title: Screw placement in percutaneous acetabular surgery: gender differences of anatomical landmarks in a cadaveric study.
abstract: OBJECTIVE
  Percutaneous reduction and periarticular screw implantation techniques have been successfully introduced in acetabular surgery. The advantages of this less invasive approach are attenuated by higher risks of screw misplacement. Anatomical landmarks are strongly needed to prevent malplacement. This cadaver study was designed to identify reliable anatomical osseous landmarks in the pelvic region for screw placement in acetabular surgery. Gender differences were specifically addressed.
  
  
  METHODS
  Twenty-seven embalmed cadaveric hemipelvic specimens (13 male, 14 female) were used. After soft-tissue removal, anterior and posterior column acetabular screw placement was conducted by one orthopaedic trauma surgeon under direct vision. Each column was addressed by antegrade and retrograde screw insertion. Radiographic verification of ideal screw placement was followed by assessment of the distance from the different entry points to adjoining anatomical osseous structures.
  
  
  RESULTS
  For anterior column screw positioning, the posterior superior iliac spine (PSIS), posterior inferior iliac spine (PIIS), iliopectineal eminence and centre of the symphysis were most reliable regarding gender differences. For posterior column screw positioning, the distance to the anterior superior iliac spine (ASIS) and the ischial tuberosity showed the lowest deviation between the different gender specimens. Highest gender differences were seen in relation to the cranial rim of the superior pubic ramus in retrograde anterior column screw positioning (p = 0.002). Most landmarks could be targeted within a 2.5-cm range in all specimens.
  
  
  CONCLUSIONS
  The findings emphasise the relevance of osseous landmarks in acetabular surgery. By adhering to easily identifiable structures, screw placement can be safely performed. Significant gender differences must be taken into consideration during preoperative planning.
authors.affiliation: Department of Trauma Surgery, University Hospital Regensburg, Regensburg, Germany. tdienstknecht@ukaachen.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Dienstknecht
authors.forename: Michael
authors.initials: M
authors.lastname: Müller
authors.forename: Richard
authors.initials: R
authors.lastname: Sellei
authors.forename: Michael
authors.initials: M
authors.lastname: Nerlich
authors.forename: Franz Josef
authors.initials: FJ
authors.lastname: Müller
authors.forename: Bernd
authors.initials: B
authors.lastname: Fuechtmeier
authors.forename: Arne
authors.initials: A
authors.lastname: Berner
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery*; D017760:Bone Malalignment / Q000517:prevention & control; D001863:Bone Screws; D002102:Cadaver; D005260:Female; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D019637:Orthopedic Procedures / Q000379:methods*; D010384:Pelvic Bones / Q000000981:diagnostic imaging; D011631:Pubic Symphysis / Q000000981:diagnostic imaging; D011859:Radiography; D012737:Sex Factors