title: Femoral lateral bowing and varus condylar orientation are prevalent and affect axial alignment of TKA in Koreans.
abstract: BACKGROUND
  Coronal alignment is considered key to the function and longevity of a TKA. However, most studies do not consider femoral and tibial anatomical features such as lateral femoral bowing and the effects of these features and subsequent alignment on function after TKA are unclear.
  
  
  OBJECTIVE
  We therefore determined (1) the prevalence of lateral femoral bowing, varus femoral condylar orientation, and severe tibia plateau inclination in female Koreans undergoing TKA; (2) whether postoperative alignments are affected by these anatomical features and improved by the use of navigation; and (3) whether postoperative coronal alignments are associated with function.
  
  
  METHODS
  We measured alignment in 367 knees that underwent TKA and 60 sex- and age-matched normal knees (control group). We determined patterns and degrees of femoral bowing angle, femoral condylar orientation, and tibial plateau inclination on preoperative full-limb radiographs. Postoperatively, coronal alignment of limbs and of femoral and tibial components was measured. We compared American Knee Society scores, WOMAC scores, and SF-36 scores in aligned knees and outliers (beyond ± 3° or ± 2°) at 1 year.
  
  
  RESULTS
  The prevalence of lateral femoral bowing was 88% in the TKA group and 77% in the control group. Mean femoral condylar orientation angle was varus 2.6° in the TKA group and valgus 1.1° in the control group, and mean tibial plateau inclination was varus 8.3° in the TKA group and varus 5.4° in the control group. Femoral lateral bowing and varus femoral condylar orientation were associated with postoperative alignments. Several clinical outcome scales were inferior in the outliers in mechanical tibiofemoral angle, anatomical tibiofemoral angle, and tibial coronal alignment but not in femoral coronal alignment outliers.
  
  
  CONCLUSIONS
  Lateral femoral bowing, varus condylar orientation, and severe varus inclination of the tibia plateau should be considered when performing TKA in Korean patients or patients with otherwise similar anatomical features.
authors.affiliation: Department of Orthopaedics, Cagayan Valley Medical Center, Tuguegarao City, Cagayan, Philippines.
authors.forename: Marco Paolo G
authors.initials: MP
authors.lastname: Lasam
authors.forename: Kil Jae
authors.initials: KJ
authors.lastname: Lee
authors.forename: Chong Bum
authors.initials: CB
authors.lastname: Chang
authors.forename: Yeon Gwi
authors.initials: YG
authors.lastname: Kang
authors.forename: Tae Kyun
authors.initials: TK
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects; D044466:Asian People; D001696:Biomechanical Phenomena; D004185:Disability Evaluation; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007592:Joint Diseases / Q000000981:diagnostic imaging / Q000208:ethnology / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008875:Middle Aged; D015995:Prevalence; D011859:Radiography; D020127:Recovery of Function; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D013977:Tibia / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome