Is There a Seasonal Influence on Orthopaedic Surgical Wound Infection Rates?

Postoperative surgical wound infections are a significant cause of morbidity in orthopaedic surgical cases. To date, there has been no large, single-institution study evaluating orthopaedic surgical wound infection rates and their correlation with seasonality. The hypothesis of this study was that there would be more infections in the warmer months of the year. A retrospective review of all orthopaedic surgery cases at the authors' institution from 1992 to 2012 was performed of all patients with postoperative wound infections. Patients were placed into two groups on the basis of the date of initial surgical fixation: those occurring in warm months (May-September) and those occurring in cold months (October-April). From July 2010 to June 2012, there was not a statistically significant increase in total infection rate during the months of May to September compared with the months of October to April (0.8% and 0.6%, respectively; p = .131). The hypothesis was rejected: there was no significant increase in post-operative infections during the warmer months. Although previous studies have demonstrated such an increase, the results of this study, which were from a much larger cohort, disagree.

"Nailable" Does Not Always Mean Reducible in Distal Femur Fractures: Arthroplasty Component and Nail Design Matter.

Distal femur fractures above a total knee arthroplasty (TKA) are challenging. These fractures can be fixed with a retrograde intramedullary nail (rIMN), but the design of the femoral component of the TKA influences the starting point for an rIMN. We performed a biomechanical study to evaluate how different TKA components influence the starting point for an rIMN and how that can lead to a deformity in the sagittal plane. We simulated a distal femur fracture with three different arthroplasty components. We used three different implants to simulate fracture reduction and measured the resultant sagittal plane deformity. Low and moderate femoral component ratio (FCR) design components were able to maintain fracture alignment within 5° of anatomic. High FCR component (more posterior starting point) sagittal plane deformities of up to 15° were observed with both the straight and medium Herzog bend nails, which was statistically significant (P<.001). Use of a high Herzog bend nail decreased the deformity by an average of 6°, which was statistically significant (P<.001). There is variability in how the TKA design affects the starting point and thus the sagittal plane alignment after fixation. This study helps quantify the effect of arthroplasty component design on fracture alignment. [Orthopedics. 2023;46(1):35-38.].

Surface-grafted zwitterionic polymers improve the efficacy of a single antibiotic injection in suppressing S. aureus periprosthetic infections.

Implant-associated bacterial infections are difficult to treat due to the tendency of biofilm formation on implant surfaces, which protects embedded pathogens from host defense and impedes antibiotic penetration, rendering systemic antibiotic injections ineffective. Here, we test the hypothesis that implant coatings that reduce bacterial colonization would make planktonic bacteria within the periprosthetic environment more susceptible to conventional systemic antibiotic treatment. We covalently grafted zwitterionic polymer brushes poly(sulfobetaine methacryate) from Ti6Al4V surface to increase the substrate surface hydrophilicity and reduce staphylococcus aureus (S. aureus) adhesion. Using a mouse femoral intramedullary (IM) canal infection model, we showed that the anti-fouling coating applied to Ti6Al4V IM implants, when combined with a single vancomycin systemic injection, significantly suppressed both bacterial colonization on implant surfaces and the periprosthetic infections, outperforming either treatment alone. This work supports the hypothesis that grafting anti-fouling polymers to implant surfaces improves the efficacy of systemic antibiotic injections to combat periprosthetic infections.

Significant Suppression of Staphylococcus aureus Colonization on Intramedullary Ti6Al4V Implants Surface-Grafted with Vancomycin-Bearing Polymer Brushes.

Orthopedic implant-associated bacterial infection presents a major health threat due to tendency for periprosthetic bacterial colonization/biofilm formation that protects bacteria from host immune response and conventional antibiotic treatment. Using surface-initiated atom transfer radical polymerization and copper-catalyzed azide-alkyne cycloaddition (CuAAC), alkynylated vancomycin is conjugated to azido-functionalized side chains of polymethacrylates grafted from Ti6Al4V. High-efficiency CuAAC across the substrate is confirmed by complete surface conversion of azides by X-ray photoelectron spectroscopy (XPS) and elemental mapping of changing characteristic elements. The vancomycin-modified surface (Ti-pVAN) significantly reduces in vitro adhesion and colonization of Staphylococcus aureus (S. aureus), a main bacterial pathogen responsible for periprosthetic infection and osteomyelitis, compared to untreated Ti6Al4V, supporting retained antibacterial properties of the covalently conjugated antibiotics. When the surface-modified intramedullary Ti-pVAN pins are inserted into mouse femoral canals infected by bioluminescent Xen29 S. aureus, significantly reduced local bioluminescence along with mitigated blood markers for infection are detected compared to untreated Ti6Al4V pins over 21 days. Ti-pVAN pins retrieved after 21 days are confirmed with ∼20-fold reduction in adherent bacteria counts compared to untreated control, supporting the ability of surface-conjugated vancomycin in inhibiting periprosthetic S. aureus adhesion and colonization.

Moped collisions among patients with revoked drivers' licenses are a significant public health problem: a retrospective cohort study.

Many states do not require a license to operate a moped, defined as a motor vehicle with less than 50-cc engine displacement. These vehicles may therefore serve as a mode of transportation for those who are driving without a license and who may have a history of prior high-risk behavior. We hypothesized that those involved in moped collisions were more likely to have previous convictions for driving while intoxicated (DWI) and other non-DWI offenses than those on conventional motorcycles. At a Level I trauma center, we queried the trauma registry from January 2005 to October 2010 for admissions after motorcycle or moped collisions. Classification of mechanism of injury was verified through chart review. Corrections databases from our state were then reviewed for previous convictions for DWI and other offenses. One thousand seventy-three patients over the study period were involved in motorcycle or moped collisions; 94 were from another state. Of the patients identified from our state, 249 had moped collisions and 730 had motorcycle collisions. Forty-nine per cent (121) of moped drivers had a history of DWI versus only 8 per cent (56) of motorcycle drivers (P ≤ 0.05). Sixty-four per cent (161) of moped drivers were previously convicted of a crime versus 20 per cent (146) of those on motorcycles (P ≤ 0.05). Moped drivers were significantly more likely to have a prior conviction of DWI as well as prior convictions of other crimes, establishing a pattern of disregard for the law. The use of these vehicles without a license likely presents a risk to public safety. Legislation to require licensing before moped operation should be considered.