title: Femoral component rotation in patients with leg axis deviation.
abstract: OBJECTIVE
  Correct alignment of the rotation of the femoral component and the flexion gap after total knee arthroplasty is difficult in patients with preoperative leg axis deviation. Inaccuracy may result in problems with the patellofemoral joint and instability, in particular. We examined the influence of the preoperative leg axis on the rotation of the femoral component and the symmetry of the flexion gap after total knee arthroplasty using the tibial-cut-first technique.
  
  
  METHODS
  A retrospective study was carried out of 58 consecutive patients who underwent primary LCS total knee arthroplasty using the tibial-cut-first technique in 2008 based on preoperative full-leg radiographs and the final radiographs taken according to Kanekasu's technique. The patients were divided into three groups (varus-valgus-neutral) according to their preoperative leg axis.
  
  
  RESULTS
  Using the tibial-cut-first technique, a mean neutral rotation of the femoral component of 0.5° and a mean symmetrical flexion gap of -0.7° were achieved. Nevertheless, there was a positive correlation of the preoperative leg axis with the rotation of the femoral component. The differences in the rotation of the femoral component and the flexion gap between the three groups were not significant. The only significant difference between the varus and valgus groups was the extent of rotation of the femoral component, with a slightly greater external rotation of 2.7° in the valgus group.
  
  
  CONCLUSIONS
  This study suggests that it is possible to achieve correct rotational alignment of the femoral component and a symmetrical flexion gap using the tibial-cut-first technique in patients with a preoperatively deviated leg axis.
authors.affiliation: Department of Orthopaedic Surgery, University of Duisburg-Essen, Pattbergstrasse 1-3, 45239 Essen, Germany. timclassen@gmx.de
authors.forename: Tim
authors.initials: T
authors.lastname: Classen
authors.forename: Stefan
authors.initials: S
authors.lastname: Landgraeber
authors.forename: Alexander
authors.initials: A
authors.lastname: Wegner
authors.forename: Ralf-Dietrich
authors.initials: RD
authors.lastname: Müller
authors.forename: Marius
authors.initials: M
authors.lastname: von Knoch
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D005269:Femur / Q000033:anatomy & histology*; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012399:Rotation