title: Radiographic diagnosis of sagittal plane rotational displacement in pelvic fractures: a cadaveric model and clinical case study.
abstract: OBJECTIVE
  Our objective was to measure the sagittal plane rotational (flexion and extension) displacement of hemipelvis radiologically and analyze the ratio of flexion and extension displacement of unstable pelvic fractures.
  
  
  METHODS
  We used 8 cadaveric models to study the radiographic evidence of pelvic fractures in the sagittal plane. We performed pelvic osteotomy on 8 cadavers to simulate anterior and posterior pelvic ring injury. Radiological data were measured in the flexion and extension group under different angles (5°, 10°, 15°, 20°, and 25°). We retrospectively reviewed 164 patients who were diagnosed with a unilateral fracture of the pelvis. Pelvic ring displacement was identified and recorded radiographically in cadaveric models.
  
  
  RESULTS
  The flexion and extension displacement of pelvic fractures was measured in terms of the vertical distance of fracture from the top of iliac crest to the pubic tubercle (CD) or from the top of iliac crest to the lowest point of ischial tuberosity (AB). Fifty-seven pelves showed flexion displacement and 15 showed extension displacement. Closed reduction including internal fixation and external fixation was successfully used in 141 cases (86.0 %). The success rates of closed reduction in flexion and extension displacement groups were 77 and 73 %, respectively, which were lower than in unstable pelvic ring fractures.
  
  
  CONCLUSIONS
  The sagittal plane rotation (flexion and extension) displacement of pelvic fractures could be measured by special points and lines on the radiographs. Minimally invasive reduction should be based on clearly identified differences between the sagittal plane rotation and the vertical displacement of pelvic fractures.
authors.affiliation: Department of Orthopaedic Surgery, The Second Affiliated Hospital of Wenzhou Medical University, 109 Xue yuan xi Road, Wenzhou, 325000, China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Shui
authors.forename: Xiaozhou
authors.initials: X
authors.lastname: Ying
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Kong
authors.forename: Yongzeng
authors.initials: Y
authors.lastname: Feng
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.forename: Xiaoshan
authors.initials: X
authors.lastname: Guo
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
mesh_terms: D000328:Adult; D002102:Cadaver; D016267:External Fixators; D005260:Female; D005593:Fracture Fixation, Internal; D050723:Fractures, Bone / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D010384:Pelvic Bones / Q000000981:diagnostic imaging* / Q000293:injuries / Q000601:surgery; D011859:Radiography; D012189:Retrospective Studies; D012399:Rotation