Anesthesia's Impact After Joint Surgery

Neuraxial anesthesia for joint arthroplasty may lead to better outcomes after surgery

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) If you're about to get a hip or knee replacement, you're going to need anesthesia to numb the pain during surgery. There are different types of anesthesia to choose from. So which one leads to the best outcomes?

In a recent study, researchers explored the impact of different anesthesia methods on the post-surgery outcomes of patients undergoing hip or knee replacement surgery.

The study's results showed that patients who received neuraxial anesthesia, which numbs the body from the abdomen to the toes, had better outcomes after surgery than patients who received general anesthesia, which puts patients in a deep sleep so they don't feel pain during surgery.

In addition, patients who received neuraxial anesthesia were less likely to have long hospital stays or high health care costs.

"Ask your surgeon about anesthesia options."

The study was conducted by Stavros Memtsoudis, MD, PhD, director of Critical Care Services at the Hospital for Special Surgery in New York City, and his fellow researchers.

According to Dr. Memtsoudis and colleagues, there is some controversy about the impact of different anesthetic techniques on post-surgery outcomes. 

To address this controversy, the researchers studied 382,236 patients undergoing their first hip or knee replacement surgery who had information on the type of anesthesia they received.

"Other studies have suggested some benefit of neuraxial over general anesthesia, but they looked at very limited outcomes, primarily at risk of bleeding and blood transfusions," said Dr. Memtsoudis in a press release. "What this study does for the first time is really explore the impact of anesthesia on a wider range of important outcomes."

The vast majority (74.8 percent) of patients in this study received general anesthesia, while 11 percent received neuraxial anesthesia and 14.2 percent received a combination of the two.

Although rates of death within 30 days of surgery were low among all study participants, patients who received general anesthesia had higher death rates than those who received neuraxial or a combination of neuraxial and general anesthesia (0.18 percent versus 0.10 percent versus 0.10 percent).

Patients who received general anesthesia also had higher rates of pulmonary compromise (lung complications), infections and acute kidney failure compared to those who received neuraxial or combination anesthesia.

Specifically, rates of pulmonary compromise were 0.81 percent among general anesthesia patients, 0.37 percent among neuraxial patients and 0.61 percent among combination anesthesia patients.

Rates of infection were 4.5 percent among those who received general anesthesia, 3.11 percent among those who received neuraxial and 3.87 percent among those who received combination anesthesia.

Acute renal failure was observed in 1.75 percent of general anesthesia patients, 1.1 percent of neuraxial patients and 1.43 percent of combination patients.

The results of this study also showed that patients who received neuraxial or combination anesthesia had lower rates of prolonged hospital stays. Patients were categorized as having a prolonged hospital stay if their length of time spent in the hospital was among the highest 75th percentile of the whole study group.

Among patients who received general anesthesia, rates of prolonged hospital stays were 35.4 percent. In comparison, rates of prolonged hospital stays were 28.7 percent among neuraxial patients and 27.4 percent among combination anesthesia patients.

The researchers also found an associated between neuraxial anesthesia and lower health care costs. Patients were considered to have high health care costs if their costs fell in the upper 75th percentile of the whole study group.

Rates of high health care costs were 23.4 percent among general anesthesia patients. In comparison, rates of high health care costs were 21.4 percent among neuraxial patients and 18.3 percent among combination anesthesia patients.

As Dr. Memtsoudis framed it in a press release, "Patients were 30 percent more likely to be in the group that had the highest costs if they received general anesthesia alone."

The researchers did not observe any differences in rates of heart attack or other heart-related complications between the groups.

According to Dr. Memtsoudis, "We found lower rates of complications including pulmonary compromise, pneumonia, infections, and acute renal failure when neuraxial anesthesia is used. The choice of anesthesia seemed to basically affect every organ system."

In their paper, Dr. Memtsoudis and colleagues concluded that using neuraxial anesthesia for joint replacement surgeries is associated with better post-surgery outcomes than using general anesthesia. However, "More research is needed to study potential mechanisms for these findings," they wrote.

Dr. Memtsoudis also noted the importance of educating patients on anesthetic techniques.

"Some patients don't like the idea of having an injection in their back and their legs being numb, but a thorough discussion of risks, benefits and alternatives can go a long way to help an educated patient make rational decisions," he said.

This study was observational, meaning the researchers were not able to control for which patients received each type of anesthesia. Randomized clinical trials are considered the "gold standard" of research. However, according to the study's authors, large, randomized controlled trials have not been practical for research on anesthesia methods. That's because there are low rates of outcomes that would require a huge number of patients to fully understand and compare the effects of each method.

This study was published in May in Anesthesiology.

The research was funded by the Hospital for Special Surgery and the Anna-Maria and Stephen Kellen Physician-Scientist Career Development Award.

Reviewed by: 
Review Date: 
April 29, 2013
Last Updated:
November 6, 2013