Regional versus general anesthesia in knee arthroplasty in patients with different classes of BMI: A matched analysis of the NSQIP database

Background: Knee arthroplasty for knee arthritis is a commonly performed surgery yielding excellent functional results and good pain relief. It is associated with post-surgical complications according to the type of anesthesia and BMI class.

Methods: The National Surgical Quality Improvement Project database for the years 2005-2012 for patients >18 years of age who underwent knee arthroplasty, condyle and plateau, medial and/or lateral compartment. The surgical site complications, bleeding occurrences necessitating transfusion, unplanned readmissions, and mortality stratified according to anesthesia type and BMI class over a period of 30-days were examined.

Results: A total of 78,275 patients were included for analysis; regional anesthesia showed a consistent protective effect from surgical site complications more prominent with increasing obesity class with respective ORs and their corresponding 95% CI for pre-obesity, class I, II, and III obesity being 0.95 [0.89-1.09], 0.75 [0.68-0.83], 0.64 [0.57-0.72], and 0.61 [0.54-0.7].

Conclusions: Higher BMI values are a protective factor for the risk of bleeding requiring transfusion in patients undergoing total knee arthroplasty. Moreover, regional anesthesia is the preferred choice of anesthesia as well if postoperative complications are considered. A significant decrease in the rate of post-operative blood transfusions was seen in patients with high BMI and regional anesthesia.