Degenerative Knee Disease Information

Knee arthritis is a degenerative condition that affects the knee joint and often leads to a significant impairment in the quality of life. Approximately 43 million Americans suffer from arthritis and many have significant knee involvement. It can adversely affect one’s ability to walk, work, and live pain-free.

Anatomy

The knee joint is formed by the intersection of three bones—the bottom of the thigh bone (femur), the top of the shin bone (tibia), and the kneecap (patella). In a healthy knee, each of these three bones is covered on the surface by a cushion of perfectly smooth cartilage. Cartilage enables the joint to glide smoothly.

What is knee arthritis?

Unfortunately, cartilage is a tissue that cannot easily repair itself when damaged. Damage may involve tearing, splitting, or pitting of the cartilage. Sometimes, it occurs from small repeated injuries, such as repetitive overuse, especially in bones that are slightly malformed or poorly aligned. Other times, a single traumatic injury damages the cartilage. Once damage has occurred, further breakdown may gradually unfold until areas of raw bone are exposed. This process is known as “osteoarthritis,” the most common variety of arthritis. Diseases such as rheumatoid arthritis, avascular necrosis, lupus, and bacterial joint infections can also damage the joint cartilage.

Osteoarthritis is the most common type of arthritis that leads a patient to seek knee replacement surgery. It is sometimes referred to as “degenerative joint disease.” Severe osteoarthritis may cause disabling pain and joint deformity. The deformity may cause visible bow leg or knock knee if arthritis affects mainly one side of the knee. On the other hand, arthritis affecting the backside of the kneecap (patellofemoral arthritis) will not be obvious to the onlooker. The two sides of the knee joint and the kneecap area constitute the three knee “compartments” that can be affected individually or in combination by arthritis.

Rheumatoid arthritis is an inflammatory condition that affects the lining of all joints in the body. It causes an inflammatory response in the joint lining which destroys the cartilage cushion and surrounding tissues. Rheumatoid arthritis generally results in rapid destruction of many joints of the body and may affect other organ systems in addition to the joints.

Osteonecrosis or avascular necrosis is a condition in which the bones within the knee lose their blood supply and die. This eventually may lead to the collapse of large segments of the bone supporting the cartilage of the knee joint resulting in destruction of the knee. The main causes of osteonecrosis include:

  • injury such as fracture or dislocation of the knee.
  • steroid use for the treatment of such ailments as lupus, asthma, and kidney transplantation.
  • alcohol abuse.

Treatment

Patients are advised to try conservative (non-surgical) treatments before considering any type of knee replacement surgery. Conservative treatments typically includes use of non-steroidal anti-inflammatory drugs (NSAIDs), reduction of activities that provoke pain, physical therapy to strengthen supportive muscles around the knee, weight loss to reduce the load on the knee, use of well cushioned shoes to reduce shock to the knee, injections of cortisone to reduce inflammation and pain, injections of “visco-supplements” to lubricate the knee joint, heat, ice, heating rubs, and use of walking aids such as a cane or crutches. However, when pain and disability become severe, surgical reconstruction of the knee joint with knee replacement surgery may become necessary.

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