| 摘要 |
The invention concerns a total knee prosthesis, comprising a femoral implant (1), a tibial plateau (3), mounted on a tibial base plate (2) rotating about a vertical axis (YY), the femoral implant comprising two lateral condyles (5) shaped for co-operating with corresponding concave support surfaces (7) of the tibial plateau, to enable flexion-extension movements and internal-external rotation about the vertical axis; the tibial plateau support surfaces (7) and the condyle surfaces (5a) are congruent up to a flexion of about 90 degrees; stop means are provided on the plateau (12) and the condyles (14) to bring about, at the end of the flexion beyond 90 degrees, a roll back in the antero-posterior plane of the condyles and their support zones (11) on the tibial plateau, to ensure posterior stabilisation of the femoral implant; the femoral implant (1) roll back at the end of the flexion enables to optimise the functioning of the extensor apparatus reducing the muscular strength required from the patient for rising from a sitting position or for climbing stairs, making up for the absence of the posterior cruciate ligament. |
