Fifth Metatarsal Tuberosity Fracture Fixation: A Biomechanical Study

Abstract

This study tested the hypothesis that fixation of a fifth metatarsal tuberosity fracture with a lag screw that engages the intact medial cortex is biomechanically stronger than fixation with a long intramedullary screw (control). The right and left feet from 10 male cadavers were alternately assigned to the two fixation groups. After fracture reduction and fixation, each specimen was potted in acrylic cement and tested on a servohydraulic testing machine. The repairs were then distracted until failure by placing the peroneus brevis tendon under tension at a rate of 1 mm/s. The lag screw technique resulted in a significantly greater mean (± SD) load to failure (150 ± 90 N) than did intramedullary screw fixation (70 ± 60 N) ( p < .05) and may offer a useful method of internal fixation of fifth metatarsal tuberosity fractures when surgical stabilization is indicated.