Ready to Consider Knee Joint Replacement? You're Not Alone

If arthritis (or injury) has damaged your knee, and different treatments for your pain haven't helped you get through your everyday activities comfortably, you may be ready to consider knee replacement surgery. You'll be in good company: More than a quarter-million Americans have knee replacement surgery every year. First performed in 1968, the procedure typically relieves pain and restores joint function.

DECISION STEP 1:
Understanding How The Knee Works

By understanding how a normal, healthy knee works, it will be easier for you to understand the way a knee joint prosthesis, or artificial knee joint, works -- and the difference it may make in your life.

A joint is formed by 2 or more bones that are connected by thick bands of tissue called ligaments. The knee is the largest joint in the body and is made up of three main parts:

• The lower end of the thigh bone, or femur
• The upper end of the shin bone, or tibia 
• The kneecap, or patella

The thigh bone (femur) turns on the upper end of the shin bone (tibia), and the kneecap (patella) slides in a groove on the end of the thigh bone. Ligaments, which are bands of tissue, connect the thigh bone and the shin bone to help keep the knee joint steady. The quadriceps, the long muscles on the front of the thigh, help strengthen the knee.

A smooth substance called articular cartilage covers the surface of the bones where they touch each other within the joint. This articular cartilage acts as a cushion between the bones. The rest of the surfaces of the knee joint are covered by a thin, smooth tissue liner called synovial membrane, which makes a small amount of fluid that acts as a lubricant.


What Causes Knee Joint Pain?

One of the most common causes of joint pain is arthritis. The most common types of arthritis are:

• Osteoarthritis (OA) -- sometimes called degenerative arthritis because it is a "wearing out" condition involving the breakdown of cartilage in the joints. When cartilage wears away, the bones rub against each other, causing pain and stiffness. OA usually occurs in people aged 50 years and older, and frequently in individuals with a family history of osteoarthritis. 
• Rheumatoid Arthritis (RA) -- produces chemical changes in the joint space that cause it to become thickened and inflamed. In turn, the synovial fluid destroys cartilage. The end result is cartilage loss, pain, and stiffness. RA affects women about 3 times more often than men, and may affect other organs of the body.
• Post-traumatic Arthritis -- may develop after an injury to the joint in which the bone and cartilage do not heal properly. The joint is no longer smooth, and these irregularities lead to more wear on the joint surfaces. 
• Other causes of joint pain -- include avascular necrosis, which can result when bone is deprived of its normal blood supply (for example, after organ transplantation or long-term cortisone treatment), and deformity or direct injury to the joint. In some cases, joint pain is made worse by the fact that a person will avoid using a painful joint, weakening the muscles and making the joint even more difficult to move.

What's causing your knee joint pain?
Is getting relief through joint replacement an option for you? These are just some of the answers that an orthopedic surgeon can provide. But first, it's a good idea to be sure you have information about joint replacement that will help you understand what the surgeon tells you.

DECISION STEP 2:
Learning What You Should Know About Knee Joint Replacement

"Joint replacement " (the term orthopaedic surgeons use) is usually reserved for patients who have severe arthritic conditions. Most patients who have artificial knee joints are over 55 years of age, but the operation is being performed in greater numbers on younger patients thanks to new advances in artificial joint technology.

Circumstances vary, but generally patients are considered for total joint replacement if:

• Functional limitations restrict not only work and recreation, but also the ordinary activities of daily living.
• Pain is not relieved by more conservative methods of treatment -- such as medications, physical therapy, or arthroscopy (cleaning the joint) -- by the use of a cane, and/or by restricting activities.
• Stiffness in the joint is significant.
• X-rays show advanced arthritis or other problems.

What Is Total Joint Replacement?
Total joint replacement is a surgical procedure in which certain parts of an arthritic or damaged joint, such as a knee joint, are removed and replaced with a prosthesis, or artificial joint. The artificial joint is designed to move just like a normal, healthy joint.

In total knee replacement, the artificial joint is composed of metal and polyethylene to replace the diseased joint. The artificial joint is most commonly anchored into place with bone cement. In some applications, it is covered with an advanced material that allows bone tissue to grow into it.
Possible Complications of Surgery

As with any major surgical procedure, patients who undergo total joint replacement are at risk for certain complications, the vast majority of which can be successfully avoided and/or treated. In fact, the complication rate following joint replacement surgery is very low: Serious complications, such as joint infection, occur in less than 2% of patients. (Besides infection, possible complications include blood clots and lung congestion, or pneumonia.)

Will an Artificial Knee Joint Last Forever?
As successful as most of these procedures are, over the years, the artificial joints can become loose and unstable or wear out, requiring a revision (repeat) surgery. These issues -- together with the fact that increasing numbers of younger and more active patients are receiving total joint replacement, and patients are living longer -- have challenged the orthopaedic industry to try to extend the life cycle of total joint replacements.

DECISION STEP 3:
Having an Orthopaedic Evaluation

If you're ready to consider having knee joint replacement, the next important step is to talk with an orthopaedic surgeon. The medical management of arthritis and joint degeneration may be handled by a family doctor, an internist, or a rheumatologist. However, when medical management is not effective, an orthopaedic surgeon should be consulted to determine if surgery is an option. In some cases, the orthopaedic surgeon may be the first physician to make the diagnosis of arthritis.

While every orthopaedic evaluation is different, there are many commonly used tests that an orthopaedic surgeon may consider in evaluating a patient's condition. In general, the orthopaedic evaluation usually consists of: 

• A thorough review of your medical history
• A physical examination 
• X-rays
• Additional tests as needed

The information that the orthopaedic surgeon gathers during the medical history usually suggests the possibility of several different diagnoses (causes). After the medical history is taken, the orthopaedic surgeon conducts a physical examination.

After the physical examination, X-ray evaluation is usually the next step in making the diagnosis. The X-rays help show how much joint damage or deformity exists. An abnormal X-ray may reveal:

• Narrowing of the joint space
• Cysts in the bone
• Spurs on the edge of the bone
• Areas of bony thickening called sclerosis
• Deformity or incorrect alignment
• Other abnormalities

Additional tests may include laboratory testing of blood, urine, or joint fluid and/or magnetic resonance imaging or a bone scan of the joint and surrounding soft tissue.

Treatment Options

Following the orthopaedic evaluation, the orthopaedic surgeon will review and discuss the results with you. Based on his or her diagnosis, your treatment options may include: 

• Medication
• Physical therapy
• Arthroscopy -- cleaning the joint
• Knee joint fluid supplements (injections that provide temporary pain relief)
• Knee joint replacement

If you and your orthopaedic surgeon decide that knee joint replacement surgery is an option to relieve your pain, the orthopaedic surgeon will provide the specific-to-you details of which type of artificial joint he or she will use, what you need to know to prepare for the surgery, how the surgery will be performed, and what results you can expect once you're up and moving again.

Next Steps: Adjusting to Life With Less Knee Joint Pain

The vast majority of individuals who have joint replacement surgery experience a dramatic reduction in joint pain and a significant improvement in their ability to participate in the activities of daily living.


Keep in mind, however, [that] joint replacement surgery will not allow you to do more than you could before joint problems developed. After joint replacement, a good rule of thumb is that acceptable physical activities should: 

• Not cause pain, including pain felt later.
• Not jar the joint, as happens with running or jumping.
• Not place the joint in the extremes of its range of motion

It is also important for an individual with a joint replacement to keep his or her body weight as close to normal as possible. Joint wear and loosening may increase with weight increase.

When fully recovered, most patients can return to work, although some types of work -- such as construction work, certain types of carpentry, and occupations that involve repeated or high climbing -- may not be advisable for individuals with a joint replacement. Also, athletic activities that place excessive stress on the joint replacement should be avoided.

A Final Word: The Decision Is Always Yours

Remember, even if your orthopaedic surgeon determines that knee joint replacement is a good medical option for you, it is still up to you to make the final decision. The ultimate goal is for you to be as comfortable as possible... and that always means making the best decision for you based on your own individual needs.

Bottom line: You don't have to live with severe knee joint pain and the functional limitations it causes. If you have not experienced adequate results with medication and other conservative treatments, total knee joint replacement may provide the pain relief you long for -- and the resulting return to your favorite activities.