While age is a major risk factor for osteoarthritis of the knee, young people can get it, too. For some individuals, it may be hereditary. For others, osteoarthritis of the knee can result from injury or infection or even from being overweight. Here are answers to your questions about knee osteoarthritis, including how it's treated and what you can do at home to ease the pain.
What Is Osteoarthritis?
Osteoarthritis, commonly known as wear-and-tear arthritis, is a condition in which the natural cushioning between joints -- cartilage -- wears away. When this happens, the bones of the joints rub more closely against one another with less of the shock-absorbing benefits of cartilage. The rubbing results in pain, swelling, stiffness, decreased ability to move and, sometimes, the formation of bone spurs.
Who Gets Osteoarthritis of the Knee?
Osteoarthritis is the most common type of arthritis. While it can occur even in young people, the chance of developing osteoarthritis rises after age 45. According to the Arthritis Foundation, more than 27 million people in the U.S. have osteoarthritis, with the knee being one of the most commonly affected areas. Women are more likely to have osteoarthritis than men.
What Causes Knee Osteoarthritis?
The most common cause of osteoarthritis of the knee is age. Almost everyone will eventually develop some degree of osteoarthritis. However, several factors increase the risk of developing significant arthritis at an earlier age.
- Age. The ability of cartilage to heal decreases as a person gets older.
- Weight. Weight increases pressure on all the joints, especially the knees. Every pound of weight you gain adds 3 to 4 pounds of extra weight on your knees.
- Heredity. This includes genetic mutations that might make a person more likely to develop osteoarthritis of the knee. It may also be due to inherited abnormalities in the shape of the bones that surround the knee joint.
- Gender. Women ages 55 and older are more likely than men to develop osteoarthritis of the knee.
- Repetitive stress injuries. These are usually a result of the type of job a person has. People with certain occupations that include a lot of activity that can stress the joint, such as kneeling, squatting, or lifting heavy weights (55 pounds or more), are more likely to develop osteoarthritis of the knee because of the constant pressure on the joint.
- Athletics. Athletes involved in soccer, tennis, or long-distance running may be at higher risk for developing osteoarthritis of the knee. That means athletes should take precautions to avoid injury. However, it's important to note that regular moderate exercise strengthens joints and can decrease the risk of osteoarthritis. In fact, weak muscles around the knee can lead to osteoarthritis.
- Other illnesses. People with rheumatoid arthritis, the second most common type of arthritis, are also more likely to develop osteoarthritis. People with certain metabolic disorders, such as iron overload or excess growth hormone, also run a higher risk of osteoarthritis.
What Are the Symptoms of Knee Osteoarthritis?
Symptoms of osteoarthritis of the knee may include:
- pain that increases when you are active, but gets a little better with rest
- feeling of warmth in the joint
- stiffness in the knee, especially in the morning or when you have been sitting for a while
- decrease in mobility of the knee, making it difficult to get in and out of chairs or cars, use the stairs, or walk
- creaking, crackly sound that is heard when the knee moves
How Is Osteoarthritis of the Knee Diagnosed?
The diagnosis of knee osteoarthritis will begin with a physical exam by your doctor. Your doctor will also take your medical history and note any symptoms. Make sure to note what makes the pain worse or better to help your doctor determine if osteoarthritis, or something else, may be causing your pain. Also find out if anyone else in your family has arthritis. Your doctor may order additional testing, including:
- X-rays, which can show bone and cartilage damage as well as the presence of bone spurs
- magnetic resonance imaging (MRI) scans
MRI scans may be ordered when X-rays do not give a clear reason for joint pain or when the X-rays suggest that other types of joint tissue could be damaged. Doctors may use blood tests to rule out other conditions that could be causing the pain, such as rheumatoid arthritis, a different type of arthritis caused by a disorder in the immune system.
How Is Osteoarthritis of the Knee Treated?
The primary goals of treating osteoarthritis of the knee are to relieve the pain and return mobility. The treatment plan will typically include a combination of the following:
- Weight loss. Losing even a small amount of weight, if needed, can significantly decrease knee pain from osteoarthritis.
- Exercise. Strengthening the muscles around the knee makes the joint more stable and decreases pain. Stretching exercises help keep the knee joint mobile and flexible.
- Pain relievers and anti-inflammatory drugs. This includes over-the-counter choices such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen sodium (Aleve). Don't take over-the-counter medications for more than 10 days without checking with your doctor. Taking them for longer increases the chance of side effects. If over-the-counter medications don't provide relief, your doctor may give you a prescription anti-inflammatory drug or other medication to help ease the pain.
- Injections of corticosteroids or hyaluronic acid into the knee. Steroids are powerful anti-inflammatory drugs. Hyaluronic acid is normally present in joints as a type of lubricating fluid.
- Alternative therapies. Some alternative therapies that may be effective include topical creams with capsaicin, acupuncture, or supplements, including glucosamine and chondroitin or SAMe.
- Using devices such as braces. There are two types of braces: "unloader" braces, which take the weight away from the side of the knee affected by arthritis; and "support" braces, which provide support for the entire knee.
- Physical and occupational therapy. If you are having trouble with daily activities, physical or occupational therapy can help. Physical therapists teach you ways to strengthen muscles and increase flexibility in your joint. Occupational therapists teach you ways to perform regular, daily activities, such as housework, with less pain.
- Surgery. When other treatments don't work, surgery is a good option.
Is Surgery Used to Treat Knee Osteoarthritis?
If your doctor wants to treat the osteoarthritis in the knee with surgery, the options are arthroscopy, osteotomy, and arthroplasty.
- Arthroscopy uses a small telescope (arthroscope) and other small instruments. The surgery is performed through small incisions. The surgeon uses the arthroscope to see into the joint space. Once there, the surgeon can remove damaged cartilage or loose particles, clean the bone surface, and repair other types of tissue if those damages are discovered. The procedure is often used on younger patients ( ages 55 and younger) in order to delay more serious surgery.
- An osteotomy is a procedure that aims to make the knee alignment better by changing the shape of the bones. This type of surgery may be recommended if you have damage primarily in one area of the knee. It might also be recommended if you have broken your knee and it has not healed well. An osteotomy is not permanent, and further surgery may be necessary later on.
- Joint replacement surgery, or arthroplasty, is a surgical procedure in which joints are replaced with artificial parts made from metals or plastic. The replacement could involve one side of the knee or the entire knee. Joint replacement surgery is usually reserved for people over age 50 with severe osteoarthritis. The surgery may need to be repeated later if the joint wears out again after several years, but with today's modern advancements most new joints will last over 20 years. The surgery has risks, but the results are generally very good.