The knee joint is made up of three bones – the thigh bone (femur), the shin bone (tibia), and the kneecap (patella). The ends of the bones are covered by a hard, white, Teflon-like tissue known as the articular cartilage that helps the bones glide smoothly with joint motion. When the articular cartilage wears down with age this is called osteoarthritis. In addition to loss of cartilage, bone spurs often develop in the joint in patients with osteoarthritis.
Symptoms of arthritis typically involve pain throughout the knee. The pain is worse with weight-bearing activity, such as walking or prolonged standing. Intermittent swelling of the knee may occur as well as a grinding sensation in the knee. As the arthritis progresses, there may be a loss of range of motion in the knee. Some patients complain of pain associated with weather changes.
The diagnosis of osteoarthritis of the knee is typically easily made from history of the patient’s symptoms combined with physical examination findings and review of x-rays.
Treatment of arthritis in the knee depends on the severity of the patient’s symptoms. Initially non-operative methods are recommended, including rest and avoidance of aggravating activities, weight loss to relieve stress on the joint, exercises to alleviate any tightness in the joint, icing, and anti-inflammatory medicines. A cortisone injection into the knee may be helpful in controlling the inflammation associated with arthritis that commonly causes most of the pain associated with the condition. In addition, viscosupplementation (or artificial joint fluid injections) may be recommended. If these options fail to provide lasting relief of pain, then surgery may be recommended.
In patients who develop painful mechanical symptoms such as catching, locking, or painful popping of the joint, arthroscopic removal of loose or torn cartilage tissue may be helpful, though this will not restore the worn cartilage surface. Knee replacement surgery is a surgical treatment where the arthritic ends of the bones are removed and replaced with metal and plastic components to “resurface” the worn ends of the bones. Knee replacement may be recommended when non-operative treatment methods are no longer effective at relieving pain from arthritis.
For more information, visit http://orthoinfo.aaos.org/topic.cfm?topic=A00389.