What is Osteoarthritis?

What causes Osteoarthritis?

Dispelling myths around the causes of Osteoarthritis

Which joints are affected in Osteoarthritis?

How are joints affected in Osteoarthritis?

What are the signs and symptoms of Osteoarthritis?

How is Osteoarthritis diagnosed?

Download our Living with Osteoarthritis booklet

What is osteoarthritis?

Osteoarthritis is a condition that usually develops gradually, over several years and affects a number of different joints. For some people, the changes are so subtle and develop over such a long period of time that they are hardly noticeable. Others however, may experience gradually worsening problems, including pain and restricted movement, particularly in large joints such as the hip or knee. You may have to see the doctor from time to time to discuss your condition and your treatment.

We do not yet know the causes or the cure for osteoarthritis.

Although there is a connection with the ageing process, doctors and researchers are trying to identify what factors in this process trigger the disease. The last decade has seen significant advances in understanding the processes that contribute to osteoarthritis and over the next decade, these new insights will hopefully lead to better treatments.

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What causes osteoarthritis?

There is no single trigger identified that causes osteoarthritis, however, there are definite risk factors.

Age

People usually develop osteoarthritis after 40 years of age through to old age and it is often undiagnosed. Although it is uncommon before the age of 40, young people can develop it.

The reason for OA affecting older people isn't precisely known, however, degeneration in the quality of cartilage or joint fluid might be a factor relating to age. Impaired healing related to age might also contribute whereby small injuries to the joint structures trigger a degenerative process. Reduced strength in the muscles surrounding affected joints might also be related to age, for example, a weakened thigh muscle (quadriceps) can contribute to knee OA.

Genetics/Heredity

One common form of osteoarthritis – nodal osteoarthritis – runs strongly in families. This particularly affects the hands of middle-aged women. In other common forms of osteoarthritis, heredity plays a small part compared with obesity, ageing and joint injury.

There are some very rare forms of osteoarthritis that start at a young age and run in families and these are linked with single genes that affect collagen – an essential component of cartilage.

While traditionally OA has been referred to by health professionals and lay people as "wear and tear", this description is now felt to be inaccurate  Studies of people who have led very similar lives show some will have virtually perfect joints, while others have quite severe osteoarthritis. Therefore, it seems there must be an inbuilt susceptibility to, or protection against, osteoarthritis.

Gender

Osteoarthritis is more common and often more severe in women, especially in the knees and hands. It often starts after the menopause.

Obesity

Being overweight is a significant risk factor for developing OA, particularly in the knee and hip, but also the hands. It is thought that excess fatty tissue in the body creates an environment that has a toxic effect on the small joints of the hand.

Joint injury

A major injury or operation on a joint may lead to osteoarthritis at that site later in life.

Normal activity and exercise are good for the joints and do not cause osteoarthritis. However, very hard, repetitive activity may injure joints. Exercising too soon after an injury has had time to heal properly may also lead to osteoarthritis in that joint later on. It is always best to check with your doctor, physiotherapist or nurse when it is safe to exercise after you have sustained an injury.

Joint Alignment

The alignment of the bones making up the joints can be a cause for developing OA in affected joints later in life. This is commonly seen in the knee where someone is "knock-kneed" (valgus alignment) or "bow-legged" (varus alignment).

Occupation

Certain occupations can place excessive loads on the joints resulting in OA in later years. Jobs with repetitive knee bending can result in knee OA, while heavy manual labour might predispose to hip OA.

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Dispelling myths around causes of osteoarthritis

Osteoarthritis does have other causes that we don’t know about yet, but we do know enough to correct some myths. Although there is no evidence to support the claim that weather makes arthritis worse, many people find that their joints often tend to feel worse when the atmospheric pressure is falling, for example, just before it rains.

However, although the weather may temporarily affect symptoms, it does not cause arthritis. Warmer regions in the world do not have lower incidences of arthritis than colder regions. Osteoarthritis occurs all over the world, in all types of climate.

While some types of arthritis – gout for example – are directly affected by diet, there is no evidence that a particular diet will eliminate the condition. However, some people claim certain foods make their pain or inflammation worse. It is very important to keep your weight as close as possible to the ideal for your height and age. Excess weight compounds the problem by putting extra strain on damaged joints. It is also important to eat a balanced diet to nourish muscles, cartilage and bone. This will reduce the risk of osteoarthritis.

One of the biggest myths is that exercise is bad for your joints. Numerous studies have shown that exercise is a better reliever of pain than commonly used painkillers in knee OA. Exercise has been shown to improve the health of joint fluid and also strengthens supporting muscles around arthritic joints. However, the type of exercise undertaken is key.

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Which joints are affected in osteoarthritis?

The spine and weight-bearing joints such as the knees, ankles, hips and spine are most frequently affected by osteoarthritis, making mobility difficult.

Pain can vary in severity and can be so mild that many people don’t even notice it, or so severe that mobility and quality of life is affected. Osteoarthritis in the fingers, thumbs and wrists affects grip strength and the ability to perform everyday tasks such as opening jars, picking small things up, writing and doing up buttons.

Shoulder and elbow joints are also susceptible to arthritis although this is much rarer. Some people may experience a grinding feeling in the shoulder and a reduced range of movement. Elbows are very sensitive to injury so very mild arthritis here can lead to quite a significant loss of mobility.

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What happens in a joint with osteoarthritis?

Healthy cartilage – the protective layer that covers the bone end in the joint – is very smooth, strong and flexible. It absorbs the stresses put on a joint and allows the bones to move smoothly over each other.

In osteoarthritis, this becomes pitted, brittle and thin, and, over time, can wear out completely. When the cartilage deteriorates, the bone underneath thickens and broadens out.

Over time, the joint fluid, which functions as a lubricant, can deteriorate in quality.  The joint lining (synovial membrane) that makes the joint fluid can become inflamed and swollen. 

These processes, combined with thinning cartilage, affect the smooth movement of the joint, and contribute to pain, stiffness and joint swelling. Bony spurs can develop around the joint, causing it to change shape and appear knobbly.

At the same time, the joint capsule becomes thicker and the amount of synovial (lubricating) fluid can increase, often causing the joint to swell. It may also become stiff and painful to move.

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What are the signs and symptoms of osteoarthritis?

The early signs of osteoarthritis are so mild that they are often easy to miss. The main symptoms are stiff and painful joints, with the pain tending to be worse while exercising the joint and at the end of the day. Stiffness usually wears off after resting, but the joint may not move as freely or as far as normal and may ‘creak’ or ‘crack’ when moved.

Muscle strengthening exercises can prevent the joint giving way. Symptoms can vary and you may have bad patches of a few weeks or months followed by better periods. You may find that it depends on how much physical activity you do. Joints may appear swollen. In more advanced cases, there may be constant pain and everyday tasks and movement may become difficult.

It is important you visit your GP and don’t ignore your symptoms, as early diagnosis may help prevent unnecessary damage.

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How is osteoarthritis diagnosed?

Your GP will be able to assess whether you have osteoarthritis or whether your symptoms are due to another illness.

Your history

Your GP will begin by asking you to describe the symptoms, and when and how the condition started. Make sure you tell your doctor exactly how you feel, giving a good description of pain, stiffness and joint function, how they have changed over time and how your work and daily life are affected. Finally, you will be asked about any other medical conditions you may have and whether you are taking any medicines.

Physical examination

Your doctor will examine your joints and may check muscles, nerves and aspects of your general health, feeling for any bony swellings and creaking joints. They will also look for any restricted movement, joint tenderness and any thinning muscle, excess fluid or instability in the joints. You may be referred, after a time, to a physiotherapist or occupational therapist who can give you special exercises to do and advice on how to relax, overcome mobility problems avoid joint strain and cope with pain.

If your arthritis is severe, you may be referred to a hospital specialist such as a rheumatologist or an orthopaedic surgeon.

Testing for osteoarthritis

There is no blood test for osteoarthritis although you may be given one to rule out other types of arthritis. X-rays are often used to confirm that OA is the cause of pain in a joint(s). X-ray changes due to OA include bony growths/spurs called "osteophytes", bone thickening beneath the cartilage layers and give an indirect view of how much cartilage "wear" has taken place. X-rays do not determine how much your arthritis will trouble you, an X-ray that shows severe changes does not necessarily mean that you will have a lot of pain or disability. Also, they may not show early osteoarthritis damage.

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Looking after your joints

Most people can lead a full, active life with osteoarthritis by properly managing the condition and making small, common sense alterations to life. There are many things that can be done to help alleviate the symptoms and prevent the disease from progressing. Regular exercise, protecting the joints from further injury and maintaining an ideal weight through a healthy diet will all benefit you.

Inflamed or damaged joints need to be cared for and protected. Keeping healthy is part of this, but you also need to avoid straining joints by overdoing things or doing them awkwardly. You may have to give more thought to the clothes and shoes you wear, to the way you lift, grip and carry things or to the way you arrange your home or place of work. An occupational therapist can help with all of this.

Download our Living with Osteoarthritis booklet

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For more detailed information about osteoarthritis and sleep & fatigue, exercise, work and lifestyle information, contact the Arthritis Ireland Helpline 1890252846/01-6618188 [email protected] 

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