Knee anatomy, pain & treatment
Knee anatomy
The knee is the largest and most complex joint in your body. It is also the most common joint to be stressed and/or affected by arthritis. It is a hinge joint that allows your leg to extend and bend back and forth with minimal side-to-side motion. It is made up of bones, cartilage, ligaments, tendons and other tissue. The knee joins together the thigh bone, shin bone, fibula, and knee cap. Where the ends of the three bones touch is covered with articular cartilage, a smooth slippery substance that protects and cushions the bones as you bend and straighten your knee. Two wedge-shaped pieces of cartilage called meniscus act as shock absorbers between your thigh bone and shin bone. They are tough and rubbery to help cushion the joint and keep it stable. In addition, ligaments connect the knee bones and provide stability to the knee.
What causes knee pain?
Osteoarthritis of the Knee I Rheumatoid Arthritis
Knee pain can be caused by arthritis, injuries or other issues. If your knee pain is reoccurring, and you have not had an injury, the most likely reasons are osteoarthritis or rheumatoid arthritis. The main difference between osteoarthritis and rheumatoid arthritis is as follows: osteoarthritis (OA) is caused by mechanical wear and tear on joints, and rheumatoid arthritis (RA) is an autoimmune disease in which the body's own immune system attacks the body's joints. A medical professional should help diagnose either of these conditions.
Osteoarthritis of the knee
Most common symptom: pain around the knee joint
Sometimes called wear and tear arthritis, osteoarthritis is a common condition that many people develop after the age of 50, although it can occur at an earlier age, or after trauma to the joint. It can occur in any joint of the body but most often develops in weight-bearing joints, such as the knee.
What causes knee osteoarthritis?
In osteoarthritis, the injured cartilage in the knee joint gradually wears away over time. As the cartilage wears away, it becomes frayed and rough and the protective joint space between the bones decreases. This can result in bone rubbing on bone. To make up for the lost cartilage, the damaged bones may start to grow outward and form bone spurs or osteophytes.
What are the symptoms of knee osteoarthritis?
Osteoarthritis of the knee causes pain and stiffness. It can make it hard to do everyday activities, like bending over to tie a shoe, rising from a chair, or taking a short walk. Because osteoarthritis gradually worsens over time, the sooner you start treatment, the more likely it is you can lessen its impact on your life. Although there is no cure for osteoarthritis there are many treatment options to help you manage pain and stay active.
How to diagnose knee osteoarthritis
A medical professional can help diagnose knee osteoarthritis by giving you a physical exam, looking into your family history, and ordering x-rays and blood tests. Additional tests may be needed such as an ultrasound, MRI or bone scan.
How to treat knee osteoarthritis
Knee osteoarthritis cannot be reversed, but there are treatments that may help reduce pain. Physical therapy, acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), steroids, or a combination of these may be used as a treatment. If these do not help or pain, swelling and/or immobility worsen, surgery may be an option.
Risk factors that may make you more likely to develop osteoarthritis
Increasing age
Family history of osteoarthritis
Previous injury or trauma to the knee joint
Obesity/excess weight
Even if you do not have any of the risk factors listed above you can still develop osteoarthritis.
Rheumatoid Arthritis
Most common symptom: pain, stiffness, or swelling in the knees
Although rheumatoid arthritis most commonly affects the joints of the hands and wrists, it can also affect hips, knees, and shoulders. Women are two to three times more likely to be affected by rheumatoid arthritis than men.
What causes knee RA?
Rheumatoid arthritis is an autoimmune disease that causes your immune system to attack your own body’s cartilage and bone. As a result, the synovium thickens, swells, and produces chemical substances that attack and destroy the articular cartilage covering the bone. Rheumatoid arthritis often involves the same joint on both sides of the body, so both knees may be affected.
What are the symptoms of knee RA?
Knee RA can cause pain, stiffness, or swelling of one or both knees. Other symptoms may include fatigue, pain, loss of appetite, and stiffness in other joints.
How to diagnose knee RA?
A medical professional can help diagnose knee RA by giving you a physical exam, looking into your family history, and ordering x-rays and blood tests. Additional tests may be needed such as an ultrasound, MRI, or bone scan.
How to treat knee RA?
Knee RA may be treated with disease-modifying anti-rheumatic drugs (DMARDs), non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, or a combination of the three. If these do not help or pain, swelling and/or immobility worsen, surgery may be an option.
Risk factors that may make you more likely to develop rheumatoid arthritis
Gender: females are more likely to develop RA
Other auto-immune diseases, such as Lupus
24% of all adults have arthritis
-CDC, 2021
