Bilateral Knee Replacement Risks and Benefits

Weighing the Benefits and Risks

Total knee replacement, X-rays
Knee replacement. ZEPHYR / Getty Images

A knee replacement is a surgical procedure that replaces your knee joint with an artificial prosthesis (i.e, joint replacement surgery). The procedure is usually performed after conservative treatments fail to relieve arthritis pain and when severe joint damage interferes with joint function and the ability to perform daily activities. Knee replacement is considered a highly successful surgery and it's not uncommon.

According to the Agency for Healthcare Research and Quality, more than 600,000 knee replacements are performed each year in the United States.

Many people only require a knee replacement for one of their knees. But some people need both of their knees replaced. When both knees need to be replaced, it can be done one of three ways:

1 - as a staged procedure (one knee and then the other with a time interval between, usually months)
2 - during the same operation, with one surgical team replacing both knees, one right after the other
3 - during the same operation, with two surgical teams replacing both knees simultaneously

Benefits of Bilateral Knee Replacement

Simultaneously replacing both knees has benefits, as well as risks. Some of the benefits are obvious -- for example, the opportunity to get the procedures over with in a single event and only having to undergo anesthesia once, rather than twice.

Having one anesthesia may result in a shorter hospital stay. Also, symmetrical rehabilitation of the knee replacements may have advantages.

I underwent bilateral knee replacement surgery in 1988. I was considered a good candidate for the bilateral procedure. I was relatively young (32 years old at the time) and in generally good health, aside from having rheumatoid arthritis.

Truth be told, although I was agreeable to doing both at once and anxious to get it over with, I was surprised how painful it was and how difficult rehabilitation sessions were without a good leg to stand on. Even with that admission, I think it was worth it to have the simultaneous bilateral procedure. Just know that it's not easy.

Cost effectiveness is a consideration too. It has been reported, largely due to the single hospital stay and rehabilitation schedule, that simultaneous bilateral knee replacement results in a 36% cost reduction per patient. When bilateral knee replacement is performed as a staged operation, cost actually goes up 20%.

Risks of Bilateral Knee Replacement

Researchers have considered the risks involved with simultaneous bilateral knee replacement. They concluded that there is an appropriate patient population for the procedure but that people who are 80 years old and older should not have the bilateral procedure due to a high rate of complications.

In simultaneous bilateral knee replacement procedures, safety has been questioned because of a higher rate of cardiac, pulmonary, and neurological complications, as well as a greater need for blood transfusions. Thirty day mortality rates were found to be higher for simultaneous bilateral knee replacement compared to unilateral or staged knee replacements.

The cardiac and pulmonary health or older age of some patients may account for the higher mortality risk.

There has been conflicting information presented for deep vein thrombosis. Earlier studies report higher rates of deep venous thrombosis related to simultaneous bilateral knee replacement. Interestingly, more recent studies claim deep vein thrombosis is lower after bilateral knee replacement.

There are fewer joint infections with a simultaneous bilateral knee replacement than with a staged procedure -- and fewer revisions (repeat procedures after prosthesis failure or infection). After assessing benefits and risks, it makes sense that high-risk patients with comorbid conditions should be steered towards doing one knee at a time.

One study revealed that, after analyzing more than 42,000 discharge records, 9.5% had major complications, most of which were heart-related during hospitalization. Suffice to say, it is up to your physician and your surgeon to determine if you are a good candidate for simultaneous bilateral knee replacement -- and to determine what defines a good candidate for that particular procedure.


Two Knee Replacements May Be Better Than One. AAOS. 2/18/2011.

Memtsoudis SG, Ma Y, Chiu YL, Poultsides L, Gonzalez Della Valle A, Mazumdar M. Bilateral total knee arthroplasty: risk factors for major morbidity and mortality. Anesthesia-Analgesia. 2011 Oct;113(4):784-90. Epub 2011 Jul 13.

Morbidity and Mortality of Simultaneous Bilateral Total Knee Arthroplasty. Milesh P. et al. Orthopedics. August 2008.

Total Knee Replacement. AAOS Orthoinfo. December 2011.

Knee Replacements Up Dramatically Among Adults 45 to 64 Years Old. AHRQ News and Numbers. November 3, 2011.


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