Evaluation of the Contact Area in Total Knee Arthroplasty Designed for Deep Knee Flexion

Total knee arthroplasty (TKA) implants are becoming an interesting subject in implant design research and development activities due to their complexity. They should be able to facilitate knee movement while supporting body weight during daily usage. Meanwhile, incidents such as hyperflexion in TKA implants outside their designated configuration can lead to subluxation and dislocation in this study, a polyethylene component of a posterior-stabilized right knee joint implant was developed to facilitate a high range of motion (ROM). Finite element analysis (FEA) was used to analyze the contact area on the polyethylene component. FEA was used to simulate weight-bearing conditions at 0°, 30°, 60°, 90°, 120°, and 150° of knee flexion. The modified polyethylene component resulted in better performance in terms of contact area, especially at 120° of knee flexion. The two dominant contact areas on the polyethylene component were 733 mm² at 0° of knee flexion and 576 mm² at 120° of knee flexion. Furthermore, the current design of the polyethylene component can maintain a contact area of 65 mm² at 150° of knee flexion. The current design is expected to accommodate deep knee flexion movement in daily activities and reduce the possibility of subluxation and dislocation at the polyethylene component during deep knee flexion. In addition, a large contact area can reduce the potential wear on or fracture of the polyethylene component. Finally, the result of FEA was validated using a simulator of knee kinematic motion; there was no indication of subluxation and dislocation at any degree of knee flexion.