Overlapping bone transport as a bone-preserving docking strategy for a massive wedge-shaped infected tibial defect: a...

Large infected tibial defects remain amongst the most challenging problems in limb reconstruction, particularly when the defect is wedge-shaped rather than purely segmental. In such cases, conventional docking may require resection of irregular but viable cortex to create a flat surface, resulting in additional iatrogenic bone loss. We report a selected bone-preserving reconstruction in which the native geometry of a wedge-shaped defect was intentionally utilised during bone transport.

A 20-year-old man was referred after polytrauma and multiple failed surgeries. He presented with methicillin-resistant Staphylococcus aureus infection, a 90-mm wedge-shaped tibial defect, severe equinus deformity, and a draining soft-tissue defect. After irrigation and debridement, vancomycin-loaded cement beads were placed and intravenous daptomycin was administered. Bone transport was initiated after cultures became negative and inflammatory markers normalised. Pre-transport radiographs and computed tomography, including three-dimensional reconstructions, demonstrated a preserved posterior cortical remnant and a defect morphology compatible with overlap engagement. During debridement, the retained posterior cortex showed punctate cortical bleeding (paprika sign) and no gross sequestration. During the late transport phase, the distal posterior cortex overlapped with the proximal segment, creating a partial bone-in-bone engagement. The overlap length increased from approximately 8 mm before transport to 63 mm after docking, corresponding to 55 mm of additional cortical engagement; the estimated cortical overlap contact area was approximately 2,079 mm². Bone chipping and alignment correction were subsequently performed. Equinus deformity was corrected gradually using a Taylor Spatial Frame after Achilles tendon lengthening. At 14-year follow-up, union was maintained without recurrence of infection. The patient had mild pain (VAS 10/100), independent ambulation without orthosis, excellent ASAMI bone results, and good functional results.

This case illustrates a bone-preserving docking strategy within an established bone transport framework. In selected wedge-shaped defects, viable residual cortex should not be routinely resected solely for geometric simplification if it can be safely incorporated into docking after infection control and careful assessment of biological viability.