Eight-year follow-up after staged limb salvage using bone transport and delayed hexapod-assisted deformity correction for chronic MRSA-related proximal tibial nonunion after failed intramedullary nailing: a case report

Introduction and importance: Chronic infected tibial nonunion is not uncommon but remains a challenging reconstructive problem, particularly when infection, bone loss, deformity, failed fixation, and compromised soft tissue coexist. Although treatment principles are well-established, their sequencing may be important in complex cases requiring biological reconstruction and deformity correction. Case presentation: A 39-year-old man was referred with severe weight-bearing pain and walking disability 1 year after intramedullary nailing for a Gustilo type IIIA open proximal tibial fracture. Radiographs showed implant failure and varus malalignment, and computed tomography demonstrated a cavitary nonunion with posterior cortical disruption. Deep intraoperative cultures yielded methicillin-resistant Staphylococcus aureus (MRSA). Clinical discussion: Treatment consisted of implant removal, radical debridement, an approximately 8-cm segmental resection, temporary local antibiotic delivery, 8 weeks of intravenous daptomycin, and bone transport using circular external fixation. Infection control and biological reconstruction were prioritized before definitive correction of residual deformity, which was deferred until after docking and subsequently performed using a hexapod system. At 8-year follow-up, the patient maintained solid union and alignment, with normalized inflammatory markers and no recurrent infection, limb-length discrepancy, or reoperation. He achieved pain-free full weight-bearing, a knee range of motion of 120°/0°, an International Knee Documentation Committee score of 97, a Tegner activity level of 6, and return to recreational sports. Conclusion: This case illustrates staged sequencing of established reconstructive principles in complex MRSA-related proximal tibial nonunion. Staged bone transport followed by delayed hexapod-assisted correction may provide durable limb salvage and long-term function in selected cases.