title: Dorsal intercalated segmental instability associated with malunion of a reconstructed scaphoid.
abstract: We analysed scaphoid deformity as a result of surgical treatment of scaphoid fracture nonunion and assessed the deformity associated with a dorsal intercalated segmental instability pattern of carpal malalignment. A total of 45 patients who were treated for scaphoid fracture nonunion were included in the study. The height-to-length ratio of the scaphoid was measured on computed tomographic images and used to assess scaphoid deformity. Carpal malalignment was quantified based on the radio-lunate angle. A correlation analysis between the height-to-length ratio and the radio-lunate angle was performed. Dorsal intercalated segmental instability was defined as a radio-lunate angle >15°, and a receiver operating curve analysis was used to calculate the cutoff height-to-length ratio that can be accompanied with dorsal intercalated segmental instability. Extension of the lunate increases in proportion to the flexion deformity of the scaphoid; dorsal intercalated segmental instability can occur if the height-to-length ratio of the scaphoid is >0.73.
  
  
  METHODS
  IV.
authors.affiliation: 1 Department of Orthopaedic Surgery, Seonam University College of Medicine, Goyang, Korea.
authors.forename: J-H
authors.initials: JH
authors.lastname: Kim
authors.affiliation: 2 Department of Orthopaedic Surgery, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: K-H
authors.initials: KH
authors.lastname: Lee
authors.affiliation: 2 Department of Orthopaedic Surgery, Hanyang University College of Medicine, Seoul, Korea.
authors.forename: B G
authors.initials: BG
authors.lastname: Lee
authors.affiliation: 3 Department of Orthopaedic Surgery, Eulji University College of Medicine, Seoul, Korea.
authors.forename: C-H
authors.initials: CH
authors.lastname: Lee
authors.affiliation: 4 Department of Orthopaedic Surgery, Hanil General Hospital, Seoul, Korea.
authors.forename: S-J
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: 5 Department of Orthopaedic Surgery, Ajou University School of Medicine, Suwon, Korea.
authors.forename: W-S
authors.initials: WS
authors.lastname: Choi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D050824:Carpal Joints; D015331:Cohort Studies; D005260:Female; D005599:Fractures, Ununited / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007593:Joint Instability / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D021361:Scaphoid Bone / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Scaphoid malunion; carpal malalignment; dorsal intercalated segmental instability