Fracture-Associated Microbiome and Persistent Nonunion: Next-Generation Sequencing Reveals New Findings.

INTRODUCTION: Fracture nonunion remains a devastating complication and may occur for several reasons, though the microbial contribution remains poorly estimated. Next-generation sequencing (NGS) techniques, including 16S rRNA gene profiling, are capable of rapid bacterial detection within clinical specimens. Nonunion cases may harbor microbes that escape detection by conventional culture methods that contribute to persistence. Our aim was to investigate the application of NGS pathogen detection to nonunion diagnosis. METHODS: In this prospective multicenter study, samples were collected from 54 patients undergoing open surgical intervention for preexisting long-bone nonunion (n = 37) and control patients undergoing fixation of an acute fracture (n = 17). Intraoperative specimens were sent for dual culture and 16S rRNA gene-based microbial profiling. Patients were followed for evidence of fracture healing, whereas patients not healed at follow-up were considered persistent nonunion. Comparative analyses aimed to determine whether microbial NGS diagnostics could discriminate between nounions that healed during follow-up versus persistent nonunion. RESULTS: Positive NGS detection was significantly correlated with persistent nonunion, positive in 77% more cases than traditional culture. Nonunion cases were observed to have significantly increased diversity and altered bacterial profiles from control cases. DISCUSSION: NGS seems to be a useful adjunct in identification of organisms that may contribute to nonunion. Our findings suggest that the fracture-associated microbiome may be a significant risk factor for persistent nonunion. Ongoing work aims to determine the clinical implications of isolated organisms detected by sequencing and to identify robust microbial predictors of nonunion outcomes. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Validation of the AO Spine Sacral Classification System: Reliability Among Surgeons Worldwide.

OBJECTIVES: To (1) demonstrate that the AO Spine Sacral Classification System can be reliably applied by general orthopaedic surgeons and subspecialists universally around the world and (2) delineate those injury subtypes that are most difficult to classify reliably to refine the classification before evaluating clinical outcomes. DESIGN: Agreement study. SETTING: All-level trauma centers, worldwide. PARTICIPANTS: One hundred seventy-two members of the AO Trauma and AO Spine community. INTERVENTION: The AO Sacral Classification System was applied by each surgeon to 26 cases in 2 independent assessments performed 3 weeks apart. MAIN OUTCOME MEASUREMENTS: Interobserver reliability and intraobserver reproducibility. RESULTS: A total of 8097 case assessments were performed. The kappa coefficient for interobserver agreement for all cases was 0.72/0.75 (assessment 1/assessment 2), representing substantial reliability. When comparing classification grading (A/B/C) regardless of subtype, the kappa coefficient was 0.84/0.85, corresponding to excellent reliability. The kappa coefficients for interobserver reliability were 0.95/0.93 for type A fractures, 0.78/0.79 for type B fractures, and 0.80/0.83 for type C fractures. The overall kappa statistic for intraobserver reliability was 0.82 (range 0.18-1.00), representing excellent reproducibility. When only evaluating morphology type (A/B/C), the average kappa value was 0.87 (range 0.18-1.00), representing excellent reproducibility. CONCLUSION: The AO Spine Sacral Classification System is universally reliable among general orthopaedic surgeons and subspecialists worldwide, with substantial interobserver and excellent intraobserver reliability.

The Use of Integra Dermal Regeneration Templates and Cortical Bone Fenestrations over Exposed Tibia.

We present the case of an 86-year-old woman who suffered full-thickness soft tissue loss secondary to degloving injury to the lower left limb, resulting in an exposed tibia. This patient underwent drilling to create artificial fenestrations in the cortical bone followed by placement of Integra dermal regeneration template. The technique of drilling fenestrations to expose underlying vasculature of cortical bone has not previously been described in its relationship with Integra dermal regeneration templates in large degloving injuries of the lower limb. This technique enabled us to perform earlier skin grafting and ultimately resulted in complete and timely wound closure. We present this case as a comparable alternative treatment in cases of reconstructive surgery secondary to severe burns or trauma to reduce the time required for successful wound closure over exposed bone in full-thickness tissue loss injuries of the lower limb.

Hardware Removal Due to Infection after Open Reduction and Internal Fixation: Trends and Predictors.

BACKGROUND: Little is known about trends and predictors of hardware related infection following open reduction and internal fixation (ORIF) of extremity fractures, one of the major causes of failure following ORIF. The present study was designed and conducted to determine trends and predictors of infection-related hardware removal following ORIF of extremities using a nationally representative database. METHODS: We used Nationwide Inpatient Sample data from 2002 to 2011 to identify cases of ORIF following upper and lower extremity fractures, as well as cases that underwent infection-related hardware removal following ORIF. Multivariate analysis was performed to identify independent predictors of infection-related hardware removal, controlling for patient demographics and comorbidities, hospital characteristics, site of fracture, and year. RESULTS: For all ORIF procedures, the highest rate of hardware removal related to infection was observed in tarsal fractures (5.56%), followed by tibial (3.65%) and carpal (3.37%) fractures. Hardware removal rates due to infection increased in all fractures except radial/ulnar fractures. Tarsal fractures(odds ratio (OR)=1.06, 95% confidence interval (CI): 1.04-1.09, P<0.001), tibial fractures (OR=1.04, 95% CI: 1.03-1.06, P<0.001) and those patients with diabetes mellitus (OR=2.64, 95% CI: 2.46-2.84, P<0.001), liver disease (OR=2.04, 95% CI: 1.84- 2.26, P<0.001), and rheumatoid arthritis (OR=2.06, 95% CI: 1.88-2.25 P<0.001) were the main predictors of infection-related removals; females were less likely to undergo removal due to infection (OR= 0.61, 95% CI: 0.59-0.63 P<0.001). CONCLUSIONS: Hardware removal rates due to infection increased in all fractures except radial/ulnar fractures. Diabetes, liver disease, and rheumatoid arthritis were important predictors of infection-related hardware removal. The study identified some risk factors for hardwarerelated infection following ORIF, such as diabetes, liver disease, and rheumatoid arthritis, that should be studied further in an attempt to implement strategies to reduce rate of infection following ORIF.

Interobserver Variability in the Measurement of Lower Leg Compartment Pressures.

OBJECTIVES: To determine whether interobserver technical variations and errors in the measurement of compartment pressures may affect measurement accuracy. METHODS: Four above-knee cadaveric specimens were used to create a consistent model of lower leg compartment syndrome. Thirty-eight physicians examined the limbs and measured 4 compartment pressures using the Intra-Compartmental Pressure Monitor (Stryker Orthopaedics). They were observed for correct assembly and use of the monitor. Measurements obtained were compared with known pressures. RESULTS: Of the total number of compartment measurements, 31% were made using the correct technique, 39% were made with lesser errors in technique, and 30% were made with catastrophic errors. Only 60% of measurements made with the correct technique were within 5 mm Hg of the standard pressure. Accuracy dropped to 42% for measurements taken with small errors in technique and 22% when a catastrophic error was committed. CONCLUSIONS: Variations in use of a commercially available pressure monitor exist, and errors are common. Proper use improved accuracy, but even with proper technique, 40% of the measurements were >5 mm Hg from the actual pressure. Based on our data, measurement accuracy with this device should be questioned and viewed within a range. Regular review and education of technique is strongly recommended.