What is the knee center location and why is it significant to CORI registration?

What is the knee center location and why is it significant to CORI registration?

• A. Femur: The most distal point along the femoral mechanical axis; Tibia: Center of the ACL bundle; Significance: establishes the femoral mechanical axis
• B. Femur: The most proximal point along the femoral mechanical axis; Tibia: Center of the ACL bundle; Significance: establishes the femoral mechanical axis
• C. Femur: The most distal point along the femoral mechanical axis; Tibia: Center of the PCL bundle; Significance: establishes the tibial axis
• D. Femur: The center of the femoral head; Tibia: Center of the ACL bundle; Significance: establishes the tibial axis

Answer: (A)

The most important idea is that CORI registration uses a reproducible knee center landmark that ties together the femur and tibia to define the knee’s mechanical axis. The knee center on the femur is taken as the most distal point along the femoral mechanical axis, which corresponds to the knee’s end on the femoral side. On the tibia, locating the center of the ACL bundle provides a consistent tibial landmark related to the ACL footprint. Together, these landmarks anchor the knee in the navigation space and establish the femoral mechanical axis, which is crucial for accurate instrument tracking and implant alignment. Using any alternative distal or proximal femoral point, a tibial landmark from a different ligament (like the PCL), or the center of the femoral head would not provide the same reliable reference for defining the knee’s axis.

The most important idea is that CORI registration uses a reproducible knee center landmark that ties together the femur and tibia to define the knee’s mechanical axis. The knee center on the femur is taken as the most distal point along the femoral mechanical axis, which corresponds to the knee’s end on the femoral side. On the tibia, locating the center of the ACL bundle provides a consistent tibial landmark related to the ACL footprint. Together, these landmarks anchor the knee in the navigation space and establish the femoral mechanical axis, which is crucial for accurate instrument tracking and implant alignment. Using any alternative distal or proximal femoral point, a tibial landmark from a different ligament (like the PCL), or the center of the femoral head would not provide the same reliable reference for defining the knee’s axis.