Variability in femoral component rotation reference axes measured during navigation-assisted total knee arthroplasty using gap technique.
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.
Moon
Young-Wan
YW
Department of Orthopedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Seo
Jai-Gon
JG
Lim
Seung-Jae
SJ
Yang
Jae-Hyuk
JH
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