Polyethylene Tibial Components
Strong evidence supports use of either all-polyethylene or modular tibial components in knee arthroplasty (KA) because of no difference in outcomes.
Surgical Management of Osteoarthritis of the Knee
Endorsed by: The Knee Society, SOMOS, AAHKS, ACR, AGS, AANA

Three high (Kalisvaart 2012, Murray 2014, Hyldahl 2001) and five moderate quality (Adalberth 2001, Gioe 2000, Muller 2006, Norgren 2004, Adalberth 2000) studies evaluated the use of all-polyethylene versus modular (metal baseplate and polyethylene insert) tibial components in knee arthroplasty. 
One high quality randomized controlled trial (Kalisvaart 2012) of cemented posterior-stabilized total knee arthroplasty demonstrated no differences in range of motion, functional outcomes, stair climbing, or revisions across three tibial designs (all-polyethylene fixed-bearing, modular metal-backed fixed-bearing, rotating-platform) at two and five years post-operatively.
In a high quality multicenter trial (Knee Arthroplasty Trial; Murray 2014) randomizing the use of all-polyethylene and modular metal-backed tibia components in the United Kingdom, 89% of patients received the allocated procedure.  There were no differences in Oxford Knee Scores or rates of complications, reoperations, and revisions at ten years post-operatively.  There was a trend towards the metal-backed group having better EQ-5D and Short Form-12 scores based on marginal estimates over the entire ten-year follow up period.
A third high quality randomized trial (Hyldahl 2001) in unicompartmental knee arthroplasty, with a focus on radiostereometric analysis (RSA) of component fixation, found no differences with respect to clinical results (Hospital for Special Surgery score) or migration of the comparative tibial components over a two-year follow-up period.
Five moderate quality (Adalberth 2001, Gioe 2000, Muller 2006, Norgren 2004, Adalberth 2000) randomized controlled trials with minimum two years of follow up demonstrated no differences with respect to clinical results (all studies used the Knee Society Score, except for Short Form-12 and Oxford Knee Score used in the study by Muller 2006) and range of motion between all-polyethylene and modular tibial components in total knee arthroplasty.  Likewise, complications and reoperations were similar between groups in all studies, and equivalent component migration was measured in four studies utilizing RSA techniques (Adalberth 2001, Muller 2006, Norgren 2004, Adalberth 2000).
The practitioner must be aware that results in the literature may be implant specific, and that surgical technique and surgeon experience with particular methods are important factors in achieving durable results.  The decision to use modularity versus a monolithic tibial design may be influenced by particular patient situations, such as metal hypersensitivity and severe bone loss.  The practitioner should be aware of the advantages and disadvantages of the two treatments methods.


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