Osteoarthritis (OA) is a joint disease affecting the entire joint, including the cartilage, bones and joint lining.
Lifestyle factors, age, joint damage and genetics can all contribute to osteoarthritis and cause the breakdown of cartilage in the joints.
This can lead to inflammation and changes in bones and joint tissues. People may experience joint pain, stiffness, and reduced range of motion.
This article examines the changes that occur in osteoarthritis and how these cause symptoms.
Osteoarthritis is a disease of the whole joint, which includes:
- fat pads
- lining of the joint, called synovium
In osteoarthritis, the cartilage breaks down, leading to changes in bone and joint tissue. Along with inflammation, this can cause pain, stiffness, and loss of flexibility.
Osteoarthritis can occur in any joint, but most commonly affects the knees, hips, lower back, neck and hands.
Symptoms of osteoarthritis can come on gradually and can include:
- articular pain
- stiffness, often first thing in the morning or after rest
- reduced range of motion, which may improve with movement
- weakness in the muscles surrounding an affected joint
- loss of balance or unsteadiness
- popping or clicking noises when a joint moves
Osteoarthritis causes inflammation, changes in the shape of bones and deterioration of cartilage. It is mainly a disease affecting the cartilage.
Osteoarthritis occurs due to a combination of factors,
- physical stress on the body, such as general wear and tear
- physical changes that affect joint function, which may be present from birth or may develop due to excess weight putting pressure on the joint or injury
- other risk factors, such as aging or genetics
People with the disease have higher levels of pro-inflammatory markers, which indicate inflammation, and proteases, which are enzymes that break down proteins. These eventually lead to joint deterioration.
In most cases, the first changes that occur in the body due to arthrosis affect the articular cartilage. It is the cartilage covering the ends of the bones where they meet at the joint.
Articular cartilage may erode or become irregular, split or frayed. If there are erosions in the cartilage, these can gradually extend down to the bone level and further affect the joint surface.
Cartilage is made up of water and the matrix, which is a gel-like substance containing different types of proteins:
- non-collagenous proteins
Articular cartilage contains a group of cells called chondrocytes, which produce and maintain the matrix.
Injury or damage to cartilage
Matrix damage can also cause thickening of the bone under the cartilage and can sometimes cause fluid-filled areas in the bone called bone cysts.
Along with these cartilage changes, there may be inflammation of the synovium of the joint.
These changes may happen gradually, and people may slowly begin to experience symptoms of osteoarthritis, such as pain, stiffness, and limited range of motion.
Learn more about cartilage damage.
Certain risk factors can increase the likelihood of osteoarthritis. These include:
- Age: People over 50 may be more susceptible to osteoarthritis, as the risk increases with age.
- Joint injury: An injury to the joint area, such as a bone fracture or a tear in the cartilage or ligament, can lead to osteoarthritis.
- Overuse: Repetitive use of the same joint, for example in a sport or occupation, can lead to osteoarthritis.
- Obesity: Excess weight puts additional stress and strain on the joints, and fat cells can increase inflammation.
- Musculoskeletal Abnormalities: Improper alignment of bones or joints can increase the risk of osteoarthritis.
- Weak muscles: If the muscles cannot properly support the joints, it can lead to improper alignment and osteoarthritis.
- Genetic: People who have a close family member with osteoarthritis are more likely to develop the condition themselves.
- Genre: Osteoarthritis is more likely to affect women than men.
- Environmental factors: This includes factors such as level of physical activity, occupation, diet, sex hormones and bone density.
Complications of osteoarthritis can include:
- difficulty walking
- misalignment of joints
- reduced range of motion
- pinched nerves in the spine
- side effects of painkillers, such as dizziness
According to the Arthritis Foundation (AF), people with osteoarthritis have an increased risk of falling, which, in turn, increases the risk of fractures.
This increased risk is because osteoarthritis, especially osteoarthritis of the knees or hips, can affect balance, weaken muscles and reduce joint function.
If osteoarthritis medications cause dizziness, this may also increase the risk of falls.
The FA also indicates that weight gain may occur in people with osteoarthritis if joint pain causes difficulty in exercising. Carrying excess weight can lead to various health problems, such as:
If people are concerned about complications from osteoarthritis, they can speak with a healthcare professional to minimize the risks. The healthcare professional may recommend lifestyle changes, exercise programs, and assistive devices to improve stability.
The following conditions
- Rheumatoid arthritis (RA): Rheumatoid arthritis is an autoimmune disease that causes inflammation of the joints. It can cause pain and stiffness,
usuallyin the hands, wrists or knees.
- Psoriatic arthritis (PR): PSA is a type of arthritis that often affects people with psoriasis. This can cause swollen and painful joints.
- Crystalline arthritis: It happens when deposits of crystals, such as uric acid or calcium, rub against the joints.
- Bursitis: Bursitis is the term for inflammation of the bursae, which are fluid-filled sacs that cushion the joints.
- Tendonitis: Tendonitis is an inflammation of a tendon, the tissue that connects muscle to bone.
- Excess iron: If excess iron builds up in the body, it can cause joint pain,
above allin the hands and knees.
- Vascular necrosis: A lack of blood supply to the bone can lead to the death of bone tissue.
- Radiculopathy: Radiculopathy is a pinched nerve in the spine, which can cause pain, weakness, tingling, or numbness.
Learn more about possible causes of joint pain.
The outlook for people with osteoarthritis
Some people may find that osteoarthritis has little effect on their daily life, while others may have more serious symptoms that affect their ability to perform daily tasks.
Treatments can help people manage the symptoms of osteoarthritis. In some cases, joint replacement surgery may provide the best long-term outcome for someone with osteoarthritis.
Osteoarthritis occurs when the cartilage in the joints breaks down, leading to changes in bone and joint tissue. Symptoms include pain, stiffness and reduced mobility.
Various risk factors, such as age and genetics, can combine to cause the production of pro-inflammatory markers and proteases, which ultimately lead to joint deterioration.
Exercise, medication, and in some cases surgery can help manage osteoarthritis symptoms and minimize further joint damage.