Effects of roadside memorials on drivers' risk perception and eye movements.

Road crashes are a leading cause of death worldwide. In many countries, it is common to see spontaneous roadside memorials constructed in response to road fatalities. These memorials are controversial and are explicitly banned in many jurisdictions. Advocates argue that the presence of memorials improves safety by making other drivers aware of an especially dangerous road where others have died, whereas opponents argue that they are distracting and decrease safety by diverting drivers' attention away from the road. However, there has been almost no research examining the effects of roadside memorials on road user behavior and safety. In this study, 40 drivers viewed videos of road scenes with and without memorials, to examine how the presence of roadside memorials influences drivers' attentional allocation (indicated by eye movements to the roadside area) and safety-related behaviors (indicated by perceived risk ratings and preferred travel speeds for the road). The findings indicate memorials do capture visual attention, as participants were more likely to fixate on memorials compared with a comparison object placed on the roadside. However, fixations on the memorials, and to the roadside area in general, were relatively brief. The presence of memorials did not affect perceived risk and did not produce a clear systematic effect on preferred travel speed. Nearly all drivers in our study supported permitting roadside memorials, but a small number strongly opposed memorials on the belief they are distracting and/or distressing. PREREGISTRATION DETAILS: This study was preregistered with Cognitive Research: Principles and Implications and received in-principle acceptance on 4 March 2018. The preregistered protocol is available here: https://doi.org/10.6084/m9.figshare.6181937 .

Performance characteristics of broth-only cultures after revision total joint arthroplasty.

BACKGROUND: Surgeons frequently obtain intraoperative cultures at the time of revision total joint arthroplasty. The use of broth or liquid medium before applying the sample to the agar medium may be associated with contamination and false-positive cultures; however, the degree to which this is the case is not known. QUESTIONS/PURPOSES: We (1) calculated the performance characteristics of broth-only cultures (sensitivity, specificity, positive predictive value, and negative predictive value) and (2) characterized the organisms identified in broth to determine whether a specific organism showed increased proclivity for true-positive periprosthetic joint infection (PJI). METHODS: A single-institution retrospective chart review was performed on 257 revision total joint arthroplasties from 2009 through 2010. One hundred ninety (74%) had cultures for review. All culture results, as well as treatment, if any, were documented and patients were followed for a minimum of 1 year for evidence of PJI. Cultures were measured as either positive from the broth only or broth negative. The true diagnosis of infection was determined by the Musculoskeletal Infection Society criteria during the preoperative workup or postoperatively at 1 year for purposes of calculating the performance characteristics of the broth-only culture. RESULTS: The sensitivity, specificity, positive predictive value, and negative predictive value were 19%, 88%, 13%, and 92%, respectively. The most common organism identified was coagulase-negative Staphylococcus (16 of 24 cases, 67%). Coagulase-negative Staphylococcus was present in all three true-positive cases; however, it was also found in 13 of the false-positive cases. CONCLUSIONS: The broth-only positive cultures showed poor sensitivity and positive predictive value but good specificity and negative predictive value. The good specificity indicates that it can help to rule in the presence of PJI; however, the poor sensitivity makes broth-only culture an unreliable screening test. We recommend that broth-only culture results be carefully scrutinized and decisions on the diagnosis and treatment of infection should be based specifically on the Musculoskeletal Infection Society criteria. LEVEL OF EVIDENCE: Level IV, diagnostic study. See Instructions for Authors for a complete description of levels of evidence.

Is it time to include vancomycin for routine perioperative antibiotic prophylaxis in total joint arthroplasty patients?

In an effort to reduce methicillin-resistant Staphylococcus aureus (MRSA) and overall periprosthetic joint infections (PJI), we switched the perioperative prophylactic antibiotic during total knee arthroplasty and total hip arthroplasty from cefazolin to vancomycin in June 2008. We retrospectively reviewed the total and MRSA PJI in 5036 primary total joint arthroplasties, as well as the cure rate of PJI from January 2006 to June 2008 (Ancef Period) and June 2008 to December 2010 (Vanco Period). With vancomycin, total PJI was significantly reduced (1.0%-0.5%) and MRSA PJI (0.23%-0.07%). Periprosthetic joint infections that occurred were more successfully treated with irrigation and debridement only, not requiring spacer (76.9% vs 22.2%). The use of vancomycin as the perioperative prophylactic antibiotic for primary total joint arthroplasties appeared to be effective in decreasing the rate of PJI and may result, when they occur, in infections with less virulent organisms.