title: Accurate determination of screw position in treating fifth metatarsal base fractures to shorten radiation exposure time.
abstract: BACKGROUND
  Anatomical markers can help to guide lag screw placement during surgery for internal fixation of fifth metatarsal base fractures. This study aimed to identify the optimal anatomical markers and thus reduce radiation exposure.
  
  
  METHODS
  A total of 50 patients in Huashan Hospital, Shanghai, China, who underwent oblique foot radiography in the lateral position were randomly selected. The angles between the fifth metatarsal axis and cuboid articular surface were measured to determine the optimal lag screw placement relative to anatomical markers.
  
  
  RESULTS
  The line connecting the styloid process of the fifth metatarsal base with the second metatarsophalangeal (MTP) joint intersected with the fifth metatarsal base fracture line at an angle of 86.85° ± 5.44°. The line connecting the fifth metatarsal base styloid with the third and fourth MTP joints intersected with the fracture line at angles of 93.28° ± 5.24° and 100.95° ± 5.00°, respectively. The proximal articular surface of the fifth metatarsal base intersected with the line connecting the styloid process of the fifth metatarsal base with the second, third and fourth MTP joints at angles of 24.02° ± 4.77°, 30.79° ± 4.53° and 38.08° ± 4.54°, respectively.
  
  
  CONCLUSIONS
  The fifth metatarsal base styloid and third MTP joint can be used as anatomical markers for lag screw placement in fractures involving the fifth tarsometatarsal joint. The connection line, which is normally perpendicular to the fracture line, provides sufficient mechanical stability to facilitate accurate screw placement. The use of these anatomical markers could help to reduce unnecessary radiation exposure for patients and medical staff.
authors.affiliation: Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Jia Zhang
authors.initials: JZ
authors.lastname: Huang
authors.affiliation: Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Ma
mesh_terms: D001863:Bone Screws; D002681:China; D005528:Foot; D005593:Fracture Fixation, Internal; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008682:Metatarsal Bones / Q000528:radiation effects* / Q000601:surgery*; D056888:Patient Positioning; D000069079:Radiation Exposure; D011859:Radiography; D013314:Stress, Mechanical
keywords: fifth metatarsal fracture; internal fixation; radiation