title: Intramedullary screw fixation of proximal fifth metatarsal fractures: a biomechanical study.
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.
authors.affiliation: Department of Functional Restoration, Stanford University School of Medicine, CA 94305, USA.
authors.forename: S N
authors.initials: SN
authors.lastname: Shah
authors.forename: G O
authors.initials: GO
authors.lastname: Knoblich
authors.forename: D P
authors.initials: DP
authors.lastname: Lindsey
authors.forename: J
authors.initials: J
authors.lastname: Kreshak
authors.forename: S A
authors.initials: SA
authors.lastname: Yerby
authors.forename: L B
authors.initials: LB
authors.lastname: Chou
mesh_terms: D001696:Biomechanical Phenomena; D001863:Bone Screws; D002102:Cadaver; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008682:Metatarsal Bones / Q000293:injuries* / Q000601:surgery*