Osteoarthritis (OA) is a joint disease that causes the cartilage to break down and bone to overgrow or form cysts. Cartilage is a smooth, shiny material that lines the joints – allowing them to glide easily as you move. It is a type of resilient connective tissue that covers and protects the ends of bones in joints. Although OA can affect any joint in the body, it most frequently affects the hips, knees, hands, feet, and spine.
Arthritis is among the leading causes of disability in Canada. OA is the most common form of arthritis. It affects 1 out of every 10 people in this country. Statistics show that men and women are affected in equal numbers up to the age of 55.
After menopause, women tend to have more severe and complicated problems. OA usually occurs after the age of 45, but it can occur earlier in life, and even be seen in the spines of teenagers. It is present, even if not causing symptoms, in virtually all people over the age of 80.
Risk factors for developing OA include:
- increasing age
- having a family member with the condition
- repeated injury to the joint through sports or work
- being overweight
- having another form of arthritis
There's no cure for OA, although research is beginning to unravel the mechanisms of the disease, which should lead to new treatments. Treatments currently focus on managing pain, reducing the load on the joints, and improving the strength of the muscles supporting the joints. Experimental therapies try to slow the progression of the disease and increase the mobility and flexibility of the joints.
As you move or put pressure on a joint, cartilage allows bones to slide over one another and acts as a shock absorber.
Cartilage itself does not have any nerve cells and therefore cannot sense pain. OA results when the cartilage becomes worn out, allowing the bones underneath to rub against each other and cause pain and swelling. It is not simple wear-and-tear but a process involving the cells and proteins of bone and cartilage.
As the condition progresses, the joint may become disfigured and small growths called osteophytes begin to grow inside the joints. Osteophytes are small, irregular, bony growths that are also called bone spurs. Bits of broken-off cartilage or bone are also found floating inside the joint. This causes even more pain, swelling, and immobility of the joint.
The exact cause of these changes is unknown. Scientists believe that the following factors play a role:
- increasing age: The cartilage wears down with time. By age 65, 80% to 90% of people have OA, as shown on X-ray, though a much smaller percentage has symptoms.
- family genes: Scientists believe that OA may be passed on through families, with the symptoms appearing in middle age.
- being overweight: Excess weight puts stress on weight-bearing joints such as hips and knees, and increases the risk of cartilage breakdown. This is the most important risk factor for OA affecting hips, and leg and foot joints.
- injury: Trauma to the joint, such as overuse, can damage the cartilage and lead to OA. This is often the cause of OA in younger people.
- infection: Infection of the joint may lead to arthritis
- other types of arthritis: For example, rheumatoid arthritis can also damage joints and lead to OA.
Symptoms and Complications
The following are symptoms of osteoarthritis (OA):
- deep, aching joint pain, sometimes sharp, with activity; the pain can persist at rest
- transient joint stiffness after a period of rest (such as getting up in the morning or after a long time spent sitting)
- swelling and stiffness in one or more joints
- enlarged middle- or end-joints of the fingers or the base of thumb
- a crunching feeling or sound when moving joints
- loss of joint flexibility
- back and neck pain and stiffness
Weight-bearing joints such as hips, knees, and feet are more prone to OA. It is important to note that many people have OA but don't experience any symptoms. Often, the onset is gradual with only one or a few joints. The symptoms of OA can be made worse by overusing the joints.
Making the Diagnosis
Most doctors use a number of methods to diagnose OA including:
- your description of signs and symptoms, when it started and how it is affecting your life
- a physical examination of affected joints, including an assessment of flexibility, mobility, and deformity
- analysis of X-rays of the joints to identify cartilage loss, bone damage, and the presence of osteophytes; in some cases, doctors may also request an MRI
- analysis of fluid from the affected joint (joint aspiration)
- blood tests to rule out other causes of joint problems
- bony protrusions of the middle joints (called Bouchard's nodes) and the end joints (called Heberden's nodes) of the fingers
Treatment and Prevention
Treatments include physical therapy to improve mobility and flexibility, weight management, medications to manage pain, and surgery.
Talk to your physiotherapist or occupational therapist about "aids of daily living" such as canes, walkers, and braces if you have OA.
Non-prescription medications may be sufficient to treat pain and swelling for milder symptoms, but prescription medications are needed for more severe symptoms. The following are commonly used medications to treat OA:
- acetaminophen* reduces mild-to-moderate pain
- NSAIDs such as ibuprofen or naproxen reduce both pain and swelling
- topical medications such as diclofenac or capsaicin lotion may be used for very mild pain or in addition to other treatments
- duloxetine can reduce knee pain caused by osteoarthritis
- narcotic pain relievers should only be used to treat severe pain for short periods of time
- cortisone, which is injected directly into the joints, can relieve pain and swelling
- hyaluronic acid injections into joints are used to relieve pain and improve mobility, but there is disagreement about their usefulness
- many major studies of the supplements chondroitin or glucosamine have shown mixed results for pain relief, though many patients feel that they work
Surgery is an option if one joint is badly damaged or is causing severe symptoms. Different types of surgical options are available and include joint replacement, arthroscopy (a procedure where a small, flexible tube is inserted to do surgery), repair of bone deformity, rebuilding of the joint, or bone fusion. Joints that may benefit from surgery include knees, hips, shoulders, and certain joints in the hands and the feet.
For people with hip and knee OA that has progressed to the point of disability, joint replacement surgery is highly effective and a reasonably safe treatment option (essentially at any, even advanced, age). Many people are able to return to nearly completely normal activity after recovering from the surgery. When considering joint replacement surgery, talk to your doctor about the benefits and risks.
Many cases of OA can be prevented. To prevent the development of OA later on in life, maintain a healthy weight. Excess weight can put stress on weight bearing joints such as knees or hips and increase the wear and tear on the cartilage. Protect your joints from injury. Repeated minor injuries due to constant kneeling, squatting, or other postures that place stress on the knee joint can cause cartilage to breakdown. Exercise can help reduce joint pain and stiffness. Talk to your physiotherapist or occupational therapist about how low-impact exercise such as bicycling, swimming, or water exercise could be beneficial for you.
Athletes should understand that OA later in life is common for people who have lived a very active and rigorous lifestyle.
For most, this risk is probably worth the value they receive from their athletic passion. They should be particularly careful to take immediate care of all injuries, even seemingly minor ones, and to closely follow their doctor's advice.
There is some limited evidence that shows the chiropractic treatments such as manipulative therapy combined with multimodal or exercise therapy can help alleviate pain in people who have hip or knee OA.