Illustrative implant motion · contact is checked at each sampled flexion angle. This is not a prediction of ligament balance or clinical motion.
The ACL and PCL retain their bone attachments as the knee bends. The medial side travels less than the lateral side.
Tibia held still for comparison. A posterior shift of the femur represents anterior tibial translation relative to the femur.
Illustrative motion—not a prediction of instability, ligament strain, or contact pressure.
Model and component details
Femoral component: supplied Persona CR CAD, size 11 Right. Tibial tray: supplied Persona cemented keel CAD, size E Right. Bearing: the accepted MC-inspired illustration from Part 5, not manufacturer bearing CAD. Assembly is for visual review; motion is an authored geometric illustration, with both compartments seated at sampled angles.
The intact trajectory reuses our previously refined 0–120° animation: limited early medial travel, greater lateral rollback, and coupled rotation. Its timing and excursions are authored teaching values.
The torn-ACL example adds a smooth illustrative offset strongest near extension (up to 3 mm relative translation and 2° rotation). These are not patient-specific measurements or a load/force simulation. Different tasks and loading produce different ACL-deficient motion.
Li et al. · ACL-deficient knee kinematics
ACL-deficient knee during squatting
ACL and PCL surfaces are reused from the earlier Open Knee(s) model and fitted to the approved bones. Attachments and fiber deformation need anatomical review; deformation is not calculated from ligament forces. The ACL discontinuity is schematic. Menisci are illustrative crescent wedges fitted to the approved tibial surfaces, with posterior body movement and retained horn locations. The solid wedge and smoothed tibial fit are illustrative; this is not a contact-pressure or tissue-deformation simulation. The patella is omitted. Vedi et al. · Dynamic MRI of meniscal movement.
Open Knee(s) attribution