Constrained prosthetic knee with rotating bearing

A prosthetic knee, comprising:

• a femoral component having a hinge post rotatably connected thereto;
• a hinge post extension extending from said hinge post;
• a tibial component including a hinge post extension aperture, whereby said hinge post extension is positioned within said hinge post extension aperture when the prosthetic knee is operably assembled, whereby said hinge post is fully constrained by said tibial component against displacement in a direction perpendicular to a longitudinal axis of said hinge post extension, and whereby said femoral component is rotatable about said longitudinal axis of said hinge post extension;
• and
• a meniscal component positioned between said femoral component and said tibial component, said femoral component including a condylar bearing surface, said meniscal component including a cooperative bearing surface abutting said condylar bearing surface of said femoral component;
• wherein said meniscal component includes a hinge post aperture, whereby said hinge post is positioned within said hinge post aperture when the prosthetic knee is operably assembled, said meniscal component being rotatable about a longitudinal axis of said hinge post.

A prosthetic knee, comprising:

• a femoral component having a hinge post rotatably connected thereto;
• a hinge post extension extending from said hinge post;
• a tibial component including a hinge post extension aperture, whereby said hinge post extension is positioned within said hinge post extension aperture when the prosthetic knee is operably assembled, whereby said hinge post is fully constrained by said tibial component against displacement in a direction perpendicular to a longitudinal axis of said hinge post extension, and whereby said femoral component is rotatable about said longitudinal axis of said hinge post extension;
• a meniscal component positioned between said femoral component and said tibial component, said femoral component including a condylar bearing surface, said meniscal component including a cooperative bearing surface abutting said condylar bearing surface of said femoral component;
• and
• a bearing box connected to said femoral component, said bearing box interposed between said hinge post and said femoral component, whereby said hinge post will not contact said femoral component during flexion and extension of the prosthetic knee, said bearing box including a hyperextension stop, said hinge post including a hyperextension stop surface, said hyperextension stop contacting said hyperextension stop surface to prevent further hyperextension of the prosthetic knee beyond a predetermined point of hyperextension.

A prosthetic knee, comprising:

• a femoral component having a hinge post rotatably connected thereto;
• a hinge post extension extending from said hinge post;
• a tibial component including a hinge post extension aperture, whereby said hinge post extension is positioned within said hinge post extension aperture when the prosthetic knee is operably assembled, whereby said hinge post is fully constrained by said tibial component against displacement in a direction perpendicular to a longitudinal axis of said hinge post extension, and whereby said femoral component is rotatable about said longitudinal axis of said hinge post extension;
• and
• a meniscal component positioned between said femoral component and said tibial component, said femoral component including a condylar bearing surface, said meniscal component including a cooperative bearing surface abutting said condylar bearing surface of said femoral component, wherein said hinge post includes an elongate hinge post extension aperture sized for placement of said hinge post extension therein, whereby said hinge post extension traverses a first end of said hinge post extension aperture and protrudes from a second end of said hinge post extension aperture when operably positioned therein, said first and said second ends of said hinge post extension aperture comprising opposing ends of said elongate hinge post extension aperture.

A method of facilitating component choice in a prosthetic knee formed from a femoral component having a hinge post rotatably connected thereto, the hinge post including an elongate hinge post extension aperture sized for placement of a hinge post extension therein, whereby the hinge post extension traverses a first end of the hinge post extension aperture and protrudes from a second end of the hinge post extension aperture when operably positioned therein, the first and the second ends of the hinge post extension aperture comprising opposing ends of the elongate hinge post extension aperture;

• a tibial component including a second hinge post extension aperture, whereby the hinge post extension is positioned within the second hinge post extension aperture when the prosthetic knee is operably assembled;
• and a meniscal component positioned between the femoral component and the tibial component;
• the femoral component including a condylar bearing surface;
• the meniscal component including a cooperative bearing surface facing the condylar bearing surface of the femoral component;
• said method comprising:
• packaging the meniscal component together with the hinge post extension, whereby the hinge post extension is sized relative to the meniscal component so that the hinge post extends about a predetermined distance into the hinge post extension aperture in the tibial component.

A prosthetic knee, comprising:

• a femoral component having a hinge post rotatably connected thereto;
• a hinge post extension extending from said hinge post;
• a tibial component including a hinge post extension aperture, whereby said hinge post extension is positioned within said hinge post extension aperture when the prosthetic knee is operably assembled;
• and
• a bearing box connected to said femoral component, said bearing box interposed between said hinge post and said femoral component, whereby said hinge post will not contact said femoral component during flexion and extension of the prosthetic knee, said bearing box including a hyperextension stop, said hinge post including a hyperextension stop surface, said hyperextension stop contacting said hyperextension stop surface to prevent further hyperextension of the prosthetic knee beyond a predetermined point of hyperextension.

A prosthetic knee comprising:

• a femoral component;
• a tibial component;
• and
• a meniscal component positioned between said femoral component and said tibial component, said femoral component including a condylar bearing surface, said meniscal component including a cooperative bearing surface facing said condylar bearing surface of said femoral component, said condylar bearing surface having a first portion and a second portion, said first portion having a first radius of curvature, said second portion having a second radius of curvature, whereby said femoral component maintains a constant axis of rotation when said first portion contacts said cooperative bearing surface of said meniscal component, whereby said axis of rotation of said femoral component moves away from said meniscal component when said second portion of said femoral component contacts said cooperative bearing surface of said meniscal component, whereby said second portion of said femoral component contacts said meniscal component at three degrees of hyperextension of the prosthetic knee.