Intramedullary screw fixation of proximal fifth metatarsal fractures: a biomechanical study.

Shah, S N; Knoblich, G O; Lindsey, D P; Kreshak, J; Yerby, S A; Chou, L B · Foot Ankle Int · 2001

biomechanical · Level V

Where this comes from

Abstract

Intramedullary screw fixation is a popular technique for treatment of proximal fifth metatarsal fractures. The purpose of this study was to compare the fixation rigidity of a 5.5 mm partially threaded cannulated titanium screw, with presumed superior endosteal purchase, to a similar 4.5 mm screw. Acute fifth metatarsal fractures were simulated in cadavers, stabilized with intramedullary screws, and loaded to failure in three-point bending. The initial failure loads for the metatarsals fixed with 4.5 mm and 5.5 mm screws were not significantly different (332.4 N vs. 335.2 N, respectively), nor were the ultimate failure loads (849.8 N vs. 702.2 N, respectively). Based upon our results, maximizing screw diameter does not appear to be critical for fixation rigidity and may increase the risk of intraoperative or postoperative fracture.

Medical subject headings

Anatomy