Osteoarthritis, or joint wear and tear, is not a single disease but the result of a disorder that leads to progressive structural degeneration of at least one joint.
Osteoarthritis is the most common cause of chronic joint pain, and it is estimated that more than 10% of the population is affected. Osteoarthritis affects the joint as a whole: ie the muscles that act there, the bones that make it up, the inner layer of the joint capsule (synovium), the intervertebral discs and, in the case of the knee , also the menisci.
The initial stage of arthrosis is characterized by the breakdown of the cartilage (cartilage tissue). The body attempts to repair the cartilage, reshaping the bone so that a compaction is formed at the interface of the cartilage (subchondral bone) and bone cysts form.
This is usually a gradual process that can be divided into different phases:
- As the disease progresses, bony outgrowths (osteophytes) form and the joint space (space between the bones) narrows.
- As the arthrosis progresses, the space between the joints becomes smaller and smaller.
- Later, subchondral cysts (cysts on the bone beneath the cartilage) appear.
- In the final phase of osteoarthritis, the bones are repaired and reshaped.
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Scientific terminology
As the most important protein, collagen is a component of tendons, bones, cartilage, connective tissue and skin.
The articular surface is the part of the joint where the ends of the bones meet.
Articular cartilage is a jelly-like and elastic layer of tissue on the articular surface that allows fluid and pain-free movement because friction is reduced.
The synovial membrane is a fibrous tissue surrounding a joint that releases a lubricating fluid to make movements smooth.
Osteophytes are bony prominences that tend to form on the outer edge of the joint.
They are thought to be formed to widen the bearing surface of the joint so that body weight and external forces can be distributed over a larger area.
Bone remodeling is a process in which damaged bone attempts to repair itself by changing shape and internal density.
What are the causes of osteoarthritis?
Primary arthrosis is a disease that does not arise as a result of trauma or a previous illness, but is the result of natural joint aging.
With age, the water content in the cartilage decreases and the collagen contained in the cartilage degenerates.
Over time, the cartilage layer thins and cracks form.
In the advanced stage of arthrosis, the articular cartilage is completely worn down.
Over the years, stress and use of worn joints can cause inflammation of the synovial membrane , producing pain and swelling. The loss of the cartilage buffer creates friction between the bones; the result is pain and restricted mobility of the joint. TheInflammation can also stimulate the formation of bony outgrowths (osteophytes, bony protuberances) at the joint. Arthrosis can occur in several family members, which speaks for a hereditary or genetic component.
Factors that increase the risk of osteoarthritis:
- Age: the risk of developing arthrosis increases with age.
- Gender: Women are more commonly affected, although the causes are unknown.
- Bone deformities: some people are born with misaligned joints or cartilage defects; This can increase the risk of osteoarthritis.
- Lesions, fractures , distortions as a result of trauma (e.g. during sports or an accident) are considered a risk of arthrosis.
- Obesity: a very heavy body puts a lot of pressure on the weight-bearing joints (e.g. knees).
- Sedentary life: Cartilage needs movement to be adequately supplied with nutrients.
- Certain Occupations: If you perform repetitive movements that overuse a joint, osteoarthritis is likely to develop at that point.
- Secondary diseases: Diabetes , hypothyroidism , gout and Paget’s disease can promote osteoarthritis.
Osteoarthritis usually progresses slowly and symptoms worsen over time.
The symptoms vary greatly from person to person. Some patients are practically disabled by the symptoms, while others experience only mild discomfort, although the x-ray shows dramatic degeneration of the joints.
The symptoms can also temporarily disappear again. It is not uncommon for patients with arthrosis in the hands or knees to remain pain-free for years between the individual joint inflammations.
Signs and symptoms of osteoarthritis
- Pain: Pain, stiffness , or mobility problems occur in at least one joint. The pain can increase with exertion and can also be felt at night. In an advanced stage, it can also occur during rest periods.
- Pressure pain: the joint hurts when light pressure is applied from the outside.
- Stiffness: the restriction of movement is particularly great in the morning after getting up and after a rest phase.
- Loss of flexibility: joint blockage can develop where normal range of motion is lost.
- Joint noise: it sounds like two rough surfaces rubbing against each other.
- Arthrosis of the spine (spondyloarthrosis) causes neck or back pain . The bony outgrowths (osteophytes) that may form along the spine affected by osteoarthritis can irritate the spinal nerves and cause serious symptoms such as pain radiating to the extremities, numbness and tingling sensations in the extremities.
Osteoarthritis promotes the formation of hard bony outgrowths in the small finger joints.
A classic case of this is the Heberden knot, which forms at the end joints of the fingers and is named after the famous English doctor.
Bone deformation is the result of osteoarthritis-related bone protrusions in the joint. Another bony knot that forms at the level of the middle joints of the fingers is called Bouchard’s knot.
If swelling and stiffness of the joints lasts longer than two weeks, a doctor should be consulted.
The doctor will examine the affected joint to see if there is tenderness, swelling, and redness.
Then he will assess the mobility of the joint.
Imaging diagnostic procedures
- X-ray examination : Cartilage is not visible on an X-ray, but narrowing of the joint space (space between the joint bones) can be seen.
An x-ray also shows bony outgrowths at the edge of the joint. Many people already have signs of osteoarthritis before they experience any symptoms. - Magnetic resonance imaging (MRI) uses radio waves and a magnetic field to show detailed images of bones and soft tissues, including cartilage. This method is helpful in determining which tissue is causing the pain.
laboratory tests
Blood tests can rule out other causes of joint pain, such as rheumatoid arthritis .
During an arthrocentesis, synovial fluid is removed and analyzed. This test will help determine whether the pain is due to infection or arthritis, such as gout .
