Strength analysis of intraosseous wire fixation for avulsion fractures of the fifth metatarsal base.

The objective of this study was to gather pilot data of the pullout strength of intraosseous wire for fixation of fifth metatarsal avulsion fractures and to compare intraosseous wire fixation with tension-band wiring. Osteotomies consistent with fifth metatarsal avulsion fractures were created in 5 matched pairs of cadaver limbs. One limb of each pair underwent fixation with intraosseous wiring and the other with tension band wiring. Metatarsals were then loaded to failure, defined as the maximum force achieved before the slope of the load curve moved from a positive to a negative value. Tension-band wiring showed a mean strength of 164.5 +/- 103.7 N compared with a mean strength of 113.7 +/- 46.6 N for intraosseous wiring. No significant difference in strength was shown between methods of fixation. Although the power of this data is small (.143), the data indicate that intraosseous wiring shows similar pullout strength when compared with tension-band wiring for fixation of fifth metatarsal avulsion fractures.