Over a decade of research confirmed that the ACL deficient total knee has very different kinematics from an ACL intact normal knee [1,2]. The 3DKnee is based on data from insert retrievals, tibial plateau analysis, and fluoroscopic review (shown in Figures A and B) which concluded that an ACL deficient knee has a lateral rotational bias. The 3DKnee has a spherical lateral compartment that restores knee stability near extension, but provides for increasing laxity and posterior condylar rollback in deeper flexion. A curved and wide medial compartment provides excellent load distribution throughout flexion. The design has performed successfully in vivo with excellent Knee Society scores [3].
