Efficacy of Cefazolin versus Ceftriaxone for Extremity Open Fracture Management at a Level 1 Trauma Center.

Background: Antibiotic agents have been shown to improve outcomes in open extremity fractures. The first-generation cephalosporins, which are used most often, are often under-dosed based on weight and recommended frequency. Ceftriaxone offers a broader coverage and a decreased frequency of administration. Our institution began utilizing ceftriaxone for open fracture management in 2017 to address those concerns. Objective: To examine the efficacy of cefazolin versus ceftriaxone for open fracture management of extremity trauma. Patients and Methods: Retrospective study from 2015-2019 of patients who sustained open extremity fractures. Patients were stratified by antibiotic administered and Gustilo-Anderson grade. Outcomes included non-union/malunion, superficial surgical site infection (SSI), deep SSI, osteomyelitis, re-operation after index hospital visit, re-admission due to prior injury, limb loss, and death. Subgroup analysis stratified each antibiotic group by Gustilo-Anderson grade 1 or 2 and grade 3. Results: Data was collected from 2015 to 2019. Of the 1,149 patients, 619 patients met inclusion criteria. Three hundred fifty-five patients received cefazolin and 264 patients received ceftriaxone. There were no statistically significant differences between groups on specified outcomes. No statistically significant differences existed during subgroup analysis for the specified outcomes. Multivariable analysis demonstrated increased Gustilo-Anderson grade increased risk of infectious outcome. Conclusions: Ceftriaxone is a safe and effective alternative for open fracture extremity management that offers the advantage of 24-hour dosing and single antibiotic coverage for grade 3 open fractures. It does not increase infectious complications and offers benefits of resource efficiency.

Efficacy of Postoperative Oral Antibiotics in Foot and Ankle Surgery.

BACKGROUND: Preoperative oral antibiotic use in patients undergoing foot and ankle surgery is standard practice, but no consensus has been reached regarding the efficacy of postoperative oral antibiotics. The purpose of this study was to determine whether postoperative oral antibiotics reduce the rate of surgical site infections (SSIs) in patients, with and without comorbidities, undergoing foot and ankle surgery. METHODS: A retrospective chart review was conducted identifying patients who underwent foot and ankle surgery by 4 fellowship-trained, foot and ankle orthopaedic surgeons between January 1, 2015, and January 1, 2019. Patients were divided into 2 groups: those who received postoperative oral antibiotics (group 1) and those who did not (group 2). Two surgeons routinely prescribed postoperative oral antibiotics, and 2 did not. Demographics, comorbidities, and procedure complexity based on surgical site and Current Procedural Terminology code were recorded from the charts. The primary outcome was postoperative infection (superficial or deep) within 6 months after surgery. Patients with antibiotic use prior to surgery, preoperative infection, or lack of follow-up >6 weeks were excluded. Multivariate logistic regression modeling was used to analyze differences in infection rate and severity. RESULTS: Chart review identified 3631 patients, 1227 of whom did not receive postoperative oral antibiotics whereas 2394 patients did. Routine postoperative oral antibiotic use did not significantly affect postoperative infection rates or severity. However, all covariates studied (diabetes, hypertension, obesity, tobacco use, alcohol use, rheumatoid conditions, and age) influenced postoperative infection rates and severity. CONCLUSION: The results of this study indicate that postoperative oral antibiotics are not associated with differences in infection rates or severity. We do not recommend routine use in foot and ankle surgery.

Characterizing protein conformations by correlation analysis of coarse-grained contact matrices.

We have developed a method to capture the essential conformational dynamics of folded biopolymers using statistical analysis of coarse-grained segment-segment contacts. Previously, the residue-residue contact analysis of simulation trajectories was successfully applied to the detection of conformational switching motions in biomolecular complexes. However, the application to large protein systems (larger than 1000 amino acid residues) is challenging using the description of residue contacts. Also, the residue-based method cannot be used to compare proteins with different sequences. To expand the scope of the method, we have tested several coarse-graining schemes that group a collection of consecutive residues into a segment. The definition of these segments may be derived from structural and sequence information, while the interaction strength of the coarse-grained segment-segment contacts is a function of the residue-residue contacts. We then perform covariance calculations on these coarse-grained contact matrices. We monitored how well the principal components of the contact matrices is preserved using various rendering functions. The new method was demonstrated to assist the reduction of the degrees of freedom for describing the conformation space, and it potentially allows for the analysis of a system that is approximately tenfold larger compared with the corresponding residue contact-based method. This method can also render a family of similar proteins into the same conformational space, and thus can be used to compare the structures of proteins with different sequences.