Hi again! So glad you’re here! Today we are going to talk about arthritis – specifically osteoarthritis. There are some pretty remarkable numbers regarding the incidence of arthritis in our pets:
- 20% of all pets over the age of one year have arthritis (that’s 1 in 5!)
- 60-65% of pets over the age of six years have arthritis (more than half!)
- 90% of pets over the age of twelve years have arthritis (almost everyone!)
Vocabulary
Arthritis by definition means inflammation of the joints (from ‘arthro-’ = joint, and ‘-itis’ = inflammation.) In human medicine this term actually encompasses about 200 conditions affecting the joints and surrounding tissues.
Osteoarthritis is the specific term for arthritis as most of us think about it: stiff, achy joints that most commonly are seen in people (and pets) starting around middle age. For the sake of simplicity osteoarthritis will be referred to as arthritis or OA for the rest of this lesson.
Another term you may hear used to describe age-related joint changes is Degenerative Joint Disease (DJD). DJD and OA are interchangeable in most instances.
Why does arthritis occur?
If you perused the Anatomy and Physiology lesson, you may recall that arthritis occurs via one of two processes:
- Normal forces through an abnormal joint
- Abnormal forces through a normal joint
Both of these processes cause erosion of the protective cartilage of the joint. As this cartilage is worn down, bone-on-bone contact can occur, which causes lots of inflammation and pain. This inflammation can cause secondary changes like soft tissue swelling, bone spur formation, decreased flexibility and range of motion, and loss of muscle mass.
Let’s look at each of those two processes individually:
Normal forces through an abnormal joint
This is the most common cause of arthritis. Common causes of mechanically abnormal joints include developmental conditions (such as elbow dysplasia, hip dysplasia, osteochondritis dissecans, congenital deformity, etc) and trauma which affects the joint. Because the normal forces (generated by gravity and movement) are not through the strongest and most protected parts in an abnormal joint, microinjuries occur which ultimately lead to arthritis.
Other conditions that cause inflammation in the joint (such as joint infection and auto-immune conditions) can also set off an inflammatory cascade which leads to arthritis, even if the inciting condition resolves.
Abnormal forces through a normal joint
Abnormal forces can include repetitive injuries, high-velocity or high-impact forces, abnormal gait, obesity and other external forces acting on otherwise normal joints. Generally, these injuries set off a cascade of inflammation which alters the normal environment of the joint – that is, an abnormal force through a normal joint leads to an abnormal joint. Once inflammation has been initiated, it can be very difficult to alter progression of arthritis.
Let’s look a bit closer
The cartilage in a joint is called articular cartilage. It acts as a protective covering over the end of each bone in a joint. Within the joint space is synovial fluid, which helps to lubricate the joint and nourish cartilage.
Cartilage is notoriously bad at healing. If the cartilage is damaged, it is unlikely that it will heal effectively. In some situations a new type of cartilage (fibrocartilage) can grow into an injured area, but it is a poor replacement for articular cartilage.
So if cartilage damage is permanent, what can we do about arthritis?
With treatment, we can slow the progression of arthritis – but once it has started the progress cannot be halted completely. Treatment may include surgery, medications, supplements, weight loss, and complementary treatments such as acupuncture and rehabilitation.
Here are some examples of how each of these treatments may help:
Surgery: stabilize the stifle with a TPLO, modify the hip joint with an FHO, debride the shoulder with OCD.
Medications: use anti-inflammatory medications (such as Rimadyl)
Supplements: glucosamine/chondroiten (Dasequin), fatty acids (Welactin), PSGAGs (Adequan) can help contribute to joint health and decreased joint inflammation
Weight loss: fat is inflammatory and increased weight means joints have to work harder
Acupuncture: decreasing pain can contribute to better mobility and more energy
Rehabilitation: joints in motion tend to stay in motion. Encouraging healthy activity with therapeutic exercise can help normalize the forces through joints while also decreasing pain and stimulating the brain.
Wait, can arthritis be prevented?
Although there is no surefire way to stop your pet from getting arthritis, there are some things you can do to help delay the onset and slow progression.
Keep your pet in a good body condition. Check out the Resources tab for some body condition scores that can help you understand healthy body condition in your pet. If you have a question about your pet’s body condition, as your veterinarian or make an appointment with Dr. Rushing to discuss weight management plans.
Keep your pet active. Regular daily activity is better for the body than “weekend warrior” type activities. This could mean a short leash walk each evening, playing in the house or yard, going to doggy daycare, or whatever other daily activity you and your pet enjoy.
Treat injuries in a timely fashion. If your pet is limping, favoring a leg, or seems uncomfortable in any way you should see a veterinarian within the first few days. The longer you wait, the greater the risk of developing arthritis down the road.
Consider joint supplements. Glucosamine/chondroiten and fatty acids are easy to purchase over the counter and are easy to administer. Research has generally shown mild efficacy, with minimal side effects. Adequan (an injectible joint supplement) is prescription-only, but has the strongest body of science supporting its efficacy. If you have an active pet or a breed prone to joint or bone issues, these supplements should be started early in life – before any problems have developed.
Do you have an aging pet? Maybe your pet could stand to lose some weight?
Are you wondering if there is more you can do to keep your pet comfortable in their later years? Grace Veterinary Services can help your pet continue to age gracefully.
Thanks for reading! Come back next week to learn about Obesity in Pets.
