Mechanisms of Chronic Post-Traumatic Osteomyelitis Recurrence Following Surgical Management: A Microbiological, Genomic, and Immunological Investigation in Nigerian Tertiary Hospitals

Chronic osteomyelitis following open fractures remains one of the most intractable conditions in Nigerian orthopaedic practice, characterised by high recurrence rates after surgical debridement and prolonged antibiotic therapy. The mechanisms driving recurrence, particularly bacterial biofilm persistence, host immune evasion, and inadequate bone perfusion, are incompletely understood in the Nigerian clinical context. This multi-disciplinary study investigates the microbiological, genomic, and immunological determinants of recurrent chronic post-traumatic osteomyelitis in 150 adults presenting with recurrence after surgical management at UNTH Enugu, LUTH Lagos, and AKTH Kano over a three-year period. Bone and wound biopsy specimens will undergo bacterial culture, whole-genome sequencing of isolates to characterise virulence genes and antibiotic resistance determinants, and biofilm quantification using confocal laser scanning microscopy. Immunological analysis will include quantification of serum cytokines (IL-6, IL-17A, TNF-alpha, IL-10) and histological assessment of local innate immune cell populations. Genomic epidemiology will determine whether recurrences represent relapses from the original infecting strain or reinfections. Multi-level regression will identify microbiological and immunological predictors of recurrence. The study hypothesises that biofilm-producing Staphylococcus aureus with toxin-antitoxin persistence mechanisms are the dominant cause of relapse, while immunosuppressed states impair bacterial clearance. This original mechanistic investigation will inform precision antibiotic and surgical strategies for osteomyelitis recurrence in Nigeria. Keywords: chronic osteomyelitis, biofilm, recurrence, whole-genome sequencing, bacterial persistence.