Component Rotation

The study found no statistically significant association between femoral, tibial, or combined rotation and achievement of the Oxford Knee Score minimal clinically important difference. The study did not identify any range of component rotation associated with the best clinical outcomes. Rotational variation and apparent malrotation can occur even in patients without poor clinical outcomes. External tibial rotation is associated with knee extension, foot supination, calcaneal inversion, and relative femoral internal rotation. Internal tibial rotation is associated with knee flexion, foot pronation, calcaneal eversion, and relative femoral external rotation. The screw-home mechanism illustrates tibial external rotation during knee extension. Femoral and tibial component malrotation has been proposed as a cause of pain, stiffness, dissatisfaction, and implant-related complications after total knee replacement. Tibial rotation becomes most relevant after upstream movement limitations have been addressed but pain or movement limitation remains.