title: A three-dimensional computed tomography study of distal femoral morphology in Japanese patients: gender differences and component fit.
abstract: BACKGROUND
  Previous anthropometric studies have reported gender differences in distal femoral morphology. However, to date, very few studies have investigated the knee morphology of Japanese adults and possible gender differences. The purpose of this study was to examine the distal femoral morphology of Japanese patients, to characterize anatomical differences between male and female, and to evaluate the need to create gender-specific knee prostheses.
  
  
  METHODS
  We evaluated 80 knees in 40 male and 40 female Japanese patients scheduled for total knee arthroplasty (TKA). The mediolateral (ML) and anteroposterior (AP) dimensions of the knees at different levels were measured preoperatively using three-dimensional computed tomography, and ML/AP aspect ratios were calculated.
  
  
  RESULTS
  On the distal femoral cut surface, the mean ML widths were 74.9 mm for male and 65.1mm for female, and the mean AP lengths were 63.4mm for male and 58.9 mm for female. Such values were generally smaller compared to data from European and North American studies. In this study, the mean ML/AP aspect ratios were 1.31 for male and 1.25 for female, higher than those from non-Asian regions. The ML/AP ratios of Japanese patients were negatively correlated with distal femoral AP length.
  
  
  CONCLUSIONS
  Japanese female had a relatively narrower femoral width for a given AP length than male. Our study suggests the utility of Japanese-specific implants and provides useful insights for manufacturers to design components of appropriate sizes and aspect ratios for Japanese TKA patients.
authors.affiliation: Department of Bone and Joint Surgery, Graduate School of Medicine, Ehime University, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Ishimaru
authors.affiliation: Department of Bone and Joint Surgery, Graduate School of Medicine, Ehime University, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Hino
authors.affiliation: Department of Bone and Joint Surgery, Graduate School of Medicine, Ehime University, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Onishi
authors.affiliation: Department of Bone and Joint Surgery, Graduate School of Medicine, Ehime University, Japan.
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Iseki
authors.affiliation: Department of Bone and Joint Surgery, Graduate School of Medicine, Ehime University, Japan.
authors.forename: Naohiko
authors.initials: N
authors.lastname: Mashima
authors.affiliation: Department of Bone and Joint Surgery, Graduate School of Medicine, Ehime University, Japan. Electronic address: miura@m.ehime-u.ac.jp.
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Miura
mesh_terms: D000368:Aged; D000886:Anthropometry; D044466:Asian People; D005260:Female; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007564:Japan / Q000208:ethnology; D007720:Knee Prosthesis; D008297:Male; D012189:Retrospective Studies; D012727:Sex Characteristics; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Distal femoral morphology; Femoral component; Gender difference; Japanese patient; Total knee arthroplasty