Fatigue failure in small diameter tibial nails.

The prevalence of implant failure in small diameter tibial nails has not been well characterized. In a series of 130 tibial fractures stabilized with 8-mm and 9-mm nails, implant failure occurred in 18 fractures (13.8%): 4 nails (3%) broke and 16 (12.3%) screws failed. All nail failures occurred in open, unstable fractures with delayed union, and all of the nails that broke were dynamically locked during the failure. Of the 130 fractures, 128 (98.5%) eventually united. Delayed union, degree of comminution, metaphyseal location, and dynamic locking of unstable fractures contribute to hardware failure. Based on these findings, dynamization could be used to treat delayed union only in axially stable diaphyseal fractures. Exchange nailing is recommended to treat delayed union in comminuted or metaphyseal fractures to prevent hardware failure. Bone grafting should be performed at 6 to 12 weeks for fractures with > 50% bone loss.