Comparison of a Metal Backed Fixed-Bearing Tibial Baseplate and an All-Polyethylene Tibia in Total Knee Arthroplasty

This study is designed to compare prospectively, in a randomized Level 1 evidence fashion,
the clinical, functional, and radiographic results of a modular polished tibial (MPT) tray
with a moderately cross-linked polyethylene (XLK) insert to an all-polyethylene tibial (APT)
design with GVF polyethylene. Comparing these two designs will afford us information in the
following areas:

1. Does a MPT/XLK design have improved wear characteristics over a nonmodular APT/GVF
design?

2. Is there a clear clinical advantage to the MPT/XLK design in certain patient
populations that justify its use over the APT/GVF design?

Answering these questions will allow surgeons to use both designs appropriately in different
demand populations.

This study is designed to address the questions of whether an MPT/XLK design offers
improvement in wear characteristics, Knee Society scores, KOOS, WOMAC, SF-36, or
radiographic measures, over an APT design. The investigator's primary hypothesis is that
there will be no difference in these outcome measures at a minimum two year follow-up. A
secondary hypothesis based on the long-term follow-up of this group, up to twenty years, is
that there will be no difference in implant survival.