Types of Bilateral Knee Replacement

A bilateral knee replacement surgery is when both knees are replaced with artificial joints during one procedure. People with severe arthritis in both knees often consider this procedure because it can restore a normal, balanced gait.

Sometimes when one knee joint is replaced, it can be difficult to attain completely normal leg 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. In these cases, the question of timing for bilateral knee replacement surgery often arises.

The knee replacement surgery can either be done simultaneously or in stages—with one knee replacement first and the other several days, weeks, or months later.

The bilateral procedure can also be done for a partial knee replacement when 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 considering a bilateral knee replacement surgery, your doctor will assess your ability to tolerate and recover from surgery. Bilateral knee replacement is a longer surgery than a single knee replacement, making it more demanding on the body. If you have cardiovascular problems, pulmonary disease, or are over the age of 80, you might be advised against a simultaneous procedure.

In fact, studies have shown that simultaneous knee replacement surgery increases the risk of cardiac events and death compared to staged operations.

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 staged replacements. Moreover, the risk remained elevated even after three months (2.45-fold increase) and 12 months (1.89-fold increase). There was no difference in the risk of death while in the hospital or during the operation itself.

Another disadvantage of a simultaneous procedure is that rehabilitation can be far more difficult for older people who don't have a non-surgical leg to stand on or the upper body strength to support themselves during physical therapy.

Benefits of a Simultaneous Knee Replacement

One benefit of a simultaneous knee replacement is that two problems are solved at once. The overall rehabilitation time is shorter, and there is only one hospitalization and one round of anesthesia. This can be a better situation for people who would rather not be away from work for extended periods of time.

The co-payments and out-of-pocket expenses from insurance might be lower with one surgery and a single round of rehabilitation.

What to Expect After a Simultaneous Knee Replacement

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

Within six weeks of completing the surgery, your physical therapy will start and can last between six and 12 weeks. The program typically includes a walking plan and a variety of knee-strengthening exercises.

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

A Word From Verywell

Having knee replacement surgery on both your knees might be necessary to manage pain due to your arthritis. Deciding on the ideal time to have your knee replacements involves careful consideration. For some people, having both knees replaced at the same time can be a great thing, but it can be riskier and the rehabilitation can be more difficult than it would be if your knees are replaced one at a time. Talk to your surgeon about your options.

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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.