New York—October 26, 2012
Using regional anesthesia rather than general anesthesia reduces the need for blood transfusions in patients undergoing bilateral total knee replacement, according to a new study by researchers at Hospital for Special Surgery, in New York City.
Currently, the majority of bilateral knee replacements in the United States (as well as single knee replacements) are performed under general anesthesia, and researchers say that a regional anesthesia known as neuraxial anesthesia should be promoted for these procedures.
“The use of neuraxial anesthesia may not always be feasible in every patient, but it should be considered more frequently,” said Stavros Memtsoudis, M.D., Ph.D., director of Critical Care Services at Hospital for Special Surgery (HSS) in New York City, who led the study. “You shouldn’t be asking doctors who don’t use neuraxial anesthesia in their daily practice to suddenly switch over and start doing it, but there is a lot of education that needs to be done in terms of training residents and orthopedic surgeons to point out the impact of the choice of anesthetic technique on outcomes beyond the operating room.” The study appears online ahead of print in the journal Regional Anesthesia and Pain Medicine.
Despite its advantages, bilateral knee replacement is associated with an increased risk of complications, compared with the alternative of operating on one knee at a time. Neuraxial anesthesia involves injecting medication into the fatty tissue that surrounds the nerve roots in the spine (known as an epidural) or into the cerebrospinal fluid that surrounds the spinal cord.
For the last two decades, HSS has increasingly used regional anesthesia for orthopedic procedures, because of a growing body of evidence showing favorable results compared with general anesthesia.
Because the influence of anesthesia on perioperative outcomes after bilateral total knee replacement is unknown, researchers at Hospital for Special Surgery conducted a retrospective review of all bilateral knee replacements performed between 2006 and 2010 using Premier Perspective. This administrative database contains discharge information from approximately 400 acute care hospitals located throughout the United States. The study population included 22,253 patients, but the type of anesthesia used was unclear in 6,566 of the patients. Of the 15,687 patients where anesthesia type could be identified, 6.8% received neuraxial anesthesia, 80.1% received general anesthesia, and 13.1% received a combination of both. The three groups had similar comorbidity burdens.
The investigators discovered that patients receiving neuraxial anesthesia were less likely to receive blood transfusions (28.5%) than patients receiving general anesthesia (44.7%) or the combination (38.0%) (P<0.0001). The researchers identified a trend toward a reduction in major complications, such as pulmonary embolism and mechanical ventilation, with the use of neuraxial anesthesia compared with the other two groups, but this was not statistically significant. The investigators say it is possible that the sample size was too small to find other differences in complication rates, with only 1,066 patients receiving neuraxial anesthesia.
“This study shows the important role that anesthesia plays in terms of perioperative outcomes and that people need to start looking at interventions to reduce complications of bilateral knee replacements, not just patient selection, which is basically the only thing that doctors have been advocating in the last ten years,” said Dr. Memtsoudis.
In recent years, clinicians have been selecting younger patients for bilateral procedures, a practice that by itself may unfortunately be limited in its impact on complications, as it is counteracted by increasing rates of comorbidities, such as obesity, present in orthopedic patients and in the population in general [http://www.hss.edu/newsroom_patient-selection-for-bilateral-tkr.asp]. “You can try to choose healthier people, but that is only going to get you so far,” said Dr. Memtsoudis. “Implementing active interventions, such as selecting a specific anesthetic in order to improve outcomes may be something that we need to do more of.”
Dr. Memtsoudis pointed out that communication with patients is key. “Many patients don’t like the idea of having an injection in their back and their legs being numb, and they are worried about paralysis. There is a lot of misinformation out there,” he said. “You have to take into account comorbidities, patient preferences and other practice specific factors, such as the choice for anticoagulation, but neuraxial anesthesia should at the very least be considered in every patient.”
The price tags associated with neuraxial and general anesthesia are similar. Anesthesia medications used during surgeries are a small fraction of overall health care costs.
More work is needed to identify ways to prevent complications in patients undergoing bilateral knee replacement and a recent conference at Hospital for Special Surgery, chaired by Dr. Memtsoudis, is aiming to do just that. The Consensus Conference on the Creation of Guidelines for Bilateral Knee Arthroplasty involved 40 experts from 16 institutions. The guidelines coming out of this conference, which are expected to be published within the next six months, address issues such as selecting appropriate candidates, determining the appropriate workup and management for a patient undergoing bilateral knee replacement, and how long doctors should wait between procedures if a patient undergoes two operations.
Other authors of the study appearing in Regional Anesthesia and Pain Medicine include Ottokar Stundner, M.D., and Lazaros Poultsides, M.D., Ph.D., from HSS; Ya-Lin Chiu, M.S., Xuming Sun, M.S., Madhu Mazumdar, Ph.D., and Peter Fleischut, M.D., from New York-Presbyterian Hospital; and Peter Gerner, M.D., and Gerhard Fritsch, M.D., from Paracelsus Medical University, Salzburg, Austria. The study was supported by funds from the Clinical Translational Science Center at Weill Cornell Medical College; the National Institutes of Health’s National Center for Advancing Translational Sciences; and the Agency for Healthcare Research and Quality’s Center for Education, Research, and Therapeutics.
About HSS | Hospital for Special Surgery
HSS is the world’s leading academic medical center focused on musculoskeletal health. At its core is Hospital for Special Surgery, nationally ranked No. 1 in orthopedics (for the eighth consecutive year) and No. 3 in rheumatology by U.S. News & World Report (2017-2018). Founded in 1863, the Hospital has one of the lowest infection rates in the country and was the first in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center four consecutive times. An affiliate of Weill Cornell Medical College, HSS has a main campus in New York City and facilities in New Jersey, Connecticut and in the Long Island and Westchester County regions of New York State. In 2017 HSS provided care to 135,000 patients from 80 countries and performed more than 32,000 surgical procedures. In addition to patient care, HSS leads the field in research, innovation and education. The HSS Research Institute comprises 20 laboratories and 300 staff members focused on leading the advancement of musculoskeletal health through prevention of degeneration, tissue repair and tissue regeneration. The HSS Innovation Institute was formed in 2015 to realize the potential of new drugs, therapeutics and devices; the global standard total knee replacement was developed at HSS in 1969, and in 2017 HSS made 130 invention submissions (more than 2x the submissions in 2015). The HSS Education Institute provides continuing medical curriculum to more than 22,000 subscribing musculoskeletal healthcare professionals in 125 countries. Through HSS Global, the institution is collaborating with medical centers worldwide to advance the quality and value of care and to make world-class HSS care more accessible to more people.