Osteoarthritis (OA) is a disease that primarily affects the cartilage lining of the joints and the bones associated with the joints, the subchondral bones. Osteoarthritis is one of the most common forms of arthritis
However, all the tissues surrounding the affected joint eventually become abnormal. The cartilage lining the joint frays and outgrowths of bone form around the joint in an attempt at healing. Fragments of this bone break off and irritate the joints, which lose their natural lubrication and become stiff and noisy.
Osteoarthritis used to be seen as a result of wear and tear of the joints. In fact, the disease is now thought to have several subtypes, of which some are more aggressive and related to immune mechanisms, resulting in inflammation and erosion of the cartilage and adjacent bone – called erosive osteoarthritis.
The mechanism is a complex system of interacting mechanical, biological, biochemical and enzymatic feedback loops. In short, joints are complex things whose healthy function relies on a variety of things – when one or more of these things fail or are absent, osteoarthritis occurs. Anything that changes the micro-environment of the bone cell may initiate the chain of events which leads to osteoarthritis – congenital joint abnormalities, genetic defects, infectious processes, metabolic processes and disease. Trauma to a joint may initiate osteoarthritis, including prolonged overuse of a joint or group of joints.
Osteoarthritis has a tendency to be a genetically primed disease, especially in the end joints of the fingers and the spine.
Who gets it and who is at risk?
Osteoarthritis is the most common of all joint disorders. The first symptoms appear usually in the 4th decade and 60-70% of people are affected by the 7th decade.
Early on, more women than men are affected, but this is less marked in the elderly. There is a strong hereditary tendency, especially when hand joints are involved in women. There is evidence that genes coding for collagen components within cartilage may be abnormal, explaining the family clustering of this condition.
The earlier the onset and the greater the genetic factors, the greater the risks of developing osteoarthritis. Patients who have both parents affected will most certainly develop osteoarthritis.
Obesity is an independent risk factor for osteoarthritis of the knee, and may predict development of the condition 30 years later. Although mechanical loading is the obvious explanation for this link, other metabolic abnormalities associated with obesity may be at play.
Joint hypermobility is also an independent risk for development of OA. Some patients may have extreme hypermobility, leading to recurrent stress injuries and early OA of weight bearing joints.
Symptoms and signs
The joints most commonly affected are the neck, hips, knees, back and small joints of the fingers.
Initially osteoarthritis may be associated with an inflammatory process and the onset is seen with mild swelling and stiffness in the hands and affected joints. It is usually subtle and gradual. Pain is the earliest symptom, made worse by exercise. The stiffness is short-lived, and usually occurs in the morning (less than 30 minutes) and may recur after periods of sitting or inactivity. It usually improves with exercise.
As the disease progresses, motion of the joints is decreased and the person may notice tenderness and grinding noises in the joint. The joint eventually enlarges from bony outgrowth. The bony enlargement is irreversible.
If the ligaments become lax, for example around the knee, the joint has increased instability with more pain. Tenderness to the touch and pain when the doctor moves the joint are signs of advanced disease. At this stage muscle spasm and contraction of the muscles around the joints add to the pain.
Osteoarthritis of the hip is characterized by increasing stiffness and loss of range of motion. The patient may experience difficulty in climbing stairs or tying his/her shoelaces. This is in contrast to osteoarthritis of the knee in which the ligaments tend to become lax.
How is osteoarthritis diagnosed?
Diagnosis is usually based on symptoms, signs and X-ray changes. Blood studies are used mainly to rule out other causes of arthritis. X-rays may be normal early on, but are characteristic in later disease. Therefore a clinical examination and X-rays are the most important aspect of the diagnosis – not the blood tests.
Can it be prevented?
You may be able to prevent your risk of developing osteoarthritis by:
- Protecting an injured joint from further damage. If you experience persistent pain in a joint, we recommend you consult a health professional for a proper diagnosis.
- Exercising moderately for 30 minutes 5 times a week and maintaining a healthy weight. Exercise that places constant, heavy pressure on the joints should be avoided.
- Avoiding repetitive motion, particularly if under strain / against resistance.
How is it treated?
Diet and natural supplements
- Glucosamine is critical to joint health. It supports joint health, joint resilience and can help reduce wear and tear on the joints. It can also help improve joint function, reducing pain and inflammation in the joint. Studies have shown increased intake of glucosamine over time is effective at relieving symptoms in osteoarthritis sufferers with severe symptoms. Glucosamine may take up to 2 months to provide noticeable benefit, but many notice results sooner.
- Chondroitin supplements may also help support better joint health. Arthritis Victoria states that several studies have found a positive correlation between increasing chondroitin intake and both a reduction in joint pain and a reduction in the rate of joint deterioration.
- Omega-3 fatty acids have many health benefits, including anti-inflammatory properties. High doses of fish oil can help reduce the inflammation and joint immobility of arthritis sufferers. Increasingly popular in the treatment of temporary symptoms of mild osteoarthritis is krill oil, which is rich in EPA (a type of omega-3). Krill oil contains phospholipids, water soluble molecules that are thought to make the omega-3 easily absorbed.
- Other studies show that SAMe (s-adenosyl-L-methionine) and MSM (methylsulfonylmethane) can be effective in reducing the symptoms of arthritis. Many omega-3 supplements are fortified with these nutrients to reduce the number of tablets you take in a day to support joint health.
- There is some evidence that deficiency in vitamin D3 may increase the risk of some forms of arthritis. Vitamin D3 is usually received through direct sunlight on the skin, but supplements are also available.
- Try to eliminate saturated fats and processed foods from your diet. Introducing more fresh fruit and vegetables, and ensuring adequate lean meat intake (tofu and nuts are a good option for vegetarians) will help fight inflammation and the associated joint pain suffered by those with arthritis.
- Some nutritionists recommend the use of ginger to help support reduction in joint inflammation and pain.
In spite of pain, it is important to keep active. Exercise maintains range of motion, and develops the stress-absorbing muscles and tendons. Daily stretching exercises are very important. Partial or complete immobilisation of a joint for relatively short periods can accelerate osteoarthritis and worsen the clinical outcome.
Progression of osteoarthritis of the hips and knees can be retarded by a well-planned exercise regime.
These are divided into symptomatic and disease-modifying therapies. Symptomatic therapies include painkillers such as paracetamol, and paracetamol/codeine preparations or even stronger opiate type drugs. These drugs are very safe and may provide sufficient relief.
Anti-inflammatories, which treat inflammation and pain, include aspirin and other non-steroidal anti-inflammatory drugs. These are potentially hazardous to the stomach. Newer safer drugs called COXIBs are available, which are less damaging to the lining of the stomach. Cardiovascular safety of these drugs is, however, still under scrutiny and they should be used with caution in those with heart disease, high blood pressure or who have had a stroke.
Oral cortisone is not helpful in osteoarthritis, but cortisone injections into the joint are useful when there are signs of inflammation. However, these are usually only needed occasionally.
There is some evidence that glucosamine sulphate has a role to play in pain and stiffness management. It is made from shrimp and crab shells and can therefore not be used if the patient has seafood allergy. Chondroitin sulphate (made from bovine cartilage) may add some small further benefit.
Drugs such as antimalarials, tetracyclines and metalloproteinase inhibitors are in trials for disease modification in osteoarthritis.
Hyaluronan injections are lubricants similar to joint fluid, made from rooster comb. These are expensive and not proven to work. They are therefore not currently recommended for widespread use.
Surgery for damaged joints is very successful, with hip and knee replacements now commonplace operations. Hip replacement restores mobility and relieves pain in at least 95 % of cases. Hip replacements last for at least 10-15 years.
Other joints, such as the small joints of the fingers and even the shoulder joint are also being replaced with increasing success. A particularly successful operation can be performed for advanced osteoarthritis at the base of the thumb. An expert hand surgeon is able to craft an alternative joint surface using the patient’s own tissues.
Indications for surgery are joint pain that is non-responsive to medical therapy, or functional impairment. Age alone is not a contra-indication to surgery, but joint replacement is usually deferred in younger patients where possible.
With the correct approach of remaining active and keeping a check on weight, osteoarthritis need not become a disabling condition. However, the damage to the joints usually starts before symptoms arise, making it difficult to act early.
Consult your doctor if:
- A joint is becoming increasingly painful and swollen.
- You experience sudden extreme pain or immobility in a joint.
- You have experienced pain and swelling in your knee(s) and it now starts to give way on movement, particularly when going up and down stairs.
- You know that you have osteoarthritis of your weight-bearing joints, are overweight and would like some advice on weight loss and exercise.
- When you are no longer able to cope and suspect you need replacement surgery.
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