Ankle arthrodesis following bone transport as a definitive limb salvage strategy after multiple failed microsurgical reconstructions for infected tibial pilon fracture nonunion: a case report

Reconstruction of large segmental tibial bone defects remains one of the most challenging problems in orthopedic trauma surgery, particularly when complicated by infection and soft tissue compromise. Various techniques, including vascularized fibular grafting, induced membrane formation, and bone transport, have been described for limb salvage in such complex situations. Bone transport based on distraction osteogenesis enables biological reconstruction of bone defects while simultaneously improving the local biological environment.

A 39-year-old male construction worker sustained an open comminuted tibial pilon fracture after falling approximately 5 meters from a roof. Despite multiple surgical interventions at previous institutions, including vascularized fibular grafting, anterolateral thigh flap reconstruction, and reverse sural artery flap reconstruction, the patient developed infected nonunion with severe distal tibial bone loss and a medial ankle soft tissue defect. A total of 19 procedures were performed, and below-knee amputation was recommended before referral.

The patient was referred to our institution for limb salvage. Because the distal tibial articular surface had insufficient bone stock for joint preservation and local vascular conditions were considered to be severely compromised after repeated failed microsurgical reconstructions, ankle arthrodesis following bone transport was planned. Approximately 10 cm of infected bone was resected, and an antibiotic-loaded hydroxyapatite spacer containing vancomycin was inserted. Bone transport was initiated after proximal tibial corticotomy at a rate of 1 mm per day in four increments following a 1-week latency period. During transport, the soft tissue defect gradually epithelialized without additional flap reconstruction. Docking was achieved at 4 months, followed by autologous cancellous bone grafting, and the external fixator was removed 6 months after docking.

Infection was controlled with systemic antibiotics, and soft tissue healing was achieved using negative pressure wound therapy followed by fibroblast growth factor application. No recurrence of infection was observed, and at 8-year follow-up, the patient had returned to full-time construction work with a Japanese Society for Surgery of the Foot (JSSF) score of 88 points and a visual analogue scale (VAS) pain score of 0.

Bone transport using circular external fixation can serve as a rational and effective final limb salvage strategy for infected tibial pilon fracture nonunion with large bone defects, particularly after repeated failure of microsurgical reconstruction.