The Effect of Femoral Component Flexion in Total Knee Arthroplasty

» Whilst it is widely accepted that extension of the femoral component is suboptimal, there is currently no clear consensus on the optimal degree of femoral component flexion in the sagittal plane or if optimizing component flexion translates to any clinical benefit.» Flexing the femoral total knee arthroplasty (TKA) component by 0° to 3° relative to the distal anatomic axis of the femur has been demonstrated to improve restoration of posterior condylar offset, maximal knee flexion, and patellofemoral biomechanics and aid in gap balancing by reducing excessive flexion gap.» Excessive flexion of the femoral component has been associated with worse implant survival, worse patient-reported outcomes, and fixed flexion contracture.» Early evidence suggests that using robotic-assisted TKA to align the femoral component relative to each patient's individual distal anatomic axis of the femur can reduce the rate of femoral component extension and improve the proportion of patients with optimally flexed femoral components.» Robust clinical studies are needed to establish whether 0° to 3° of femoral component flexion confers any significant clinical benefit, particularly examining the role of individualized robotic-assisted TKA in achieving reproducible component positioning.