The knee is made up of three bones. The ends of the three bones are covered with a thick cartilage, which provides cushion and absorbs force placed on the bones. Knee arthritis affects the cartilage in the knee.
Causes
Knee arthritis is a condition caused by the breakdown of cartilage in the knee. As the cartilage wears away, the cushioning space between the bones decreases, which leaves the bones rubbing together.
The reason the condition develops appears to be a gradual wear and tear on the knee. Risk factors for developing knee arthritis include increased age and being overweight. People who have had a repetitive sports injury to the knee are also at an increased risk of developing knee arthritis.
Symptoms and Natural History
The main symptoms of knee arthritis include pain and stiffness of the joint. The knee may also become swollen. Some people also find the knee may lock when they try to bend it.
In most cases, knee arthritis starts gradually. Pain and stiffness may come and go over a long period of time. For example, some people may only notice stiffness when they first get up in the morning. As the condition progresses, pain may become more severe.
Depending on how severe the pain is, knee arthritis may limit participation in activities once enjoyed, such as sports. But recreational activities are not the only thing that may be impacted if you have knee arthritis. If symptoms are severe, daily living activities, such as walking and going up and down stairs can be difficult.
Diagnosis
A physical exam will help your doctor determine if you have knee arthritis. During the exam, your doctors will evaluate your knee for areas of tenderness, range of motion limitations, swelling and instability.
Imaging studies are also usually done to make a diagnosis of knee arthritis. For example, an x-ray may be ordered to check for a narrowing of joint space in the knee. In some instances, your doctor may order more detailed imaging tests, such as a CT scan or an MRI.
Self-help Treatments for Knee Arthritis
Once a diagnosis is made, treatment may depend on how severe symptoms are and how much they interfere with your quality of life. Self-help treatments are almost always advised. For example, resting the knee and decreasing activities that increase symptoms is usually a good idea.
If you are overweight, getting to a healthy weight helps place less stress on the joint and may decrease pain. Applying heat may help with stiffness and improve range of motion.
Standard Clinical Treatments for Knee Arthritis
Clinical treatment for knee arthritis may include steroid injections to decrease pain and inflammation. Viscosupplementation is another treatment option, which may be helpful. The procedure involves injecting hyaluronic acid into the joint to improve the quality of the synovial fluid and decrease pain and friction.
If all other options fail and symptoms are significant, surgery may be recommended. A partial or total knee replacement may restore function to the knee and eliminate symptoms of knee arthritis. During the procedure, the damaged cartilage and bone is removed and replaced with a new joint made of metal, plastic or a combination of materials.
Sources
American Academy of Orthopaedic Surgeons. Arthritis of the Knee. http://orthoinfo.aaos.org/topic.cfm?topic=a00212
University of Washington Orthopedic and Sports Medicine. Knee Arthritis. http://www.orthop.washington.edu/?q=patient-care/articles/knee/knee-arthritis.html
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