Both Knees at Once? The Case For and Against Bilateral Joint Replacement

If both of your knees or both of your hips need replacing, an obvious question emerges: can we do them both at the same time? The answer is medically possible, sometimes advisable, and requires a careful conversation with your surgeon about whether the benefits outweigh the risks for your specific situation.

What bilateral replacement means

Bilateral joint replacement comes in two forms. Simultaneous bilateral replacement means both joints are replaced during a single anesthetic event, either by one surgical team working on both sides sequentially, or by two surgical teams working in parallel. The entire procedure takes two to four hours. Staged bilateral replacement means the joints are replaced in separate surgeries, typically four to twelve weeks apart, each with its own hospital stay and recovery period.

The distinction matters because simultaneous and staged approaches have very different risk profiles, recovery experiences, and cost implications.

The case for simultaneous bilateral

The advantages are straightforward. One anesthesia event instead of two, which means one set of pre-operative tests, one recovery, and one period off work. Total recovery time is shorter: instead of two separate three-to-six-month recoveries (potentially a full year), you go through one recovery of four to eight months. The cost is lower because you pay one facility fee, one anesthesia fee, and one hospital stay instead of two.

For patients who are otherwise healthy and motivated, simultaneous bilateral replacement can mean returning to full function faster than the staged alternative. Physical therapy addresses both joints simultaneously, and you avoid the common complaint of staged patients: "The new knee feels great, but now the old knee feels even worse by comparison."

The case against

Simultaneous bilateral replacement is a bigger physiological stress than a single joint replacement. Studies consistently show higher rates of cardiac events and blood loss with simultaneous bilateral procedures compared to unilateral replacement. The risk is most significant in patients over 75, patients with cardiac disease, patients with BMI over 35, and patients with poorly controlled diabetes or pulmonary conditions.

The rehabilitation is more demanding. After a unilateral knee replacement, your non-surgical leg does heavy lifting during recovery: you push off with it, bear weight on it, and use it as a reference for normal movement. After bilateral replacement, you do not have a "good leg" to rely on. Early mobilization is harder, and the first week to two weeks can feel overwhelming.

Pain management is more complex. Two surgical sites means more inflammation, more swelling, and more pain to manage simultaneously. Some patients describe the first week after bilateral knee replacement as the most physically difficult experience of their lives.

Who is a good candidate

The ideal candidate for simultaneous bilateral joint replacement is under 75 (though fit patients up to 80 are considered), has no significant cardiac, pulmonary, or bleeding disorders, has a BMI under 35 (ideally under 30), has both joints at similar stages of disease severity, is motivated and physically capable of demanding rehabilitation, has a strong support system at home for the first two to four weeks, and understands that the first two weeks will be significantly harder than a single replacement.

Cost comparison

Scenario	US hospital estimate	Colombia (JCI)
Staged bilateral knee (two separate surgeries)	$70,000 - $110,000	$16,000 - $28,000
Simultaneous bilateral knee (one surgery)	$45,000 - $75,000	$14,000 - $22,000
Potential savings from simultaneous	$25,000 - $35,000	$2,000 - $6,000

These are typical 2026 ranges. The domestic savings from simultaneous over staged are substantial because you eliminate a second facility fee and hospital stay. International savings are proportionally smaller because the base cost is already low.

Frequently asked questions

How long is the hospital stay for bilateral replacement?

Simultaneous bilateral knee or hip replacement typically requires a two-to-three night hospital stay, compared to one night for a unilateral procedure. Some patients require a short stay in a rehabilitation facility before going home.

Will insurance cover bilateral replacement?

Most insurance plans cover bilateral replacement, but some require prior authorization for each joint separately. The cost-sharing structure (deductible, copay) may work in your favor: both procedures may count toward the same annual deductible and out-of-pocket maximum, potentially saving you thousands compared to staging across two calendar years.