Osteoarthritis (OA) of the Knee is one the most common knee joint disorder, which is due to aging and wear and tear on the knee joint.
Causes, incidence, and risk factors
Osteoarthritis of the knee is a normal result of aging. It is also caused by constant ‘wear and tear’ on the knee joint.
- Cartilage is the firm, rubbery tissue that cushions your bones at the joints, and allows bones to glide over one another.
- If the cartilage breaks down and wears away, the bones rub together. This causes pain, swelling, and stiffness around your knee.
- Bony spurs or extra bone may form around the knee joint. The ligaments and muscles around the knee joint become weaker and stiffer which cause discomfort.
Often, the cause of Osteoarthritis of the knee is unknown. It is mainly related to aging.
The symptoms of Osteoarthritis of the knee usually appear in middle age. Almost everyone has some symptoms by age 70. However, these symptoms may be minor.
Before age 55, Osteoarthritis of the knee occurs equally in men and women. After age 55, it is more common in women.
Other factors can also lead to Osteoarthritis of the knee
- Osteoarthritis of the knee tends to run in families.
- Being overweight increases the risk of Osteoarthritis of the knee joints because extra weight causes more wear and tear.
- Fractures or other joint injuries can lead to OA later in life. This includes injuries to the cartilage and cruciate ligaments in your knee joints.
- Jobs that involve kneeling or squatting for more than an hour a day put you at the highest risk. Jobs that involve lifting, climbing stairs, or walking also put you at risk.
- Playing sports that involve direct impact on the joint (such as football), twisting (such as basketball or soccer), or throwing also increase the risk of arthritis.
Medical conditions that can lead to Osteoarthritis of the knee include:
- Bleeding disorders that cause bleeding in the joint, such as hemophilia
- Disorders that block the blood supply near a joint and lead to avascular necrosis
- Other types of arthritis, such as chronic gout, pseudogout, or rheumatoid arthritis
Pain and stiffness in the knee joints are the most common symptoms. The pain is often worse after exercise and when you put weight or pressure on the joint.
If you have Osteoarthritis of the knee, your knee joints probably become stiffer and harder to move over time. You may notice a rubbing, grating, or crackling sound when you move the knee joint.
The phrase “morning stiffness” refers to the pain and stiffness you may feel when you first wake up in the morning. Stiffness usually lasts for 30 minutes or less. It is improved by mild activity that “warms up” the joint.
During the day, the pain may get worse when you’re active and feel better when you are resting. After a while, the pain may be present when you are resting. It may even wake you up at night.
Some people might not have symptoms, even though x-rays show the changes of Osteoarthritis of the knee.
Signs and tests
A physical exam can show:
- Joint movement may cause a cracking (grating) sound, called crepitation
- Joint swelling (bones around the joints may feel larger than normal)
- Limited range of motion
- Tenderness when the joint is pressed
- Normal movement is often painful
No blood tests are helpful in diagnosing Osteoarthritis of the knee.
An x-ray of affected joints will show a loss of the joint space. In advanced cases, there will be a wearing down of the ends of the bone and bone spurs.
Osteoarthritis of the knee will most likely get worse over time. However, your Osteoarthritis of the knee symptoms can be controlled.
You can have surgery, but other treatments can improve your pain and make your life much better. Although these treatments cannot make the arthritis go away, they can often delay surgery.
Over-the-counter pain relievers, which you can buy without a prescription, can help with Osteoarthritis of the knee symptoms. Most doctors recommend acetaminophen (Tylenol) first, because it has fewer side effects than other drugs. If your pain continues, your doctor may recommend nonsteroidal anti-inflammatory drugs (NSAIDs). Types of NSAIDs include aspirin, ibuprofen, and naproxen.
Other medications or supplements that you may use include:
- Corticosteroids injected right into the joint to reduce swelling and pain
- Over-the-counter remedies such as glucosamine and chondroitin sulfate
- Capsaicin (Zostrix) skin cream to relieve pain
- Artificial joint fluid (Synvisc, Hyalgan) can be injected into the knee to relieve pain for 3 – 6 months
Staying active and getting exercise helps maintain joint and overall movement. Ask your health care provider to recommend an appropriate home exercise routine. Water exercises, such as swimming, are especially helpful.
Other lifestyle recommendations include:
- Applying heat and cold
- Eating a healthy, balanced diet
- Getting rest
- Losing weight if you are overweight
- Protecting the joints
As the pain from your Osteoarthritis of the knee becomes worse, keeping up with everyday activities may become more difficult or painful.
- Sometimes making changes around the home will take some stress off your joints, and relieve some of the pain.
- If your work is causing stress in certain joints, you may need to adjust your work area or change work tasks.
Severe cases of Osteoarthritis of the knee might need surgery to replace or repair damaged joints. Surgical options include:
- Arthroscopic surgery to trim torn and damaged cartilage
- Changing the alignment of a bone to relieve stress on the bone or joint (osteotomy)
- Surgical fusion of bones, usually in the spine (arthrodesis)
- Total or partial replacement of the damaged joint with an artificial joint (knee replacement, hip replacement, shoulder replacement, ankle replacement, elbow replacement)
Every person with Osteoarthritis of the knee is different. Pain and stiffness may prevent one person from performing simple daily activities, while others are able to maintain an active lifestyle that includes sports and other activities.
Your movement may become very limited over time. Doing everyday activities, such as personal hygiene, household chores, or cooking may become a challenge. Treatment usually improves function.