Is Vancomycin-only Prophylaxis for Patients With Penicillin Allergy Associated With Increased Risk of Infection After Arthroplasty?

BACKGROUND: Preoperative antibiotic prophylaxis remains one of the most important strategies for prevention of postoperative infection. In patients with penicillin allergy, alternative medications such as vancomycin are often used despite reduced antimicrobial coverage and recent literature questioning the efficacy of vancomycin monotherapy. QUESTIONS/PURPOSES: (1) Are patients who receive vancomycin alone for penicillin allergy at greater odds of developing surgical site infection (SSI) as compared with patients who receive cefazolin for prophylaxis before total joint arthroplasty (TJA) without a patient-reported allergy? (2) What organism profile is associated with vancomycin monotherapy? METHODS: We performed a retrospective study of 10,391 primary TJAs performed between 2005 and 2014 at two institutions with a minimum of 1-year followup. Patients reporting penicillin or cephalosporin allergy were electronically queried from the anesthesia note. The odds of deep SSI and causative organisms were compared using multivariate analysis between ß-lactam-allergic patients receiving vancomycin and nonallergic patients receiving cefazolin. RESULTS: After controlling for potential confounders, including comorbidities, we found that vancomycin alone did not affect the odds of deep SSI development (adjusted odds ratio [OR], 0.98; 95% confidence interval [CI], 0.67-1.43; p = 0.907). Although the overall odds of deep SSI were not different for patients receiving vancomycin versus cefazolin, we found that vancomycin was associated with a reduced risk of infection with Gram-positive organisms (adjusted OR, 0.25 [CI, 0.10-0.62]; p = 0.003) and antibiotic-resistant organisms (adjusted OR, 0.10 [CI, 0.01-0.88]; p = 0.038). Vancomycin also demonstrated an increased risk of Gram-negative infection in bivariate analysis (OR, 2.42 [CI, 1.01-5.82]; p = 0.049) compared to cefazolin. CONCLUSIONS: With the numbers available, vancomycin alone during elective primary TJA does not seem to result in a higher rate of subsequent deep SSI. However, patients who received vancomycin alone demonstrated reduced odds of Gram-positive organisms and methicillin-resistant Staphylococcus aureus. Vancomycin monotherapy can be used without increasing the risk of deep SSI; however, it should only be used in patients who require vancomycin, eg, anaphylactic reactions to penicillin resulting from the potential for the emergence of organism resistance and nephrotoxicity. Future studies are needed that use registry and large database studies to refute or confirm the preliminary findings of this study and determine if vancomycin monotherapy influences the risk of periprosthetic joint infection. LEVEL OF EVIDENCE: Level III, therapeutic study.

Complications of high-energy bicondylar tibial plateau fractures treated with dual plating through 2 incisions.

OBJECTIVES: To characterize the rate of complications after operative fixation of bicondylar (OTA/AO 41-C) tibial plateau fractures and to evaluate the contribution of common risk factors. DESIGN: Retrospective review. SETTING: Level 1 regional trauma center. PATIENTS/PARTICIPANTS: One hundred thirty-eight patients older than 18 years with 140 bicondylar tibial plateau fractures were participated in this study. INTERVENTION: Open reduction and internal fixation using medial and lateral plate construct through 2 incisions. MAIN OUTCOME MEASUREMENTS: Development of a deep infection or a nonunion. RESULTS: The overall major complication rate was 27.9%: 23.6% deep infection and 10.0% nonunion. Open fractures were associated with a higher rate of infection: 43.8% versus 21.0% for closed injuries (odds ratio = 2.96, P = 0.05). Fasciotomy closure before definitive fixation was associated with significantly fewer deep infections compared with internal fixation with open fasciotomy wounds: 11.8% versus 50.0% (odds ratio = 7.5, P = 0.05). The presence of compartment syndrome, tobacco use, diabetes, and timing of surgery had no statistically significant association on the rate of infection or nonunion. CONCLUSIONS: Nonunion and deep infections occur commonly after staged open reduction and internal fixation of high-energy tibial plateau fractures. Open fractures and open fasciotomy wounds at the time of internal fixation are associated with higher rates of infection. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The PA-TM-RING protein RING finger protein 13 is an endosomal integral membrane E3 ubiquitin ligase whose RING finger domain is released to the cytoplasm by proteolysis.

PA-TM-RING proteins have an N-terminal protease-associated domain, a structure found in numerous proteases and implicated in protein binding, and C-terminal RING finger and PEST domains. Homologous proteins include GRAIL (gene related to anergy in leukocytes), which controls T-cell anergy, and AtRMR1 (receptor homology region-transmembrane domain-RING-H2 motif protein), a plant protein storage vacuole sorting receptor. Another family member, chicken RING zinc finger (C-RZF), was identified as being upregulated in embryonic chicken brain cells grown in the presence of tenascin-C. Despite algorithm predictions that the cDNA encodes a signal peptide and transmembrane domain, the protein was found in the nucleus. We showed that RING finger protein 13 (RNF13), the murine homolog of C-RZF, is a type I integral membrane protein localized in the endosomal/lysosomal system. By quantitative real-time RT-PCR analysis, we demonstrated that expression of RNF13 is increased in adult relative to embryonic mouse tissues and is upregulated in B35 neuroblastoma cells stimulated to undergo neurite outgrowth. We found that RNF13 is very labile, being subject to extensive proteolysis that releases both the protein-associated domain and the RING domain from the membrane. By analyzing microsomes, we showed that the ectodomain is shed into the lumen of vesicles, whereas the C-terminal half, which possesses the RING finger, is released to the cytoplasm. This C-terminal fragment of RNF13 has the ability to mediate ubiquitination. Proteolytic release of RNF13 from a membrane anchor thus provides unique spatial and temporal regulation that has not been previously described for an endosomal E3 ubiquitin ligase.