Tibiofemoral contact areas and pressures in six high flexion knees.
The tibiofemoral articulating interfaces of six high flexion knee designs were examined using a standard testing protocol developed by Harris et al. [J Biomech 32:951-958 (1999)] to investigate the polyethylene insert contact areas and pressures. A load of 3600 N was applied for 10 s at 0, 30, 60, 90, 110, 135 and 155 degrees of flexion. Contact areas and pressures at the femoral-polyethylene insert interface were measured with a I-scan 4000 system. Up to 110 degrees of flexion, the VANGUARD RP HI-FLEX showed the highest contact area and lowest pressure. At the deep flexion angles, contact area decreased and contact pressure increased significantly in all knees. The NexGen series showed a constant contact area throughout the various flexion angles. In general, all high flexion knees could result in almost point contact in an extremely high range of motion.
Shiramizu
Kei
K
Surgical & Orthopaedic Research Laboratories, Prince of Wales Hospital, University of New South Wales, Randwick, NSW, Australia. keishiramizu@gmail.com
Vizesi
Frank
F
Bruce
Warwick
W
Herrmann
Sebastian
S
Walsh
William R
WR
D001696:Biomechanical Phenomena; D019245:Compressive Strength / Q000502:physiology*; D005269:Femur / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008592:Menisci, Tibial / Q000502:physiology; D008962:Models, Theoretical; D016059:Range of Motion, Articular / Q000502:physiology*; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013499:Surface Properties; D013977:Tibia / Q000502:physiology; D016474:Weight-Bearing