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.

Short Term Complications in Geriatric Ankle Fractures Using a Protocolized Approach to Surgical Treatment: Is Early Weight Bearing Safe?

Background: Surgical management of geriatric ankle fractures requires unique considerations in addressing operative risks. Prior studies have reached varying conclusions regarding optimal treatment strategies. The primary aim of this study was to determine if surgical fixation following a predetermined treatment protocol was safe and effective. The secondary aim was to determine if immediate weight bearing as tolerated (IWBAT) in a subset of patients was safe or conferred any short-term benefits. Methods: This retrospective study included all patients over the age 65 treated surgically for an ankle fracture by a single surgeon over a five-year period. A protocol was used including: augmented fixation techniques, IWBAT for select patients, and specific strategies to minimize soft tissue damage. Complications associated with operative treatment were analyzed. A subgroup analysis of patients with isolated ankle injuries was carried out to compare patients made IWBAT to patients made non-weight bearing (NWB) postoperatively. Results: Thirty-four patients were included in the study. Fracture types were predominantly OTA 44B2 (18/34, 53%) and 44B3 (8/34, 24%). Union rate was 100%. Augmented fixation techniques were used in 14/34, 41% of patients. Twenty-one of 34, 62% of patients were allowed IWBAT. There were 4 complications, 12%: 1 malunion, 1 superficial infection, and 2 wound dehiscence. Two patients returned to the operating room for removal of hardware and irrigation and debridement. In the subgroup analysis, the IWBAT group was discharged to a rehabilitation facility at a significantly lower rate than the NWB group, 25% (4/16) vs 90% (9/10; p=0.0036). There were no differences in the complication rates between the two groups. Conclusion: Acceptable outcomes can be reliably obtained when following a standardized approach to geriatric ankle fracture management. In addition, immediate weight bearing in select patients does not seem to increase complications and may benefit patients by increasing rate of discharge to home.Level of Evidence: IV.