Posterior stabilized orthopaedic prosthesis

An orthopaedic prosthesis comprising:

• a tibial bearing configured to be coupled to a tibial tray, the tibial bearing having a platform and a spine extending upwardly from the platform, the spine having a posterior side including a cam surface having a first section that is convexly curved in the sagittal plane and a second section that is concavely curved in the sagittal plane, and
• a femoral component configured to articulate with the tibial bearing, the femoral component including (i) a pair of spaced apart condyles defining an intracondylar notch therebetween and (ii) a posterior cam positioned at a posterior end of the intracondylar notch, the posterior cam including a cam surface having an anterior section that is concavely curved in the sagittal plane and a posterior section that is convexly curved in the sagittal plane,
• wherein (i) during a first range of flexion, the posterior cam is spaced apart from the spine, (ii) during a second range of flexion greater than the first range of flexion, the anterior section of the cam surface of the posterior cam contacts the first section of the cam surface of the spine and posterior section of the cam surface of the posterior cam is spaced apart from the spine, (iii) during a third range of flexion greater than the second range of flexion, the anterior section of the cam surface of the posterior cam contacts the first section of the cam surface of the spine and posterior section of the cam surface of the posterior cam contacts the second section of the cam surface of the spine, and (iv) during a fourth range of flexion greater than the third range of flexion, the anterior section of the cam surface of the posterior cam is spaced apart from the spine and the posterior section of the cam surface of the posterior cam contacts the second section of the cam surface of the spine.

An orthopaedic prosthesis comprising:

• a tibial bearing configured to be coupled to a tibial tray, the tibial bearing having a platform and a spine extending upwardly from the platform, the spine having a posterior side including a cam surface having a first section that is convexly curved in the sagittal plane and a second section that is concavely curved in the sagittal plane, and
• a femoral component configured to articulate with the tibial bearing, the femoral component including (i) a pair of spaced apart condyles defining an intracondylar notch therebetween and (ii) a posterior cam positioned at a posterior end of the intracondylar notch, the posterior cam including a cam surface having an anterior section that is concavely curved in the sagittal plane and a posterior section that is convexly curved in the sagittal plane,
• wherein (i) at a flexion angle of about 0 degrees of flexion, the posterior cam is disengaged from the spine, (ii) the anterior section of the cam surface of the posterior cam contacts the first section of the cam surface of the spine during a first range of flexion starting at a flexion angle of at least about 50 degrees, and (iii) contact between the posterior cam and the spine transitions to contact between the posterior section of the cam surface of the posterior cam and the second section of the cam surface of the spine in a second range of flexion that is greater than the first range of flexion.

An orthopaedic prosthesis comprising:

• a tibial bearing configured to be coupled to a tibial tray, the tibial bearing having a platform and a spine extending upwardly from the platform, the spine having an anterior surface and a posterior cam surface positioned opposite the anterior surface, the posterior cam surface having a substantially “S”-shaped cross-section in the sagittal plane, and
• a femoral component configured to be coupled to a surgically-prepared surface of the distal end of a femur, the femoral component including a posterior cam at a posterior end of femoral component, the posterior cam including a cam surface having a substantially “S”-shaped cross-section in the sagittal plane,
• wherein (i) the posterior cam is spaced apart and out of contact from the spine during a first range of flexion, and (ii) the cam surface of the posterior cam articulates on the posterior cam surface of the spine during a second range of flexion greater than the first range of flexion,
• wherein the posterior cam surface of the spine includes a convex cam surface and a concave cam surface, the convex cam surface of the spine is convexly curved in the sagittal plane, and the concave cam surface of the spine is concavely curved in the sagittal plane.