Total Knee Replacement: A Patient's Guide.

Edited By: Seth S. Leopold, M.D.
Last updated Tuesday, April 15, 2008

Considering surgery

Who should consider total knee replacement surgery for severe arthritis of the knee and in what cases?

It is usually reasonable to try a number of non-operative interventions before considering knee replacement surgery of any type. Prior to surgery, an orthopaedic surgeon may offer medications (either non-steroidal anti-inflammatory medications or analgesics like acetaminophen, which is sold under the name Tylenol), knee injections, or exercises. A surgeon may talk to patients about activity modification, weight loss, or use of a cane.

The decision to undergo the total knee replacement is a "quality of life" choice. Patients typically have the procedure when they find themselves avoiding activities that they used to enjoy because of knee pain. When basic activities of daily life--like walking, shopping, or reasonable recreational pastimes--are inhibited or prevented by the knee pain, it may be reasonable to consider the surgery.

What happens if nothing is done for severe arthritis of the knee (best case/worst case scenarios)?

What options exist for surgery for severe arthritis of the knee?

If a knee surgeon and a patient decide that non-operative treatments have failed to provide significant or lasting relief, there are sometimes different operations to choose from.

Knee arthroscopy

If X-rays don’t show very much arthritis, and the surgeon suspects (or has identified by MRI) a torn meniscus, knee arthroscopy may be a good choice. This is a relatively minor procedure that is usually done as an outpatient, and the recovery is fairly quick in most patients.

However, if X-rays demonstrate a significant amount of arthritis, this may not be a good choice. Knee arthroscopy for arthritis fails to relieve pain in about half of the patients who try it.

Osteotomy

For younger patients (typically under age 40, but this age cutoff is flexible) who desire to return to a high level of athletic activity or physical work, a procedure called osteotomy (which means “cutting the bone”) might be worth considering. This option is suitable only if the arthritis is limited to one compartment of the knee (for more information about arthritis in one compartment of the knee, see the "Location" section on page 2 of this article).

Osteotomy involves cutting and repositioning one of the bones around the knee joint. This is done to re-orient the loads that occur with normal walking and running so that these loads pass through a non-arthritic portion of the knee. That’s why it doesn’t work well if more than one compartment of the knee is involved--in those patients, there is no “good” place through which the load can be redistributed.

Knee fusion

Knee fusion, also called “arthrodesis,” permanently links the femur (thigh bone) with the tibia (shin bone), creating one long bone from the hip to the ankle. It removes all motion from the knee, resulting in a stiff-legged gait.

Because there are so many operations that preserve motion, this older procedure is seldom performed as a first-line option for patients with knee arthritis. It is sometimes used for severe infections of the knee, certain tumors, and patients who are too young for joint replacement but are otherwise poor candidates for osteotomy.

Minimally-invasive partial knee replacement (mini knee)

Patients who are of appropriate age--certainly older than age 40, and older is better--and who have osteoarthritis limited to one compartment of the knee may be candidates for an exciting new surgical technique, minimally-invasive partial knee replacement (mini knee) (see figures 12, 13, and 14). Partial knee replacements have been done for over 20 years, and the “track record” on the devices used for this operation is excellent. The new surgical approach, which uses a much smaller incision than traditional total knee replacement, significantly decreases the amount of post-operative pain, and shortens the rehabilitation period. The decision of whether this procedure is appropriate for a specific patient can only be made in consultation with a skillful orthopaedic surgeon who is experienced in all techniques of knee replacement.

Minimally-invasive partial knee replacement (mini knee) is not for everyone. Only certain patterns of knee arthritis are appropriately treated with this device through the smaller approach.

Generally speaking, patients with inflammatory arthritis (like rheumatoid arthritis or lupus), and patients with diffuse arthritis all throughout the knee should not receive partial knee replacements.

Patients who are considering knee replacements should ask their surgeon whether minimally-invasive partial knee replacement (mini knee) is right for them.

Total knee replacement

Long considered the “gold standard” operation for knee arthritis, total knee replacement is still by far the most commonly-performed joint replacement procedure (see figure 15). It is most suitable for middle-aged and older people who have arthritis in more than one compartment of the knee (see figures 16 and 17), and who do not intend to return to high-impact athletics or heavy labor. Results of this procedure generally are excellent, with 90-95% of total knee replacements continuing to function well more than 10 years after surgery.

Links

• Video: Minimally-Invasive Joint Replacement Video

When performed by an experienced surgeon, how effective is total knee replacement surgery for severe arthritis of the knee likely to be and how long will the benefit last?

Current evidence suggests that when total knee replacements are done well, in properly selected patients, success is achieved in the large majority of patients, and the implant serves the patient well for many years.

Many studies show that 90-95 percent of total knee replacements are still functioning well 10 years after the surgery. Most patients walk without a cane, most can do stairs and arise from chairs normally, and most resume their desired level of recreational activity.

In the event that a total knee replacement requires re-operation sometime in the future, it almost always can be revised (re-done) successfully. However, results of revision knee replacement are typically not as good as first-time knee replacements.

There is good evidence that the experience of the surgeon correlates with outcome in total knee replacement surgery; for this reason, it is best to have the initial surgery done by an individual who is experienced (fellowship-trained, and with a practice that focuses on knee replacement) in this kind of work. Surgeons with this level of experience have been shown to have fewer complications and better results than surgeons who haven’t done as many knee replacements. It is therefore important that the surgeon performing the technique be not just a good orthopaedic surgeon, but a specialist in knee replacement surgery.

How urgent is total knee replacement surgery for severe arthritis of the knee?

Total knee replacement is elective surgery. With few exceptions, it does not need to be done urgently, and can be scheduled around important life-events.

What are the most frequent and most serious risks of total knee replacement surgery for severe arthritis of the knee? How common are they?

Like any major surgical procedure, total knee replacement is associated with certain medical. Although major complications are uncommon, they may occur; the possibilities include blood clots, bleeding, and anesthesia-related or medical risks such as cardiac risks, stroke, and in rare instances (large studies have calculated the risk to be less than 1 in 400), death.

Risks specific to knee replacement include infection (which may result in the need for more surgery), nerve injury, the possibility that the knee may become either too stiff or too unstable to enjoy it, a chance that pain might persist (or new pains might arise), and the chance that the joint replacement might not last the patient's lifetime or might require further surgery.

However, while the list of complications is long and intimidating, the overall frequency of major complications following total knee replacement is low, usually less than 5 percent (one in 20). Obviously, the overall risk of surgery is dependent both on the complexity of the knee problem but also on the patient's overall medical health.

If risks occur during or after total knee replacement surgery for severe arthritis of the knee how are they managed?

Many of the major problems that can occur following a total knee replacement can be treated. The best treatment, though, is prevention. An orthopaedic surgeon will use antibiotics before, during and after surgery to minimize the likelihood of infection. (S)he will take steps to decrease the likelihood of blood clots, such as early patient mobilization and use of blood-thinning medications in some patients. Patients are evaluated by a good internist and/or anesthesiologist in advance of the surgery, in order to decrease the likelihood of a medical or anesthesia-related complication. Good surgical technique can help minimize the knee-specific risks--so choosing a fellowship-trained and experienced knee replacement surgeon is important.

Again, the overall likelihood of a severe complication is typically less than 5 percent when such steps are taken.

Surgery for Severe arthritis of the knee at the University of Washington

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