Dynamic in-vivo tibio-femoral and bearing motions in mobile bearing knee arthroplasty.
To determine the tibio-femoral and bearing motions in well functioning mobile bearing total knee arthroplasties, a quantitative analysis by means of fluoroscopy was carried out during stair ascending, chair rising-sitting and step up-down motor tasks. Femoral and tibial component positions were obtained using a CAD-model-based shape matching technique. Direct measurement of mobile bearing motion was carried out by tracking previously inserted tantalum beads. A relatively small motion of the bearing was observed. The advantage of self-alignment claimed for the mobile bearing arthroplasty seems to be confirmed by subject-specific ranges of motion exhibited by these patients. It has also been demonstrated that these total knee arthroplasties, which are not fully conforming in flexion, provide little constraint to antero-posterior motion, leading to a kinematic pattern very similar to an ACL deficient knee.
Fantozzi
S
S
Movement Analysis Laboratory, Istituti Ortopedici Rizzoli, Via di Barbiano 1/10, 40136, Bologna, Italy. fantozzi@ior.it
Leardini
A
A
Banks
S A
SA
Marcacci
M
M
Giannini
S
S
Catani
F
F
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur / Q000502:physiology*; D005471:Fluoroscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D007720:Knee Prosthesis; D008297:Male; D011474:Prosthesis Design; D012399:Rotation; D013647:Task Performance and Analysis; D013977:Tibia / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology*