Summary
Objective: To report on a novel surgical procedure to treat a long segmental tibial defect in
a five-year-old 5 kg spayed female Main Coon cat using transverse distraction osteogenesis
in the contralateral tibia to create a free autograft.
Methods: A long free bone segment was created from the cranial half of the normal tibia. A
circular external fixator was constructed to give the segment 7 mm of cranial distraction.
After 42 days the widened section of tibial bone was removed and transferred to the
defect in the contralateral tibia. Locking plates were used to stabilize the graft
and to protect the donor tibial sites.
Results: By 27 months, both tibias were healed, all implants had been removed, function was
excellent, and the overall limb length was 90% of the normal side.
Clinical relevance: Compared with longitudinal distraction osteogenesis in long bone defects, transverse
distraction of a normal bone requires a significantly shorter distraction distance
to produce a similar amount of bone. Thus, distraction time is reduced, with less
likelihood of significant soft tissue damage. New bone may be more reliably regenerated
in a normal limb due to better tissue health, and native bone may be more readily
incorporated than allografts in compromised sites. Disadvantages include the increased
morbidity, as well as the risk and expense associated with involvement of a normal
limb.
Keywords
Distraction osteogenesis - free cortical autograft - bone defects - circular external
fixator - bone-widening
