Types of Arthritis: Knee Arthritis

By Lewis, Sarah, PharmD

Millions of Americans visit the doctor each year for knee pain. Your knee is the largest joint in your body. It connects your kneecap to the bottom of your thigh bone and the top of your shinbone. It’s also a very complex joint with many structures, such as cartilage and ligaments that help keep it stable. This makes your knee vulnerable to a variety of injuries and disabilities, including arthritis.

How Will I Know If I Have Knee Arthritis?

You may suspect you have knee arthritis if your knee is stiff, painful and swollen. These symptoms usually start slowly. You may notice that symptoms are worse in the morning or if you’ve been inactive. However, your symptoms may also occur after activities that stress your knee, such as hiking and running. Eventually, you may have trouble bending and straightening your knee and it may feel as if your knee is locking, giving out, or buckling.

If you have symptoms of knee arthritis, contact your doctor. To diagnose knee arthritis, your doctor will complete a medical history and physical exam and may order certain tests, such as blood tests and X-rays. Blood tests are used to diagnose rheumatoid arthritis (RA) and X-rays are used to check for damage to your knee joint.

Are There Different Types of Knee Arthritis?

Osteoarthritis (OA) is the most common type of knee arthritis. It’s also called degenerative joint disease, or degenerative arthritis. In OA, the protective cartilage of your joint wears away slowly with time. This allows the bones to rub directly together without cushioning, causing pain, swelling and stiffness. OA may affect one or both of your knees.

Post-traumatic arthritis is similar to OA. It develops after a knee injury and may not be apparent for many years after the injury.

Rheumatoid arthritis (RA) is inflammatory arthritis and an autoimmune disease in which your immune system starts attacking your own joint tissues. This causes inflammation that can break down your cartilage, bones, muscles, tendons and ligaments. RA will almost always affect both of your knees as well as other joints in your body.

Septic arthritis is caused by a joint infection. Your knee joint can become infected from the spread of a preexisting infection in your blood to your joint or from an open knee wound, for example. Artificial knee joints are also at risk of septic arthritis.

Your doctor can tell the difference between OA, RA, septic arthritis, and post-traumatic arthritis with blood tests, biopsies, and X-rays. Your doctor will also evaluate which joints are affected, when you have symptoms, and if you have other symptoms, such as fatigue, low-grade fever, and muscle aches, all of which are symptoms of RA.

Who Gets Knee Arthritis?

Health experts don’t know exactly what causes osteoarthritis of the knee, but they do know that the following factors increase your risk of developing this type of arthritis:

  • Family history of arthritis

  • Overweight or obesity

  • Older age, especially 50 years and older

  • Female gender

  • Repetitive stress injuries to your knees. This is common with activities that require you to kneel or squat a lot. Performing artists and floor or carpet layers often suffer these types of injuries.

  • High-impact sports, especially running, tennis and soccer

  • History of diseases that affect your knees such as septic arthritis

What Can Be Done to Remedy Knee Arthritis?

You can’t reverse joint damage caused by RA or OA. But you can treat both RA and OA to decrease your pain and swelling and possibly prevent further damage to your joint. Treatment includes anti-inflammatory medicines, physical therapy and knee strengthening exercises, and heat or cold therapy. If you do participate in high-impact activities, you should probably avoid them or stop them altogether to prevent further deterioration of your joint.

Glucosamine and chondroitin sulfate supplements can help relieve swelling and pain and improve joint function in some people in early stages of OA, although their effectiveness varies widely. If none of these treatments relieve your symptoms, your doctor may consider surgery. Doctors can resurface the bones in your knee joint to help them glide easier. They can also replace your joint with artificial components.

If you have RA, you will also need medicine to stop or at least inhibit your immune system from attacking your joints. Your doctor will probably prescribe disease-modifying anti-rheumatic drugs (DMARDs) to help slow down permanent joint damage and biologic response modifiers to reduce inflammation and prevent joint damage.

Medical Reviewer: McDonough, Brian, MD Copyright: © Copyright 2012 Health Grades, Inc. All rights reserved. May not be reproduced or reprinted without permission from Health Grades, Inc. Use of this information is governed by the HealthGrades User Agreement.

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Treatments for any type of arthritis are largely the same.