Abstract
The articular design of a polyethylene insert influences the kinematics and overall
function of a total knee arthroplasty (TKA). Standard symmetric posterior-stabilized
and cruciate-retaining polyethylene designs have a long track record of high patient
satisfaction and longevity in TKA. However, the number and variety of polyethylene
inserts and articulations have continued to evolve in an attempt to better replicate
native knee kinematics or provide additional constraint. Ultracongruent polyethylene
designs have been touted as increasing stability while maintaining the benefits of
cruciate-retaining knees. Medial pivot and lateral/dual pivot polyethylene designs
were introduced to mimic more normal knee kinematics with regard to femoral rollback.
Further, with increasing recognition of knee instability as a cause for persistent
symptoms and revision TKA, the utilization of midlevel constraint polyethylene inserts
has been increasing, with multiple implant companies offering an insert design with
increased constraint for use with a primary femoral component. In this rapidly evolving
arena in with a myriad of options available, surgeons should be knowledgeable about
the design concepts and their applicable uses for specific patient scenarios. Future
research is needed to better understand whether a particular type or design of polyethylene
insert and articulation leads to improved patient reported outcomes, improved replication
of knee kinematics, and long-term durable implant survivorship.
Keywords
knee arthroplasty - polyethylene design - primary total knee - knee design - polyethylene
component
