Risk of Infection Following Gunshot Wound Fractures to the Foot and Ankle: A Multicenter Retrospective Study.

The purpose of this multicenter retrospective chart review was to describe demographics, fracture and wound characteristics, and treatments for foot and/or ankle fractures caused by gunshot wounds (GSWs) and identify factors that increase risk of infection in adults treated at 5 urban level 1 trauma centers in South and Midwest regions of the United States. A total of 244 patients sustained GSW-related fractures of the foot/ankle during 2007-2017, of whom 179 had ≥30 days of follow-up data after the initial injury. Most patients were male (95.1%; 232/244) with an average age of 31.2 years. On average, patients sustained 1.3 GSWs (range 1-5) to the foot/ankle. Most GSWs were categorized as low energy (85.1%; 171/201) and the majority (58.2%; 142/244) had retained bullet fragments. Antibiotics were administered at initial presentation to 78.7% (192/244) of patients and 41.8% (102/244) were managed operatively at the time of initial injury. Nerve injury, vascular injury, and infection were documented in, respectively, 8.6% (21/243), 6.6% (16/243), and 17.2% (42/244) of all cases. Multivariable analysis revealed that high-energy injuries and retained bullet fragments increased the risk of infection by 3-fold (odds ratio 3.09, 95% confidence interval 1.16-8.27, p = .025) and 3.5-fold (OR 3.48, 95% CI1.40-8.67; p = .008), respectively. Side of injury, primary injury region, and vascular injury were not significant predictors of infection risk. Further research should examine whether retained bullet fragments are directly associated with infection risk and support the development of guidelines regarding the management of patients with GSW-related fractures to the ankle/foot.

Contemporary 2-Stage Treatment of Periprosthetic Hip Infection with Evidence-Based Standardized Protocols Yields Excellent Results: Caveats and Recommendations.

BACKGROUND: This study quantified the effectiveness of contemporary and evidence-based standardized 2-stage treatment for periprosthetic hip infection. Findings illustrate potential limitations of criticisms of 2-stage protocols and potential consequences of adopting single-stage protocols before definitive data are available. METHODS: Fifty-four consecutive hips treated with 2-stage resection and reimplantation were retrospectively reviewed. Standardized protocols were adhered to including implant resection, meticulous surgical debridement, antibiotic spacer, 6-week intravenous antibiotics, a 2-week drug holiday, and laboratory assessment of infection eradication before reimplantation. After reimplantation, patients were placed on prophylactic intravenous antibiotics until discharge and discharged on oral antibiotics for a minimum of 7 days until intraoperative cultures were final. Successful treatment was defined per Delphi-based International Multidisciplinary Consensus. RESULTS: The overall treatment success rate was 95.7% (44 of 46 cases) with mean infection-free survivorship of 67.2 (range, 23.8-106.4) months. Success rates were 100% for early and acute hematogenous infections regardless of host type and 100% for chronic infections in uncompromised hosts. 95% (19/20) of chronic infections in compromised hosts and 83.3% (5/6) of chronic infections in significantly compromised hosts were successfully treated. About 4% of primary hips and 20% of revision hips required repeat debridement and spacer exchange after initial resection. No patients died because of treatment. CONCLUSION: Details from this consecutive series of patients undergoing 2-stage treatment for hip infection suggest that some criticisms of 2-stage treatment as well as some arguments in support of single-stage treatment may be overstated. Promotion and uncritical adoption of single-stage treatment protocols are discouraged until further and more definitive data exist.

Loss of Nmp4 optimizes osteogenic metabolism and secretion to enhance bone quality.

A goal of osteoporosis therapy is to restore lost bone with structurally sound tissue. Mice lacking the transcription factor nuclear matrix protein 4 (Nmp4, Zfp384, Ciz, ZNF384) respond to several classes of osteoporosis drugs with enhanced bone formation compared with wild-type (WT) animals. Nmp4-/- mesenchymal stem/progenitor cells (MSPCs) exhibit an accelerated and enhanced mineralization during osteoblast differentiation. To address the mechanisms underlying this hyperanabolic phenotype, we carried out RNA-sequencing and molecular and cellular analyses of WT and Nmp4-/- MSPCs during osteogenesis to define pathways and mechanisms associated with elevated matrix production. We determined that Nmp4 has a broad impact on the transcriptome during osteogenic differentiation, contributing to the expression of over 5,000 genes. Phenotypic anchoring of transcriptional data was performed for the hypothesis-testing arm through analysis of cell metabolism, protein synthesis and secretion, and bone material properties. Mechanistic studies confirmed that Nmp4-/- MSPCs exhibited an enhanced capacity for glycolytic conversion: a key step in bone anabolism. Nmp4-/- cells showed elevated collagen translation and secretion. The expression of matrix genes that contribute to bone material-level mechanical properties was elevated in Nmp4-/- cells, an observation that was supported by biomechanical testing of bone samples from Nmp4-/- and WT mice. We conclude that loss of Nmp4 increases the magnitude of glycolysis upon the metabolic switch, which fuels the conversion of the osteoblast into a super-secretor of matrix resulting in more bone with improvements in intrinsic quality.