence and average $2,500. Consequently, a prevention plan including regular examination and use of nutritional supplements can be a cost-effective way to minimize future treatment costs.