There are two general kinds of knee problems which are mechanical knee problems and inflammatory knee problems. Some knee problems result from injury, such as a direct blow or sudden movements that strain the knee beyond its normal range of movement. Other knee problems can be caused by arthritis. Arthritis is a degenerative disease that destroys the cartilage in a joint. It can be caused by a fracture or other joint injury, but also can be hereditary or due to unknown causes. Arthritis most commonly affects the hip, knee and hand. When arthritis affects a joint, the cartilage loses its smooth, glistening surface and becomes rough and irregular. The result is further destruction of the rest of the joint as the imperfect surfaces contact one another. The joint may then attempt to create new bone in the form of bone spurs, which can be quite painful. Eventually, pieces of bone and cartilage can break off and end up floating in the joint fluid, which causes yet further destruction to the once-smooth surfaces. The end result is partial or complete destruction of the joint if left untreated.
Osteoarthritis in the knee, results from wear and tear on its parts. However, inflammation that occurs in some rheumatic diseases, such as rheumatoid arthritis, can also damage the knee. Arthritis in the knee most often refers to osteoarthritis. In this disease, the cartilage in the joint gradually wears away. Osteoarthritis may be caused by excess stress on the joint from deformity, repeated injury, or excess weight. It most often affects middle-aged and older people. A young person who develops osteoarthritis may have an inherited form of the disease or may have experienced continuous irritation from an unrepaired torn meniscus or other injury. Most often osteoarthritis in the knee is treated with pain-reducing medicines, such as aspirin, Tylenol, or nonsteroidal anti-inflammatory drugs. Exercise is essential to restore joint movement and strengthen the knee. Losing excess weight can also help people with osteoarthritis.
With rheumatoid arthritis, which can also affect the knees, the joint becomes inflamed and cartilage may be destroyed. Arthritis not only affects joints, it can also affect supporting structures such as your muscles, tendons, and ligaments. Rheumatoid arthritis often affects people at an earlier age than osteoarthritis. Rheumatoid arthritis in the knee may require physical therapy and more powerful medications. In people with arthritis in the knee, a seriously damaged joint may need to be replaced with an artificial one during a surgical procedure. Blood tests may be helpful for diagnosing rheumatoid arthritis, but other tests may be needed too. Analyzing fluid from the knee joint can be helpful in diagnosing some types of arthritis. The doctor may use arthroscopy to directly see damage to cartilage, tendons, and ligaments and to confirm a diagnosis, but arthroscopy is usually done only if a repair procedure is to be performed and not just for diagnosing.
Someone who has arthritis in the knee may experience pain, swelling, and a decrease in knee motion. A common symptom is morning stiffness that lessens as the person moves around. Sometimes the joint locks or clicks when the knee is bent and straightened, but these signs may occur in other knee disorders as well. The doctor may confirm the diagnosis by performing a physical examination and examining x-rays, which typically show a loss of joint space.