Last reviewed: September 29, 2026

It can be, for the right person. Doing both knees in one operation carries more risk in the first weeks, mostly involving the heart, lungs and blood vessels.

Pooled studies find more blood clots in the lungs, more nervous-system complications such as stroke, and a higher death rate in the first months when both knees are done together. On the other hand, infection is less common, the hospital stay is shorter, and the knees work about as well in the end.

Severe deformity in both legs is a special case. Straightening a badly bowed or bent knee tends to lengthen that leg. In one small study, some people who had one knee done noticed a difference in leg length, while none of those who had both done did. Whether that should decide the timing is untested.

The American Academy of Orthopaedic Surgeons says both knees can be done together in carefully chosen patients, with caution, but not in people at high risk of heart or lung complications. Most of this evidence comes from hospital records rather than trials.

In general:

  • General health, heart and lungs weigh more in this choice than the knees do.
  • With severe deformity in both legs, ask how the timing affects leg length.
  • If done separately, spacing the knees at least three months apart is linked to fewer complications.

Drafted with AI assistance from published sources, reviewed and edited by Babak Sheikh, MD.

Sources:

  • Makaram NS, et al. Simultaneous Bilateral Total Knee Arthroplasty Is Associated With Shorter Length of Stay but Increased Mortality Compared With Staged Bilateral Total Knee Arthroplasty: A Systematic Review and Meta-Analysis. J Arthroplasty. 2021. https://doi.org/10.1016/j.arth.2021.01.045
  • Bensa A, et al. One-Stage Versus Two-Stage Bilateral Total Knee Arthroplasty: A Systematic Review and Meta-Analysis. J Arthroplasty. 2025. https://doi.org/10.1016/j.arth.2025.03.026
  • Meehan JP, et al. A Population-Based Comparison of the Incidence of Adverse Outcomes After Simultaneous-Bilateral and Staged-Bilateral Total Knee Arthroplasty. J Bone Joint Surg Am. 2011. https://doi.org/10.2106/JBJS.J.01350
  • Wang KY, et al. Bilateral Total Knee Arthroplasty: Current Concepts Review. JBJS Rev. 2023. https://doi.org/10.2106/JBJS.RVW.22.00194
  • Hafez MA, et al. The Difference in Leg Lengths Following Total Knee Replacement for Patients With Severe Osteoarthritic Deformity. Int Orthop. 2023. https://doi.org/10.1007/s00264-023-05948-x
  • Sabir AB, et al. Limb Length Discrepancy After Total Knee Arthroplasty: Unilateral Versus Bilateral, a Comparative Study at Tertiary Centre. J Clin Orthop Trauma. 2020. https://doi.org/10.1016/j.jcot.2020.06.041

This is general information about what published research shows. It is not medical advice and it is not about your situation. Reading it does not create a doctor-patient relationship with me. I am a retired orthopedic surgeon and I do not see patients. Talk with your own doctor before changing anything about your care. If something feels suddenly or seriously wrong, get medical care promptly rather than waiting.

This page is provided as is. I make no guarantee that it is accurate, complete or current, and medical evidence changes. Use of it is at your own risk.

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