title: Multiplanar CT Analysis of Fifth Metatarsal Morphology: Implications for Operative Management of Zone II Fractures.
abstract: BACKGROUND
  Percutaneous internal fixation is currently the method of choice treating proximal zone II fifth metatarsal fractures. Complications have been reported due to poor screw placement and inadequate screw sizing. The purpose of this study was to define the morphology of the fifth metatarsal to help guide surgeons in selecting the appropriate screw size preoperatively.
  
  
  METHODS
  Multiplanar analysis of fifth metatarsal morphology was completed using computed tomographic (CT) scans from 241 patients. Specific parameters were analyzed and defined in anteroposterior (AP), lateral, and oblique views including metatarsal length, distance from the base to apex of curvature, apex medullary canal width, apex height, and fifth metatarsal angle.
  
  
  RESULTS
  The average metatarsal length in the AP view was 71.4 ± 6.1 mm and in the lateral view 70.4 ± 6.0 mm, with 95% of patients having lengths between 59.3 and 83.5 mm and 58.4 and 82.4 mm, respectively. The average canal width at the apex of curvature was 4.1 ± 0.9 mm in the AP view and 5.3 ± 1.1 mm in the lateral view, with 95% of patients having widths between 2.2 and 5.9 mm and 3.2 and 7.5 mm, respectively. Average distance from apex to base was 42.6 ± 5.8 mm in the AP and 40.4 ± 6.4 mm in the lateral views. Every measurement taken in all 3 views had a significant correlation with height.
  
  
  CONCLUSIONS
  When determining screw length, we believe lateral radiographs should be used since the distance from the base of the metatarsal to the apex was smaller in the lateral view. On average, the screw should be 40 mm or less to reduce risk of distraction. For screw diameter, the AP view should be used because canal shape is elliptical, and width was found to be significantly smaller in the AP view. Most canals can accommodate a 4.0- or 4.5-mm-diameter screw, and one should use the largest diameter screw possible. Larger individuals were likely to have more bowing in their metatarsal shaft, which may lead to a higher tendency to distract.
  
  
  METHODS
  Level III, comparative series.
authors.affiliation: Hospital for Special Surgery, New York, NY, USA desandisb@hss.edu.
authors.forename: Bridget
authors.initials: B
authors.lastname: DeSandis
authors.affiliation: Department of Orthopedic Surgery, UPMC, Pittsburgh, PA, USA.
authors.forename: Conor
authors.initials: C
authors.lastname: Murphy
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Rosenbaum
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Levitsky
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Quinn
authors.initials: Q
authors.lastname: O'Malley
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Konin
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Drakos
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D005260:Female; D018409:Foot Injuries / Q000601:surgery; D005593:Fracture Fixation, Internal / Q000379:methods*; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D008682:Metatarsal Bones / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery; D008875:Middle Aged; D011859:Radiography; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Jones fracture; anatomy; intramedullary screw fixation; morphology; proximal fifth metatarsal fracture; radiographic study