PI/study coordinator retired due to personal family health matters; study sponsor withdrew funding. Study terminated and no data collected or analyzed

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.

Summary is detailed

Inclusion Criteria:

• generally accepted clinical and radiographic criteria for total knee arthroplasty

Exclusion Criteria:

• Significant angular or bony deformity necessitating structural bone grafting or more extensive modular designs will be excluded at the discretion of the principle investigator
• Routine contraindications to TKA (active sepsis, Charcot arthropathy)
• Patients whose mental function preclude them from responding to our standard questionnaires