Simultaneous and Concurrent and Bilateral TKA: Why?

Total knee arthroplasty is one of the more routinely successful surgical interventions in medicine, and, occasionally, surgeons will perform simultaneous TKA. Once in a blue moon they’ll even attempt a simultaneous AND concurrent TKA. But, simultaneous, concurrent AND bilateral TKA? What does that even look like?

Researchers from Dartmouth College, Hanover, New Hampshire, have an answer and it is in a new study “Long-term Implant Survivorship and Modes of Failure in Simultaneous Concurrent Bilateral Total Knee Arthroplasty.” The work appears in the August 14, 2019 edition of The Journal of Arthroplasty.

Co-author Wayne Moschetti, M.D., orthopedic surgeon with the Geisel School of Medicine at Dartmouth, explained why he and his colleagues decided to study simultaneous concurrent bilateral total knee arthroplasty telling OTW, “Bilateral total knee replacement (TKA) is not a common occurrence like unilateral TKA. What is even less common is simultaneous concurrent bilateral TKA (two surgical teams performing surgery at the same time).”

“Interestingly enough, our institution has been performing bilateral TKA in this manner for many years and have published previously on short term outcomes. Due to the rarity of this surgical technique and our long-term follow up we felt like this presented a good opportunity for a long term-follow up study. We had the opportunity to address not only the outcomes related to the bilateral procedure but the long-term survivorship of TKA.”

Moschetti and his colleagues reviewed the medical records from 266 consecutive patients (532 knees) who’d received their new knee in simultaneous concurrent bilateral procedures. They specifically documented each patient’s preoperative characteristics, perioperative complications, and revision surgeries.

Dr. Moschetti described one of the more interesting aspects of this study for OTW, “I think this study can be looked at as not only an assessment of long-term follow after bilateral TKA but a survivorship study for TKA in general. In our cohort the survivorship for revision of either knee was similar to published results in the literature. Once you include the second TKA though the revision rate for ‘the patient’ increases as now they’ve had double the exposure.”

“Simply put, patients who have had two knee replacements are more likely to undergo revision surgery then if you were to consider each knee in isolation. Younger patients were also more likely to undergo revision surgery which is not unexpected and consistent with the literature. The most common causes of revision surgery: aseptic loosening (40%) and poly wear (34%), hopefully are things that have been addressed with modern implant design and improved materials which could lead to lower revision rates in the future.”

“This study looked specifically at patients undergoing simultaneous concurrent bilateral TKA and we have shown that in the long term the survivorship of either knee is comparable to the literature.”

“Thus, this appears to be a safe long-term procedure that does not jeopardize implant survivorship with the implants followed in this study.”

“It is important though to discuss with patients that their cumulative risk of reoperation is greater when considering both knees. This information could be extrapolated to any patient who has had both knees replaced as they have now had double the exposure, but this was out of the scope of this study.”

“Simultaneous concurrent bilateral TKA is a reasonable option for patients with severe bilateral knee osteoarthritis. This study did not investigate specifics with regard to cost, revenue, scheduling logistics, staffing and medical complications which are factors that would need to be assessed on the institutional level. At our facility we’ve had the infrastructure in place to allow for simultaneous concurrent bilateral TKA and that might not be the case everywhere.”