Types of Bilateral Knee Replacement

A bilateral knee replacement surgery is one in which both knees are replaced with artificial joints. People with severe arthritis in both knees are often good candidates for this as it is better able to restore a normal, balanced gait. Even if one knee is fixed, it can be difficult for many people to recover completely normal function without ultimately having the other knee fixed. For this reason, it is not uncommon for people to find out they need both knees replaced. Then, the question becomes what is the timing for performing the bilateral knee replacement surgery.

The knee replacement surgery can either be performed simultaneously or staged so that one knee is done first and the other is replaced several days, weeks, or months later. A person is considered a viable candidate based on the same evaluation criteria used for a single knee replacement.

The bilateral procedure can also be performed on persons requiring a partial knee replacement where either the medial (inside) or lateral (outside) portion of the knee is replaced.

A man in physical therapy after his knee surgery
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Risk of a Simultaneous Knee Replacement

When determining how to approach a bilateral knee replacement, the doctor will need to assess how able the person is able to withstand the rigors of the operation. It is a longer surgery and, as such, more demanding on the body. Because of this, persons who have cardiovascular problems, pulmonary disease, or are over the age of 80 are typically advised against a simultaneous procedure.

In fact, studies have shown that persons undergoing a simultaneous replacement have a significantly higher risk of a cardiac event and death compared to a staged operation.

A 2013 review from McMaster University in Ontario, Canada analyzed 18 different studies and reported that individuals undergoing a simultaneous replacement had a threefold increase in the risk of death 30 days following the surgery compared to those who had a staged one. Moreover, the risk remained elevated even after three months (2.45-fold increase) and 12 months (1.89-fold increase). Interestingly, there was no difference is the risk of death while in the hospital or during the operation itself. The key to these statistics was the average age of the recipients (68.8 years).

Another disadvantage of a simultaneous procedure is that rehabilitation can be far more difficult for older persons who neither a "good leg" to stand on nor the upper body strength to support themselves during physical therapy.

Benefits of a Simultaneous Knee Replacement

Clearly, the benefit of a simultaneous knee replacement is that two problems are solved at once. The overall rehabilitation time is shorter, and there are only one hospitalization and one round of anesthesia. Without question, this is the ideal situation for persons who would rather not be away from work for extended periods of time.

Moreover, the co-payments and out-of-pocket expenses from insurance may be far lower with one surgery and a single round of rehabilitation. While this wouldn't factor into the evaluation, it may help direct treatment for those who are viable candidates.

What to Expect After a Simultaneous Knee Replacement

After the replacement surgery is complete, you should expect to be in the hospital for up to 10 days. The extended time is needed, in part, to ensure you are mobile enough to return home safely.

Within six weeks of completing the surgery, physical therapy will start and last anywhere from six and 12 weeks. The program typically includes a walking plan and various knee-strengthening exercises.

Most people who undergo successful rehabilitation will experience marked improvement in mobility and pain relief, even those over the age of 80. In many cases, the complete restoration of mobility is possible.

A Word From Verywell

Performing knee replacement on both knees is sometimes needed to manage pain in people with arthritis of both of their knees. Determining the ideal time to perform these replacements, or to possibly have them done at the same time, is a challenging decision for people. There is often a temptation to have both done at the same time, but it is important to understand that there may be increased risks with this procedure and the rehabilitation may be more difficult. In the right person a bilateral knee replacement can be a great thing, in the wrong person it can lead to a worse recovery than doing them one at a time. Talk to your surgeon and see what he or she recommends for your situation.

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  • Hussain, N.; Chien, T.; Hussain, F. et al. "Simultaneous Versus Staged Bilateral Total Knee Arthroplasty." HSS J. January 24, 2013; 9(1): 50-9. DOI: 10.1007/s11420-012-9315-7.