title: Distal femur rotation relates to joint obliquity in ACL-deficient Chinese.
abstract: BACKGROUND
  The lower limb osteometry of Chinese differs from that of whites. The joint line of the knee in the coronal plane in Chinese is more medially inclined and the posterior condylar angle of the distal femur in the axial plane is larger. However, it is unclear whether there is any direct association between the coronal plane and axial plane osteometry.
  
  
  OBJECTIVE
  We asked whether the joint line obliquity of the knee is related to the posterior condylar angle of the distal femur in young Chinese subjects.
  
  
  METHODS
  Ninety-nine young Chinese patients with anterior cruciate ligament injuries were recruited. The lower limb alignment and joint line obliquity were measured using standing long radiographs of the whole lower limb. The rotational alignment of the distal femur was assessed in the axial cuts of the MRI.
  
  
  RESULTS
  The distal femur rotational alignment was associated with the obliquity of the knee in Chinese. The posterior condylar angle was 5° ± 2°. The knee was 5° ± 3° medially inclined.
  
  
  CONCLUSIONS
  The joint line of the knee in a group of young Chinese patients was more medially inclined than that of whites. The posterior condylar angle of the distal femur was larger. The presence of an association between distal femur rotational alignment and joint line obliquity in this group of young Chinese patients suggests a possible developmental cause explaining the difference in osteometry between races.
authors.affiliation: Department of Orthopaedics and Traumatology, The University of Hong Kong, Queen Mary Hospital, Pokfulam Road, Hong Kong, Hong Kong. peterwpy@hkucc.hku.hk
authors.forename: W P
authors.initials: WP
authors.lastname: Yau
authors.forename: K Y
authors.initials: KY
authors.lastname: Chiu
authors.forename: August W M
authors.initials: AW
authors.lastname: Fok
authors.forename: C H
authors.initials: CH
authors.lastname: Yan
authors.forename: F Y
authors.initials: FY
authors.lastname: Ng
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000070598:Anterior Cruciate Ligament Injuries; D044466:Asian People; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D007718:Knee Injuries / Q000000981:diagnostic imaging / Q000208:ethnology / Q000503:physiopathology*; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D011859:Radiography; D016059:Range of Motion, Articular; D055815:Young Adult