title: The linea aspera as a guide for femoral rotation after tumor resection: is it directly posterior? A technical note.
abstract: BACKGROUND
  The linea aspera is the rough, longitudinal crest on the posterior surface of the femoral shaft. Most orthopedic surgeons depend on the linea aspera as an intraoperative landmark identifying the true posterior aspect of the femur. We investigated the position of the linea aspera to verify whether the surgeon can rely on this accepted belief.
  
  
  METHODS
  One hundred and thirty-three femora from 73 patients were evaluated. Four CT cuts were done of the mid femur, and we measured the angle of rotation of the linea aspera at each cut.
  
  
  RESULTS
  The linea aspera was externally rotated in most femora evaluated; average angles of rotation were 15.4°, 14°, 11.7°, and 11.5° at 10, 15, 20, and 25 cm from the intercondylar line, respectively. The angle of rotation of the linea aspera was positively correlated with femoral neck anteversion angle and negatively with age.
  
  
  CONCLUSIONS
  The linea aspera is exactly posterior in a minority of individuals, while it is externally rotated to varying degrees in the majority of individuals. The degree of rotation was positively correlated with femoral neck anteversion angle, and negatively with age. To avoid implant malrotation, accurate estimation of the rotation angle should be determined preoperatively.
  
  
  METHODS
  Level IV.
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, 921-8641, Japan. ahmedallam200@hotmail.com.|Department of Orthopedic Surgery, Faculty of Medicine, Sohag University, Nasser city, 82524, Sohag, Egypt. ahmedallam200@hotmail.com.
authors.forename: Ahmed Hamed Kassem
authors.initials: AH
authors.lastname: Abdelaal
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, 921-8641, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Yamamoto
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, 921-8641, Japan.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Hayashi
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, 921-8641, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Takeuchi
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, 921-8641, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Miwa
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, 921-8641, Japan.|Department of Orthopedic Surgery, Faculty of Medicine, Sohag University, Nasser city, 82524, Sohag, Egypt.
authors.forename: Ahmad Fawaz
authors.initials: AF
authors.lastname: Morsy
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, 921-8641, Japan.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Kajino
authors.affiliation: Department of Orthopedic Surgery, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa, 921-8641, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuchiya
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D059925:Anatomic Landmarks; D019644:Arthroplasty, Replacement, Hip; D002648:Child; D005260:Female; D005266:Femoral Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D012399:Rotation; D014057:Tomography, X-Ray Computed
keywords: Intraoperative guide for posterior; Linea aspera; Tumor resection