Is Preoperative Identification of the Infecting Organism Essential Before Single-Stage Revision Hip Arthroplasty for Periprosthetic Infection?

BACKGROUND: It is commonly stated that identification of the infecting organism is a prerequisite to single-stage revision arthroplasty of the hip for deep infection. We have performed single-stage revision in a series of patients where the organism was not identified preoperatively. The aim of this study is to investigate whether the rate of infection eradication following single-stage revision was affected by preoperative knowledge of the infecting organism. METHODS: We identified all patients who had undergone a single-stage revision for a deep infection at our hospital between 2006 and 2015. One hundred five patients were assigned into 2 groups based upon whether the infecting organism had been identified preoperatively (group A = 28) or not (group B = 77). RESULTS: The reinfection rates were 3.6% in group A and 9.1% for group B (P = .679). Re-revision rates were 7.1% and 9.1%, respectively (P = 1.00). Overall, the implant survival rate at 6 years was 87.9% (95% confidence interval, 97.4-78.4). In group B, preoperative aspiration was performed in 36.4% (28/77) of cases. Staphylococci species were the predominant causative organisms, with gram-negative involvement in 19.0% (20/105) of cases. CONCLUSION: The rate of infection eradication and overall survivorship with single-stage revision was similar in our series to that reported in the literature. While desirable, we did not find identification of the infecting organism before surgery influenced the outcome. Given the functional and economic benefits of single-stage revision, we suggest that failure to identify an organism is not an absolute contraindication to this approach.

The Emergence of Zoonotic Onchocerca lupi Infection in the United States--A Case-Series.

This case-series describes the 6 human infections with Onchocerca lupi, a parasite known to infect cats and dogs, that have been identified in the United States since 2013. Unlike cases reported outside the country, the American patients have not had subconjunctival nodules but have manifested more invasive disease (eg, spinal, orbital, and subdermal nodules). Diagnosis remains challenging in the absence of a serologic test. Treatment should be guided by what is done for Onchocerca volvulus as there are no data for O. lupi. Available evidence suggests that there may be transmission in southwestern United States, but the risk of transmission to humans is not known. Research is needed to better define the burden of disease in the United States and develop appropriately-targeted prevention strategies.

The effect of surface modification and aprotinin on cellular injury during simulated cardiopulmonary bypass.

Cardiopulmonary bypass (CPB) elicits derangements to the formed elements of blood because of the physical stresses of extracorporeal flow. Methods of reducing the impact of CPB include circuit surface modification and pharmacological supplementation. The purpose of this study was to examine the effects of aprotinin in combination with surface modification during simulated CPB. Fresh whole bovine blood was used to prime standard CPB circuits divided into four groups (N = 3): control (CTR), aprotinin 300 KIU/mL (APR), Poly (2-methoxyethylacrylate) coating (PMEA), and APR with PMEA (APR-PMEA). Physical stresses included venous reservoir negative pressure (-85 mmHg), arterial line pressure of 150 mmHg at 5 LPM, and air-blood interface, applied over a 90-minute period. Samples were drawn at the following times: 0, 10, 45, and 90 minutes. Endpoints included platelet count (PLT), plasma-free hemoglobin (PFHb), and thromboelastography (TEG). PLT did not change (138.9 +/- 15.0 vs. 102.9 +/- 21.0, p = ns) throughout the 90-minute experimental periods in any group. PFHb increased significantly (mean of 19- fold) throughout the experiment, but was not affected by any treatment. The TEG index declined in the CTR (3.6 +/- 0.4 vs. -16.2 +/- 2.9, p < .0003), PMEA (5.9 +/- 0.8 vs. -2.7 +/- 3.8, p < .02), and APR-PMEA (4.6 +/- 1.0 vs. -2.8 +/- 0.3 p < .0003) groups, but not in the APR group (3.6 +/- 2.2 vs. -1.3 +/- 3.3 p = .10). In conclusion, neither APR nor PMEA had an effect on either red cell hemolysis or PLT, but APR treatment alone significantly attenuated the derangements in coagulation induced in this extracorporeal model.