Articulated prosthetic knee and method for implanting same

A method for implanting an articulated knee as a replacement of the natural knee of a patient comprising the steps of providing a femoral implant including a condyle section and an elongated femoral stem protruding from the section;

• providing a tibial implant including a tibial plateau section and an elongated tibial stem protruding from the plateau section;
• implanting the femoral implant in the patient's femur by positioning the femoral stem in the patient's femoral canal and in substantial alignment therewith;
• implanting the tibial implant in the patient's tibia by positioning the tibial stem in the patient's tibial canal and in substantial alignment therewith and cementing the respective implants to the femur and the tibia by applying a bonding agent therebetween;
• providing a resilient plate member;
• positioning the plate member between opposing surfaces of the sections so that the plate member is compressed when a force is applied to the implant which tends to move the implants beyond their fully extended position;
• embedding a portion of the plate member in the bonding agent so that the plate member is directly secured to and structurally integrated with the patient's tibia;
• pivotally interconnecting the implants about a pivot axis for pivotal motion of the implants and therewith of the patient's tibia relative to the patient's femur between an extended position in which the tibia and the femur are in substantial alignment and a flexed position in which they are obliquely inclined;
• and positioning the pivot axis about which the implants pivot so that the patient's tibia is positioned anterior of its normal, anatomical position.

An articulated knee prosthesis comprising a femoral implant including a condyle section and an elongated femoral stem protruding from the section for implantation in the femoral canal of a patient;

• a tibial implant including a tibial plateau section and an elongated tibial stem protruding from the plateau section for implantation in the tibial canal of a patient;
• the implants defining an anterior implant portion and a posterior implant portion;
• a plate member having upper and lower surfaces shaped to correspond to opposing surfaces defined by the implant sections for engaging such surfaces and thereby limiting relative movement between the implants beyond the extended position;
• said plate member includes a post extending therefrom and through an aperture in said plateau section so that a free end of the post protrudes from an underside of the plateau section facing the patient's tibia;
• whereby upon the implantation of the tibial implant and its attachment to the patient's tibia with cement, the cement also bonds to the post and thereby structurally integrates the post with the plateau section, the cement and the patient's tibia;
• hinge means interconnecting the implants, positioned proximate the posterior portions of the implants and permitting relative pivotal motion of the implants about a pivot axis defined by the hinge means between an extended position in which the stems are in substantial alignment and a flexed position in which the stems are obliquely inclined relative to each other.