Joint problems become more common as we get older. It is not necessarily a natural part of aging. Some joint problems are diseases that afflict only a few people and could be prevented at times. If you suspect that your joints are getting worn out with age, then you should keep an eye on the signs of joint wear and tear. The joints are simply the site where two bones in the body meet. Most joints are designed in a way that the end of each bone in the joint can move thereby allowing the associated body part to move. Joints allow for mobility and give us the flexibility that we have. If the two ends of the bones had to rub against each other then movement would neither be smooth nor sustainable.
Cartilage and synovial fluid
The body has two ways to overcome the possibility of bone rubbing against bone. First is the fluid in the joint space – synovial fluid. The second is the smooth connective tissue that caps the end of the bones – articular cartilage.
In this way it is the articular cartilage at either end that rub against each other. But this friction is minimal as the joint is encapsulated with a lubricating fluid (synovial fluid) surrounding the articulating ends of the bone. Cartilage also has the ability to regenerate very rapidly which is important for its function.
So even though the cartilage is being constantly worn during the course of everyday movement, it is just as rapidly being replaced. But this balance can sometimes be disturbed. With age the regenerative capacity of the cartilage decreases. Furthermore, excessive strain or overuse of the joint may wear down the cartilage faster than it can be replaced.
As the cartilage wears down, a condition known as osteoarthritis develops. Osteoarthritis is therefore known as a degenerative joint disorder. If the cartilage wears out entirely, the ends of bone may eventually start grating against each other. It does not happen overnight. Osteoarthritis develops over years and decades and is the most common type of arthritis.
It affects more than 50% of people older than 65 years and by 75 years almost every senior will develop some degree of osteoarthritis. But it can occur earlier in life, especially if you are very active, obese or sustain a severe injury to the joint. All of these factors results in strain on the joint cartilage. Genetics and certain medical conditions may also speed up the onset of osteoarthritis.
Most affected joints
The joints that are more likely to be affected by degeneration of articular cartilage are the larger joints in the body that bear more force in the course of life.The knee, hip and shoulder joint are therefore the main joints involved but it is possible for any other synovial joint to be affected in osteoarthritis. Remember that osteoarthritis is different from rheumatoid arthritis, not only in the disease process, but also in the joints that are more likely to be affected.
- Osteoarthritis affects larger joints while rheumatoid arthritis typically involves the smaller joints like that of the fingers.
- Osteoarthritis may affect one joint only at times while rheumatoid arthritis affects the joints on both sides of the body.
- Osteoarthritis primarily involves the cartilage of the joints while rheumatoid arthritis tends to mainly affect the joint linings.
Pain in the joints
Pain in the joints (arthralgia) are a common symptom. But it may not be one of the first symptoms that appear. In the early stages of osteoarthritis, pain is an unreliable indicator of the severity of the condition especially since it may be absent in some cases. Osteoarthritis is not an inflammatory joint condition like rheumatoid arthritis so pain may not be as prominent at the outset. But the friction between the two ends of the bone can injure the bone itself or the associated parts of the joint. The pain tends to start during physical activity or even after it and may persist for several minutes, hours or even days after strenuous activity.
Tenderness of the joints
Even if pain is not evident there may be some degree of tenderness of the joint. Applying light pressure on the joint with your hands may reveal the tenderness or you can experience it when placing pressure on the joint like while kneeling if the knee is affected. Tenderness of the joint is one of the first symptoms. As with pain, it may be worse during and after movement. Tenderness can persist for prolonged periods even after resting your joints. It worsens as the condition progresses and can make the use of a brace difficult.
Stiffening of the joints
Since the articular cartilage is the main part of the joint that keeps it mobile, a breakdown of this cartilage eventually leads to stiffness of the joints. It tends to be worse when you are inactive for a long period, like after waking up in the morning or sitting and watching TV for hours at a time. The stiffness tends to ease as a person moves the joint slowly but excessive movement will then bring on pain. It is therefore important that a person with osteoarthritis maintains a balance in their daily activities and not be underactive nor overactive.
Less joint flexibility
Even without pain and stiffness, you may find that joints are not able to maintain its normal flexibility. In other words you cannot bend to the same degree that you could in the past. The range of motion diminishes gradually and is often passed off as a consequence of aging. But it may in fact be the degeneration of your joint cartilage. Remember that your muscles are also play a central role in flexibility and mobility so it is important to differentiate between a joint cartilage problem and a muscle problem. Fusion of the bones with almost complete loss of flexibility is a late complication.
Grating sound or feeling
The articular cartilage is smooth and coupled with the lubrication provided by the synovial fluid, joint movement is almost silent. But as the cartilage erodes and becomes rough, there may be some sound emanating from the problem joint. In the early stages there may be no sound but you may be able to feel a grating sensation when you move the joint. Eventually the cartilage will be worn down entirely or portions of it may break into the joint space. This allows the synovial fluid to seep into the bone itself. The bony ends in the joint become rough and when it rubs against each other, the grating sound is audible even to others in close proximity.
Bony lumps in the joint
Over time the exposed bone without the protection of the articular cartilage becomes affected in various ways. It cracks, bits break off, synovial fluid seeps into the bony ends and reformation of new bone is abnormal. Outgrowths from the bone, often referred to as bony spurs, may develop on the ends of the bone in the joint. This affects normal joint movement in even further. The bony spurs may be felt as lumps on the skin over the joint. It may even be visible as small bumps in some instances. This is a late complication of osteoarthritis and may not always be evident in every case.
Article reviewed by Dr. Greg. Last updated on June 19, 2013