Does Achieving High Flexion Increase Polyethylene Damage in Posterior-Stabilized Knees? A Retrieval Study

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Medical Engineering

Background:

• High flexion after total knee arthroplasty (TKA) is linked to concerns about increased implant damage and revision rates.
• Specialized TKA designs aim to accommodate higher degrees of flexion.

Purpose of the Study:

• To investigate if achieving high flexion (≥120°) post-TKA impacts polyethylene tibial insert damage.
• To compare surface damage and 3D deviations in retrieved inserts from high-flexion versus non-high-flexion patient groups.

Main Methods:

• Analysis of posterior-stabilized and high-flexion retrieved tibial inserts.
• Assessment of polyethylene surface damage using light microscopy.
• Measurement of 3D deviation using laser scanning.

Main Results:

• No significant differences in overall surface damage scores were observed between high-flexion and non-high-flexion groups.
• Abrasion in posterior articular regions was noted, but not exclusively in the high-flexion group.
• 3D deviations did not differ significantly between the groups, irrespective of the reason for revision.

Conclusions:

• Achieving high flexion (≥120°) did not lead to increased polyethylene insert surface damage or 3D deviation in this study.
• The findings suggest that high flexion may not adversely affect the longevity of current TKA polyethylene inserts.