The Impact of Anesthetic Management on Surgical Site Infections in Patients Undergoing Total Knee or Total Hip Arthroplasty.

BACKGROUND: Surgical site infection (SSI) is one of the most challenging and costly complications associated with total joint arthroplasty. Our primary aim in this case-controlled trial was to compare the risk of SSI within a year of surgery for patients undergoing primary total knee arthroplasty (TKA) or total hip arthroplasty (THA) and revision TKA or THA under general anesthesia versus neuraxial anesthesia. Our secondary aim was to determine which patient, anesthetic, and surgical variables influence the risk of SSI. We hypothesized that patients who undergo neuraxial anesthesia may have a lesser risk of SSI compared with those who had a general anesthetic. METHODS: We conducted a retrospective, case-control study of patients undergoing primary or revision TKA and THA between January 1, 1998, and December 31, 2008, who subsequently were diagnosed with an SSI. The cases were matched 1:2 with controls based on type of joint replacement (TKA versus THA), type of procedure (primary, bilateral, revision), sex, date of surgery (within 1 year), ASA physical status (I and II versus III, IV, and V), and operative time (<3 vs >3 hours). RESULTS: During the 11-year period, 202 SSIs were identified. Of the infections identified, 115 (57%) occurred within the first 30 days and 87 (43%) occurred between 31 and 365 days. From both univariate and multivariable analyses, no significant association was found between the use of central neuraxial anesthesia and the postoperative infection (univariate odds ratio [OR] = 0.92; 95% confidence interval [CI], 0.63-1.34; P = 0.651; multivariable OR = 1.10; 95% CI, 0.72-1.69; P = 0.664). The use of peripheral nerve block also was not found to influence the risk of postoperative infection (univariate OR = 1.41; 95% CI, 0.84-2.37; P = 0.193; multivariable OR = 1.35; 95% CI, 0.75-2.44; P = 0.312). The factors that were found to be associated with postoperative infection in multivariable analysis included current smoking (OR = 5.10; 95% CI, 2.30-11.33) and higher body mass index (BMI) (OR = 2.68; 95% CI, 1.42-5.06 for BMI ≥ 35 kg/m compared with those with BMI < 25 kg/m). CONCLUSIONS: Recent studies using large databases have concluded that the use of neuraxial compared with general anesthesia is associated with a decreased incidence of SSI in patients undergoing total joint arthroplasty. In this retrospective, case-controlled study, we found no difference in the incidence of SSI in patients undergoing total joint arthroplasty under general versus neuraxial anesthesia. We also concluded that the use of peripheral nerve blocks does not influence the incidence of SSI. Increasing BMI and current smoking were found to significantly increase the incidence of SSI in patients undergoing lower extremity total joint arthroplasty.

Elution of High Dose Amphotericin B Deoxycholate From Polymethylmethacrylate.

Fungal periprosthetic joint infections are rare, devastating complications of arthroplasty. There is conflicting evidence as to the efficacy of amphotericin B elution from cement spacers. The purpose of this study was to determine whether concentrations of amphotericin B released from bone cement over time would be efficacious in treating a periprosthetic infection. A continuous flow chamber was used to evaluate the in vitro release of amphotericin from cement beads containing 7.5% amphotericin. Following polymerization, 3.3% of the initially loaded amphotericin B was detected. The peak mean concentration eluted from the bone cement was 0.33 µg/mL at 8 hours. The AUC0-24 was 2.79 µg/mL/h; 0.20% of the amphotericin B was released. In conclusion, amphotericin B is released from bone cement at a clinically useful concentration.