Compared to general anesthesia for total knee arthroplasty, neuraxial anesthesia was associated with a lower risk of pneumonia and any systemic infectious complication within 30 days of surgery. (Image source: Thinkstock)

Compared to general anesthesia for total knee arthroplasty, neuraxial anesthesia was associated with a lower risk of pneumonia and any systemic infectious complication within 30 days of surgery. (Image source: Thinkstock)

Approximately ½ million knee arthroplasty operations are performed in the United States each year. The fact that the operation is performed on an extremity lends itself to the use of neuraxial anesthesia. Certainly pain is better controlled when neuraxial anesthesia is used. Is the risk of infection any different if neuraxial rather than general anesthesia is utilized? Dr. Jiabin Liu, Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA and colleagues used the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2005 to 2010 to specifically examine the rates of different infectious complications related to the two types of anesthesia this surgical procedure is performed under. Their work is published in this month’s edition of Anesthesia & Analgesia in the article titled “Neuraxial Anesthesia Decreases Postoperative Systemic Infection Risk Compared with General Anesthesia in Knee Arthroplasty.”

To be enrolled in this study, patients had to undergo either partial or total knee arthroplasty. The infectious complications analyzed included superficial wound infection, deep incisional wound infection, organ space surgical site infection, surgical wound disruption, pneumonia, urinary tract infection, sepsis, and septic shock. There were over 7,000 patients included in the neuraxial anesthesia group and over 9,000 patients who underwent general anesthesia for the procedure. The group of patients who received neuraxial anesthesia had lower rates of pneumonia and composite systemic infection. The logistic regression analysis model for risk of pneumonia included anesthesia type, age, gender, race, CNS disease, diabetes, dyspnea, and functional health status before surgery. With the use of regional anesthesia, pneumonia risk decreased by about 50% and the risk of systemic infection decreased by about 25%.

As with most of these larger multi-hospital studies, the analyses are retrospective and use a multi-hospital database. Coding can be incorrect. Certain subtleties can be missed: for example, some patients may have received both general and neuraxial anesthesia, and in case both were used, the patients are listed as having received general anesthesia. What is needed is a prospective randomized study to confirm this study’s findings.