Symmetry versus asymmetry in the design of total knee femoral components -An unresolved controversy

Despite the excellent success of earlier total knee replacement designs suc h as the Total Condylar Knee (Johnson & Johnson Raynham, MA), which had a s ymmetrical femoral component, the majority of modern designs feature a more anatomic and asymmetric femoral prosthesis. A raised lateral phalange, an angled trochlear groove, or both are thought to improve patellar tracking. Laboratory studies, however, suggest that surgical technique may be the dom inant factor in determining patellofemoral kinematics. Component design has not been proven to be significant. A prosthesis with asymmetric femoral co mponents may cost more. The literature reviewed in this article finds no ad vantage to the use of asymmetric versus symmetrical femoral components in t otal knee replacement.