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)
Porous femoral components are manufactured from cobalt-chromium-molybdenum alloy (CoCrMo) and Cancellous- Structured Titanium™ (CSTi™) Porous Coating. Non-porous femoral components, revision posterior stabilized bars, Constrained Knee System femoral spacers and revision femoral and adapter spacers are manufactured from CoCrMo alloy.
Porous tibial baseplates are manufactured from Ti-6Al-4V alloy and CSTi Porous Coating. Modular cemented tibial baseplates and spacers are manufactured from CoCrMo alloy. Natural-Knee II revision stems are manufactured from CoCr. All other tibial baseplates, tibial baseplate spacers and revision fluted stems are manufactured from Ti-6Al-4V alloy.
All-polyethylene tibial components, which are made from ultra-high molecular weight polyethylene (UHMWPE) and contain titanium x-ray markers, are also available. Cancellous bone screws for use with tibial baseplates are made from commercially pure titanium.
Natural-Knee II patella components are available in either all-polyethylene or metal-backed versions. The all polyethylene patella is made from UHMWPE or Durasul ® Highly Crosslinked Polyethylene. The metal-backed patella is made from a UHMWPE dome attached to a circular Ti-6Al-4V alloy baseplate with CSTi Porous Coating. Articular surface components are manufactured from UHMWPE or Durasul polyethylene.