Abstract
It has been reported that patients feel a degree of dissatisfaction after total knee arthroplasty (TKA) because of a sensation of instability during knee flexion. The ATTUNETM Total Knee System (DePuy) has been newly developed to stabilize and reproduce smooth motion during knee kinematics. This system offers many sizes of implants and inserts according to individual patient variations. We evaluated the kinematics of this type of knee implant with small variations of the inserts using an intraoperative navigation system. ATTUNETM TKA was performed in 3 knees with osteoarthritis. These TKAs were evaluated for knee kinematics, especially flexion/extension gap (FEG), anterior-posterior translation (APT), and axial rotation (AR), using an imageless navigation system (Kolibri). In the cruciate retaining (CR) type, no medial pivot motion was observed, and thus the kinematics showed a bicondylar roll-back pattern when the joint gap was tight. However, a medial pivot and decreased bicondylar roll-back pattern was shown when the joint gap was reduced with a 1-mm thinner insert to regulate the appropriate ligament balancing, even in the same knee. In the posterior stabilized (PS) type, the knee kinematics showed a small APT and AR, and moreover, FEG was even throughout the whole range of motion.
