Product Description The Natural-Knee II System is a semiconstrained total knee prosthesis consisting of three anatomically designed components: the femoral, tibial, and patellar prostheses. There are four available configurations: Primary (primary femoral, congruent or ultracongruent tibial insert, primary or modular cemented tibial baseplate, Natural-Knee II patella) Revision (revision femoral with primary tibial baseplate or primary femoral with revision tibial baseplate, congruent or ultracongruent tibial insert, Natural-Knee II patella) Posterior Stabilized (posterior stabilized or revision femoral, posterior stabilized tibial insert, primary or modular cemented tibial baseplate, Natural-Knee II patella) Constrained (constrained femoral component, constrained or posterior stabilized condylar tibial insert, constrained or modular cemented tibial baseplate, Natural-Knee II patella)