Total knee arthroplasty kinematics. An in vivo evaluation of four different designs.
Thirty-four patients who had 42 total knee arthroplasties during the past 5 years were examined. Four types of total knee arthroplasties (Tricon-M, PCA, Variable Axis, and Anametric) were evaluated, using a computerized knee evaluation system. The patients and 10 controls with normal knees were tested for anteroposterior stability with the Lachman test, medial/lateral stability at 20 degrees, varus/valgus stability at 20 degrees, internal/external rotation at 80 degrees and 20 degrees of flexion, and internal/lateral rotation (screw home) over the active range of motion. At 30 degrees of flexion, the Variable Axis prosthesis was 54% more constrained than the normal knee to anterior/posterior shear. The Anametric and the Variable Axis were more lax under varus/valgus stress than the normal knee by 85% and 71%, respectively. There were no statistical differences for any of the other tests.
Stein
A
A
McClure Musculoskeletal Research Center, University of Vermont, Burlington 05405.
Fleming
B
B
Pope
M H
MH
Howe
J G
JG
D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis; D007719:Knee Joint / Q000502:physiology; D007720:Knee Prosthesis; D008297:Male; D009068:Movement; D011474:Prosthesis Design