Previously unexplored etiology for femoral head necrosis: Metagenomics detects no pathogens in necrotic femoral head tissue

BACKGROUND Osteonecrosis of the femoral head (ONFH) is a frequent and refractory disease whose pathogenesis has not yet been elucidated. Infection and other factors that reduce the local blood supply can lead to bone necrosis. AIM To aim of this study was to assess the relationship of ONFH with bone infection by use of metagenomic sequencing. METHODS Twelve patients with idiopathic ONFH and 12 comparable controls who were undergoing hip arthroplasty were followed up in parallel. Necrotic femoral head specimens were collected for bacterial and fungal cultures using standard methods. Bone specimens were subjected to preliminary processing, and metagenomics sequencing of microorganisms was performed. A one-way analysis of variance was used to compare bacterial species in the two groups. RESULTS Bacterial and fungal cultures exhibited no evidence of microbial growth in all isolated necrotic femoral head tissues. We thus performed metagenomic sequencing and classified the species as suspected pathogens or suspected background microorganisms based on known bacterial pathogenicity. There was no evidence of viruses, fungi, parasites, M. tuberculosis complex, or mycoplasma chlamydia. There were also no significant differences in suspected pathogens or suspected background microorganisms (P > 0.05). CONCLUSION Although we found no pathogens specific for ONFH in necrotic femoral head tissue, our research provides a foundation for future research on the metagenomics of bone pathogens.