Surface Damage Is Not Reduced With Highly Crosslinked Polyethylene Tibial Inserts at Short-term

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Wear Analysis

Background:

• Highly crosslinked ultrahigh-molecular-weight polyethylene (XLPE) is used in hip arthroplasty to reduce wear.
• Its benefits in total knee arthroplasty (TKA) compared to conventional polyethylene (PE) are not well-established.

Purpose of the Study:

• To compare surface damage and dimensional changes between retrieved XLPE and conventional PE tibial inserts in TKAs.
• To determine if differences in surface damage or dimensional alterations exist between these two polyethylene materials.

Main Methods:

• Matched retrieval analysis of 44 XLPE and 44 conventional PE TKA tibial inserts from four manufacturers.
• Assessment of surface damage via subjective grading and digital mapping.
• Quantification of 3D dimensional changes using laser scans compared to pristine components.

Main Results:

• No clinically significant differences in surface damage scores or percent damaged areas were found between XLPE and conventional PE inserts (p > 0.05).
• XLPE inserts demonstrated significantly greater articular surface dimensional changes compared to conventional PE (p = 0.03).
• Dimensional change patterns varied by implant design, not material, with XLPE showing greater deviations.

Conclusions:

• There is no discernible difference in surface damage between matched XLPE and conventional PE TKA inserts.
• Increased dimensional changes in XLPE may suggest larger contact areas, potentially explaining improved performance in simulator studies.
• Caution is advised when adopting more expensive XLPE, as long-term clinical benefits beyond current PE performance require further investigation.