Effect of total knee arthroplasty implant position on flexion angle before implant-bone impingement.
We generated patient-specific computer models of total knee arthroplasty from 10 patients to compute maximum flexion angle before implant-bone impingement. Motion was simulated for 5 different femoral implant positions and 11 different tibial insert positions at 4 different tibial posterior slopes. In the neutral position, the mean maximum flexion angle was 136.3°. The range because of anatomical variation among patients was 13.0°. A combination of 2-mm posterior translation of the femoral component with a 10-mm anterior translation of the insert and a 7° posterior slope increased flexion by a mean of 14° relative to the neutral position. The rate of change in flexion angle was 0.4°/mm to 1.5°/mm with respect to implant position and 1.5°/mm increase in the posterior condylar offset.
Mizu-uchi
Hideki
H
Shiley Center for Orthopaedic Research and Education at Scripps Clinic, La Jolla, CA 92037, USA.
Colwell
Clifford W
CW
Matsuda
Shuichi
S
Flores-Hernandez
Cesar
C
Iwamoto
Yukihide
Y
D'Lima
Darryl D
DD
D000368:Aged; D000369:Aged, 80 and over; D019643:Arthroplasty, Replacement / Q000379:methods*; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000517:prevention & control*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000502:physiology* / Q000601:surgery*; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D016119:Posterior Cruciate Ligament / Q000601:surgery; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed