Knee prosthesis

A knee joint prosthesis for implantation in a knee of a patient, the knee joint defining a junction of a femur of the patient and a tibia of the patient;

• the knee joint prosthesis comprising:
• a tibial baseplate configured to be implanted on the tibia, the tibial baseplate comprising an insert interface;
• a femoral component configured to be implanted on the femur, wherein the femoral component comprises a medial condyle with a medial articulation surface and a lateral condyle with a lateral articulation surface, wherein the medial articulation surface and the lateral articulation surface are shaped substantially symmetrically to each other across a femoral component plane bisecting the femoral component;
• and
• a tibial insert comprising a baseplate interface attachable to the insert interface of the tibial baseplate;
• wherein the tibial insert comprises an articulation surface with a medial articulation side configured to articulate with the medial articulation surface and a lateral articulation side configured to articulate with the lateral articulation surface, wherein the medial articulation side and the lateral articulation side are shaped substantially asymmetrically to each other across a tibial insert plane bisecting the tibial insert,
• wherein:
• the medial articulation side comprises a medial side height differential defined by:
• a posterior side with a first height, and
• an anterior side with a second height;
• the lateral articulation side comprises a lateral side height differential defined by:
• a posterior side with a third height, and
• an anterior side with a fourth height;
• and wherein
• the medial side height differential is greater than the lateral side height differential;
• wherein the medial articulation side comprises an anterior section with a maximum anterior height and a posterior section with a maximum posterior height;
• the posterior section further comprising a posterior ramp;
• the posterior ramp having a first height proximate a medial posterior section of the medial articulation side and a second height anterior and/or distal to the medial posterior section, wherein the first height is greater than the second height;
• wherein the lateral articulation side comprises an anterior section with a maximum anterior height and a posterior section with a maximum posterior height;
• wherein the maximum posterior height of the medial articulation side is greater than the maximum posterior height of the lateral articulation side;
• wherein the femoral component and the tibial insert are shaped such that, after implantation in the knee, the femoral component and the tibial insert engage at a medial dwell point and a lateral dwell point, wherein the medial dwell point migrates medially and/or the lateral dwell point migrates laterally during flexion of the knee, creating a tibiofemoral rotation between extension and flexion while the knee joint is stabilized by maintenance of tension in at least a medial collateral ligament of the knee.