What is a joint?
A joint is a part of the body that connects two or more bones. Most joints in the body can move, which allows the bones to move in relationship to each other. Most movable joints are held together by an outer layer of tough, fibrous tissue called the joint capsule. The thin inner lining of the joint capsule, called the synovial membrane, produces joint fluid (synovial fluid) to lubricate the joint.
The ends of the bones are covered by a smooth layer of cartilage, called articular cartilage. The joint fluid and the articular cartilage reduce friction within the joint, allowing it to move smoothly. The articular cartilage does not contain any blood vessels to supply it with nourishment or oxygen. Instead, it receives some nutrients from small vessels in the bone underneath it and the rest by absorbing nutrients from the joint fluid.
What is degenerative joint disease (DJD)?
As dogs age, the tissues that line their joints deteriorate and degenerate. Degenerative joint disease (DJD), also known as arthritis or, more specifically, osteoarthritis, is the result of gradual, irreversible deterioration of articular cartilage in one or more joints. Arthritis is a general description of any condition that causes inflammation in the joints.
The smooth and resilient cartilage degenerates and becomes brittle over time. With severe DJD, degenerated cartilage may break away from the bone and become loose within the joint. DJD can occur following several joint diseases, including infection, and may develop after bone or joint injury or surgery. Obese dogs are more likely to develop DJD because of the chronic, low-grade inflammation caused by obesity and as a direct result of the mechanical stress that excessive weight puts on the joints.
Chronic, mild inflammation is involved in causing clinical signs. When the cartilage cells become damaged, they release substances that result in inflammation, causing pain and further damage to the cartilage. Once DJD begins, it can become a vicious cycle. As degeneration continues, the joint becomes more unstable. Scar tissue and/or bony growths form in the joint to stabilize it, further contributing to DJD.
What are the signs of DJD?
The most obvious sign of DJD in dogs is lameness; however, dogs also give many other signs that indicate they are suffering from arthritic pain, including:
- Sleeping more
- Walking more slowly or not wanting to walk as far
- Irritability when touched or brushed in certain areas
- Abnormal urination or defecation in the house
- Walking while urinating or defecating
- Slower to stand up from a lying down position
- Difficulty getting into the car
- Carrying the head or tail lower than normal
- Reluctance or inability to go upstairs, or jump on the bed or furniture
- Sitting with their hind legs stretched out (lazy sit)
Not every sign is observed in every dog with DJD.
Is DJD common in dogs?
OA is the most common chronic disease in dogs. By most estimates, 25% of all dogs are affected by OA, regardless of age. Approximately 40% of dogs up to four years of age show X-ray evidence of OA in one or more joints, and up to 60% of dogs show X-ray evidence of the disease in their lifetime. However, many dogs don’t show clinical signs of OA pain until they are older.
How is DJD treated?
Most of the damage caused by DJD is irreversible. The goals of treatment are to improve the dog’s quality of life by minimizing pain and discomfort and to delay the progression of disease. You can improve the quality of life for a dog with DJD by providing pain relief and by changing the environment so they can get around more readily.
Some suggestions for modifying the environment include:
- Provide steps or a ramp that allows the dog to get up to a favorite resting spot.
- Raise food and water dishes off the floor.
- Make sure all surfaces your dog needs to walk on are non-slip, including surfaces around food and water bowls. You can use carpet or yoga mats to make surfaces non-slip.
- Some dogs must be restricted from stairs to prevent pain or falls.
Encourage your dog to keep moving to maintain joint mobility and muscle tone. Weight loss to achieve a healthy body condition is also extremely helpful at relieving arthritic pain.
What medications can provide pain control in arthritic dogs?
Fortunately, modern analgesics (anti-inflammatory and pain-relieving medications) can effectively control pain with few side effects. In addition, medications and nutritional supplements may slow the progress of the disease and promote cartilage healing. Always get your veterinarian's advice before giving your dog any medication, and never give your dog any pain reliever meant for human use unless prescribed by your veterinarian. Many over-the-counter medications and human prescriptions can cause serious problems and side effects.
"Fortunately, modern analgesics (anti-inflammatory and pain-relieving medications) can effectively control pain with few side effects."
NSAIDS (nonsteroidal anti-inflammatory drugs) can be used to control inflammation in the joints and provide pain relief. Drugs used include meloxicam (Metacam®), carprofen (brand name Rimadyl®), deracoxib (brand name Deramaxx®), firocoxib (brand name Previcox®), and robenacoxib (brand name Onsior®).
A newer, injectable anti-nerve growth factor (NGF) antibody treatment (Librela®) can also be used to block one of the pain signals between the joint and the brain, helping your dog feel better.
Before giving your dog any pain medication, your veterinarian will recommend blood tests to ensure the liver and kidneys are functioning adequately and that there are no underlying problems that could be worsened by these drugs. Your veterinarian will also recommend periodic monitoring of your dog’s liver and kidney function once they begin treatment for this condition.
Other medications that may be prescribed to treat pain caused by DJD include:
- Gabapentin — an effective drug for relieving pain, especially when given with other pain medications. It can often allow for decreased doses of other medications. It is used in human medicine to treat neuropathic pain and seizures. It can be used alone for early arthritic pain.
- Tramadol — a mild relative of morphine without the side effects seen with morphine. It works very well on its own or in combination with other drugs to provide pain relief. Rarely, it can cause constipation or vomiting.
- Amantadine — a pain reliever that blocks the sensation of pain at the nerve pathways. It is not effective as a sole medication but increases the pain-relieving effect of other medications.
Your veterinarian may recommend injections of chondroprotectants (brand names Adequan® or Cartrophen®). These medications promote cartilage repair, help slow down cartilage damage, aid in other aspects of joint repair, and stimulate the production of more joint lubricating fluid.
Are diets or supplements helpful in controlling the pain of DJD?
Ongoing arthritis research has led to therapeutic diets that are formulated specifically to control the discomfort associated with DJD and to delay the progression of the disease. These therapeutic diets (including Royal Canin® Mobility Support and Hills® Prescription Diet j/d®) are available only through your veterinarian.
Nutraceuticals are nutritional supplements rather than pharmaceuticals (or drugs):
- Omega-3 fatty acids are powerful antioxidants that help relieve inflammation in arthritic joints and are proven to decrease pain in dogs with arthritis. They are a useful treatment in conjunction with other medications for any patient experiencing DJD or osteoarthritis.
- Undenatured type II collagen (Flexadin Advanced®) helps to modulate the inflammatory process in the joint and may reduce cartilage degradation.
- Green-lipped mussel (Antinol®) contains another fatty acid that has also shown promising evidence to help dogs with DJD.
- Two of the most used supplements are glucosamine and chondroitin. Some small research studies and numerous anecdotal case histories suggest these products are beneficial, and they appear to be free of side effects.
Some supplements are available over the counter (without a prescription). Since supplements are not highly regulated, some may not contain the labeled amount of ingredients and there may be quality differences between products made by different manufacturers. Your veterinarian may recommend a trusted brand.
What other treatments are available for treating DJD in dogs?
Rehabilitation is a growing area of veterinary medicine similar to human physiotherapy. Certified rehabilitation practitioners offer many treatments for arthritis, including laser therapy, hydrotherapy, ultrasound, and muscle therapy. Acupuncture may also be an effective tool for pain relief.
Stem cell therapy and platelet rich plasma (PRP) injections are also used to treat arthritic patients in some veterinary clinics and referral hospitals. If you have any questions or concerns regarding the care and treatment of your dog, contact your veterinarian.