Arthritis
Degenerative joint disease (osteoarthritis)
Degenerative joint disease (DJD) is caused by the breakdown of articular cartilage, secondary to inflammation within the joint. A vicious cycle occurs in which inflammation causes the loss of proteoglycans (molecules that hold moisture in the joint lining) from the cartilage, reducing the cushioning of the joint, which then causes even more inflammation and so on. DJD may be caused by poor conformation or trauma.
Signs
There is often distention (swelling) of the joint with reduced motility of the joint and pain when it is flexed.
Lameness is usually slight and intermittent having grumbled along for a while, however, will often gradually worsen over time. DJD may be caused by poor conformation or trauma.
Diagnosis
X-rays will often show obvious changes within the joint or in some cases of trauma, a fracture, however, in the early stages no abnormalities may be found. Retrieving a sample of the synovial fluid from the joint will show evidence of inflammation and a joint block will confirm the diagnosis.
Treatment
Treatment is aimed at reducing the inflammation and preventing/reducing cartilage damage. Horses with acute arthritis should be rested and regular cold water hosing employed. Anti-inflammatory drugs such as phenylbutazone (‘bute’) and feed supplements containing chondroitin and glucosamine sulphate are often used to great affect. Agents are often injected directly into the joint such as corticosteroids, to reduce inflammation, and hyaluronic acid, to help repair cartilage. Other drugs can be injected at regular intervals into the muscle of the horse and have a similar effect as those injected into the joint. Surgery can be performed to flush the joint to dispose of any debris and inflammatory cells that contribute to the damage. In some cases of DJD when there are severe changes within the joint and a persistent lameness the joint can be surgically fused (arthrodesis).
Traumatic arthritis
Traumatic arthirits is inflammation within the stifle joint and may be caused by trauma or poor conformation. There is often distention (swelling) of the joint with reduced motility of the joint and pain when it is flexed. Lameness may be slight and intermittent or may be more severe and have occurred more suddenly.
Diagnosis
X-rays will often show no obvious changes within the joint, these changes often take a long while to occur, unless a fracture is present. Retrieving a sample of the synovial fluid from the joint will show evidence of inflammation and a joint block will confirm the diagnosis. If no cause can be found and the horse remains lame after a period of treatment surgery can be performed to see inside the joint using an athroscope (key-hole surgery). This is often necessary as there are many structures than cannot be seen using normal diagnostic tools. In performing this surgery there is a better a chance of finding a diagnosis and then attempting treatment if possible at the same time.
Treatment
Treatment is aimed at reducing the inflammation and preventing/reducing cartilage damage. Horses with acute arthritis should be rested and regular cold water hosing employed. Anti-inflammatory drugs such as phenylbutazone (‘bute’) and feed supplements containing chondroitin and glucosamine sulphate are often used to great affect. Agents are often injected directly into the joint such as corticosteroids, to reduce inflammation, and hyaluronic acid, to help repair cartilage. Other drugs can be injected at regular intervals into the muscle of the horse and have a similar effect as those injected into the joint. As explained above key-hole surgery can be performed to flush the joint to dispose of any debris and inflammatory cells that contribute to the damage as well as aiding in finding a diagnosis. Treatment is best carried out a soon as possible to reduce the chances of further problems, e.g. degenerative joint disease (DJD).