title: Variability in femoral component rotation reference axes measured during navigation-assisted total knee arthroplasty using gap technique.
abstract: The basic objective in total knee arthroplasty is to achieve the correct amount of femoral component rotation, and this can be achieved either with a measured resection technique or indirectly with a flexion/extension gap equalization technique. We studied variability in the reference axes (posterior condylar axis, Whiteside's line, transepicondylar axis) when soft tissue tension was managed intraoperatively using a navigation system. The mean angles for the transepicondylar line, Whiteside's line, and the posterior condylar line from the proximal tibia resection plane were 1.29 degrees +/- 3.67 degrees (mean +/- SD; range, -7 degrees to 10.5 degrees), 3.90 degrees +/- 4.17 degrees (mean +/- SD; range, -3 degrees to 15.5 degrees), and -4.03 degrees +/- 2.71 degrees (mean +/- SD; range, -9.5 degrees to 1.0 degrees), respectively. The coefficients of variation (SD/mean x100) for these 3 variables were 283%, 106%, and 67%, respectively. Of the 3 reference axes used widely for femoral component rotation, the angles from the posterior condylar line to the proximal tibia resection plane showed the smallest range of variance.
authors: Department of Orthopedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Young-Wan
authors: YW
authors: Moon
authors: Jai-Gon
authors: JG
authors: Seo
authors: Seung-Jae
authors: SJ
authors: Lim
authors: Jae-Hyuk
authors: JH
authors: Yang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000517:prevention & control; D005260:Female; D005269:Femur / Q000601:surgery*; D006801:Humans; D007719:Knee Joint / Q000502:physiology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013977:Tibia / Q000601:surgery