Features of osteoarthritis on examination
Features of Osteoarthritis are divided into symptoms - what the person is complaining of, and signs - what the examiner can find.
Pain is the most common complaint and the thing which brings people to a doctor. It’s intensity and nature is described in hugely variable ways by different patients but it usually comes on gradually, is mild or moderate in level, is made worse by activity and improved by rest.
Activity pain usually begins soon after the activity itself and may continue for hours after the activity ceases. Many people complain of a vague ache or pain during activity while others describe sharp or stabbing pains associated with a particular activity.
If Osteoarthritis is severe there may be pain at rest (50% of sufferers or less) and at night (around 30% of sufferers). Severe and progressive osteoarthritis occurs at times, with a severely painful joint and significant disability.
Pain in joints with osteoarthritis could come from the membrane lining the joint, the joint capsule (fibrous bag around the joint), the ligaments around the joint, from muscle spasm and the underlying bone. Osteoarthritic joints are often tender at points around the margins and very sore if knocked or injured in any way.
However, pain in osteoarthritis is not simply related to the changes in the joint or surrounding tissues but is influenced by many factors. Although pain complaints fit well with x-ray changes of OA, the severity of pain does not reflect the severity of the changes. This means someone may have significant OA changes on x-ray but complain of little pain, while someone else may have little evidence of joint changes on x-ray but complains of severe pain.
Most people with an arthritic joint complain of stiffness at some times, either in the morning or on movement. Stiffness is hard to define clearly but we all know it when we get it. It seems to be either difficulty in getting a joint moving again after it has been still for a while, or a feeling of resistance as the joint is moved through its range.
A joint may have to be loosened up in the morning for a few minutes to half an hour. Longer periods of stiffness, or widespread stiffness through the body, is more characteristic of the arthritic diseases, the most common of which is rheumatoid arthritis.
Loss of joint movement
Joints often lose some of their range of movement when affected by osteoarthritis, with the ends of the movement reduced. Pain is often present when the joint reaches the end of its limited range. The reasons for this may be various: a thickening and tightening of the fibrous bag surrounding the joint, remodelling of the joint as the cartilage thins and the underlying bone becomes denser and bony outgrowths at the margins of the joint (osteophytes).
Giving way of a leg is a common complaint with OA of the knee or hip, with a feeling of insecurity, as if the leg cannot be trusted at times to support the weight of the body. There may be no actual signs of the joint being unstable but often there is weakness with muscle wasting. It may be that the muscles are weak or poorly co-ordinated as so the leg feels less trustworthy at times.
Osteoarthritis joints may have enlarged areas around them, which seem to be bony in nature in that they feel very firm and also tender. They may be made up of a mixture of soft tissue, cartilage and bony outgrowths.
Swelling and inflammation
Apart from firm swellings, there may be soft swelling (e.g. “water on the knee”) in OA joints, which is quite different to the harder swelling described above. In this case the cause of the swelling is not well understood, but it is composed to synovial fluid, an overproduction of the natural lubricating joint fluid. OA joints may feel warm at these times, and this may be due to a low grade inflammation occurring, with periods where the inflammation is more obvious with joint warmth and redness. These increased inflammatory symptoms may occur during flare ups of the joint pain and problems, typically lasting for a few weeks.
When osteoarthritis gets severe it may be obvious that there is severe damage and destruction to the joints involved. As wear progresses in some joints, they may alter shape and become deformed. Examples are bow-leg and knock-knee in the knee joint, shortening of the leg in hip disease and the deformity and instability (wobbliness) which can occur in the end joints of the fingers.
Functional loss and handicap
Osteoarthritis causes a great burden to millions of people trying to live their lives in the world. Functional loss can be caused by pain, loss of movement or a decrease in muscle power. This can lead to disability, for example difficulty reaching the feet to dry them or put on socks, limited walking distances and problems with stairs. This in turn can lead to handicap, which is related more to the loss of independence, loss of role and depression which many people suffer.
Creaking and crunching
In osteoarthritis, patients often complain of crunching and cracking in their joints (technically called crepitus). A joint may give out loud cracks and crunches if the arthritis is severe. These noises may be due to the roughening and abnormality of the joint surfaces.
Diagnosing osteoarthritis is often confirmed by the changes seen on x-ray - bony outgrowths at the joint margins, narrowing of the ‘joint space’ where the cartilage has worn down, increased density of the bone underlying the cartilage, cyst formation in the underlying bone and sometimes obvious deformity of the joint. Blood tests are usually normal.
Over time, the usual pattern of OA is for the x-ray changes to progress gradually, but in some people the picture may not change over long periods. Pain may improve, but function of the joint less commonly does.