Technical information for veterinarians
Degenartive Joint Disease (DJD) in Horses
What is Degenerative Joint Disease (DJD)?
DJD (degenerative joint disease or osteoarthritis), causes lameness in affected horses. The condition develops when the cartilage that protects the bones of the joint is destroyed. Although it may develop in any joint, areas most commonly affected include the upper knee joint, front fetlocks, hocks, and coffin joints in the forefeet. Degenerative Joint Disease (DJD) may result from injury, loose joints, an abnormal growth pattern, or inherited factors.
Over time, the cartilage may erode entirely, resulting in bone-on-bone grinding and further disability. Although Degenerative Joint Disease (DJD) can affect any joint, it usually affects the:
- Hocks (ankles) where it is commonly referred to as Bone Spavins – common
- Fetlocks – common
- Pastern joints and Coffin joints where it is referred to as Ringbone when more severe – common
- Stifle (knee) joints – less common
- Spine (neck and back) – less common
Degenerative Joint Disease (DJD) is one of the most common causes of lameness in sport horses.
Etiology of Degenerative Joint Disease (DJD)
The development of Degenerative Joint Disease (DJD) involves a complex chain of events. Dr. Sheila Laverty, professor, Faculty of Veterinary Medicine, University of Montreal, describes the etiology and pathogenesis of Degenerative Joint Disease (DJD) as follows: The condition generally starts with trauma and ends with soft, yellow, fibrillated and ulcerated cartilage, eburnation and sclerosis of the subchondral bone, hyperplasia of the synovial membrane and a thickened fibrous joint capsule, periarticular osteophytes, osteolysis, ankylosis in low motion joints and a decreased range of motion in high motion joints.
Click here for Dr. Laverty’s in-depth explanation of the etiology and pathology of osteoarthritis
A horse’s risk of developing Degenerative Joint Disease (DJD) increases with age. In some cases degenerative arthritis may be hereditary. (The tendency for defective cartilage and/or defects in the way joints engage such as hip dysplasia, navicular syndrome and OCD, can be passed down. The end result, Degenerative Joint Disease (DJD), may not be clinically identifiable until the horse experiences trauma to the genetically weakened area.)
Since excess weight puts stress on the weight-bearing joints, heavier breeds and obese horses are more prone to the condition. Repeated overuse and injury of a joint can damage the cartilage and be a contributory factor.
Improper shoeing can cause problems in the muscles and joints, leading to Degenerative Joint Disease (DJD).
Symptoms/diagnosis of DJD
The following symptoms are indicative of Degenerative Joint Disease (DJD):
- Pain, stiffness and swelling around a joint that lasts longer than two weeks.
- In the early stages of the disease, an affected horse’s joints may ache after activity.
- Stiffness that tends to follow periods of inactivity, such as sleep or prolonged standing.
- Crepitus upon joint use.
- Decreased performance and inability to perform activities that were once performed with ease.
- Appearance of bumps or swellings, especially on the extremities.
If the horse’s joints are red or feel hot or tender, autoimmune or septic arthritis should be considered.
A thorough orthopedic examination can reveal the presence of joint pain, swelling and tenderness. A careful history will also point toward a specific primary disease process. Radiography is also useful in making a diagnosis, since the majority of degenerative arthritis seen in small horses is secondary to some congenital disorder or traumatic event.
Usually the diagnosis of degenerative arthritis is fairly straightforward, however, the use of additional views or “stress” views may be necessary. Injecting contrast (dye) into the joint and obtaining a radiograph is rarely considered necessary. Advanced imaging techniques such as CT and MRI are seldom helpful in making a diagnosis.
Bone scans may be helpful, since an area of increased accumulation of radioactive material may help the clinician detect a subtle area of lameness.
Although used primarily as a research tool to assess a degree of lameness and response to various treatment modalities, the force plate can be used in the clinical setting to help evaluate the degree of lameness. A plate or mat is placed on the floor and the horse is encouraged to make numerous passages across the plate. Sensors in the plate are attached to a computer that analyzes the force each step makes on the plate. A number of variables can occur, but force plate analysis can be helpful.
Degenerative Joint Disease (DJD) is one of many types of joint disease that affect horses. Other joint diseases are, for the best part, inflammatory in nature. When these diseases are present, a significant amount of white blood cells are attracted to the joint. The most common inflammatory joint diseases are autoimmune in nature. Aspiration of the joint fluid can be helpful in determining if the arthritic process is inflammatory (autoimmune or septic) or non-inflammatory (degenerative joint disease).
Treatment – Degenerative Joint Disease (DJD)
Once a diagnosis of Degenerative Joint Disease (DJD) has been made, the appropriate course of treatment can be determined. The chosen treatment will depend on the severity of the disease and the amount of work the horse is expected to perform. On occasion, stall rest and use of ice packs is all that is needed to reduce inflammation and swelling. Treatment for established arthritis normally includes analgesic and anti-inflammatory medications, exercise management and, occasionally, surgery.
Analgesic and Anti-inflammatory medications
Ideally, these should only be used for the short term, when necessary to encourage movement. Although the horse may respond quickly to anti-inflammatories, this is usually because they are quelling pain, and not because the condition itself is improving. In most cases these medications act simply as painkillers, and should only be used in addition to lifestyle modifications including good exercise management.
Commonly used analgesics and anti-inflammatories include acetaminophen and various NSAIDs (non-steroidal, anti-inflammatory drugs).
For mild to moderate arthritis in horses, your veterinarian may recommend acetaminophen (Tylenol®, Panadol®, Exdol®, etc.) to relieve pain. Since acetaminophen is only a pain reliever and has no anti-inflammatory properties, it can generally be safely combined with anti-inflammatory medications.
Too-high doses of acetaminophen can cause liver damage.
Non-steroidal anti-inflammatory drugs (NSAIDs)
NSAIDs help reduce the pain and swelling of the joints and decrease stiffness. When taken at a low dose, NSAIDs reduce pain; when taken at a higher dose, NSAIDs can also reduce inflammation.
NSAIDs do not prevent joint damage and when used long-term, may accelerate joint breakdown. Taking more than one NSAID at a time increases the possibility of severe side effects such as ulcers and bleeding. NSAIDS affect normal blood clotting and therefore may interact with other blood-thinning medications, such as warfarin.
Cortisone is a corticosteroid that reduces inflammation and swelling. For severe pain and inflammation, a corticosteroid, such as cortisone, may be injected directly into the affected joint. Although corticosteroids closely resemble cortisol, they exert a much more powerful anti-inflammatory effect. An injection can provide almost immediate relief for a tender, swollen and inflamed joint.
Visco-supplementation is the process of injecting a gel-like substance into the joint. This substance lubricates the cartilage, reducing pain and improving flexibility. Visco-supplementation decreases friction within the joint, thus reducing pain and allowing greater mobility. This method of treatment requires ongoing injections as benefits are only temporary. Substances used in visco-supplementation include hyaluronic acid, or HA (Legend®, Hylartin® and Synacid®), and poly-sulfated glycosaminoglycans (PSGAGS) such as Adequan®
Reducing the risk of DJD
Certain breeds of horse may pass along the tendency for defective cartilage or slight defects in the way joints fit together. These defects include hip dysplasia, navicular syndrome, osteochondrosis (OCD), and osteochondritis, all of which may lead to Degenerative Joint Disease (DJD) later on in the horse’s life. It is important that owners observe the following lifestyle modifications, to reduce the horse’s individual risk factors or to help halt the progression of existing Degenerative Joint Disease (DJD).
Traumatic injury to hock, stifle, pastern and fetlock joints increases the horse’s risk for developing Degenerative Joint Disease (DJD) in these joints. Joints (such as the hocks), that are used repeatedly in certain activities may be more likely to develop Degenerative Joint Disease (DJD) because of injury or overuse.
- Dietary managementWeight control is an important component of any treatment for Degenerative Joint Disease (DJD). (Excess weight puts more pressure on the weight-bearing joints, particularly the knees and hips.) If overweight is contributing towards the condition, the horse should be placed on an appropriate diet.
- Exercise managementExercise is an important component of healthy living. Exercise helps reduce pain, prevents further joint damage and can help the horse maintain a healthy weight. Disuse of a sore joint will cause the muscles around it to weaken, resulting in pain. Owners should be encouraged to exercise an affected horse gently and frequently.
- Adequate restSome horses, particularly working animals, do not get adequate rest for optimum healing. Owners should be apprised of an appropriate resting schedule for a horse suffering from Degenerative Joint Disease (DJD).
- Proper shoeingImproper shoeing can cause many joint and muscle problems and is a significant factor in the progression of degenerative disease.
- Use of lifestyle supplementsThe prudent use of lifestyle supplements that help to suppress the action of free radicals in the tissues may help horses at risk for Degenerative Joint Disease (DJD). Bioflavonoids, including those derived from Camellia sinensis and Vitis vinifera, have been reported in numerous studies to help maintain tissue integrity.
Equine health options
Recovery®EQ with Nutricol®, is an elite proprietary performance and wellness supplement for horses that enhances quality of life. Recovery®EQ improves healing by increasing circulation of nutrients to affected cells and extracellular structures, halting tissue damage and decreasing inflammation. It may be used on its own or in combination with prescribed medications.
Review in the prestigious Horse Journal in October and December 2003
Recovery®EQ rated as “Best Performer Overall” as a pain-relieving supplement for joint pain, back pain and tendonitis – comparison of natural joint care supplements.
Review in the prestigious Horse Journal in June 2006:
“You get what you pay for” – Horse Journal quote about Recovery®EQ used as a performance enhancing supplement – comparison of natural performance enhancing supplements