"Thicker" polyethylene bearings are associated with higher failure rates in primary total knee arthroplasty.
"Thin" modular polyethylene bearings have previously been associated with failure from wear. This study examined the influence of polyethylene thickness on survivorship in primary total knee arthroplasty (TKA). Do "thinner" or "thicker" bearings fail more? Six thousand seventy primary TKAs with a single implant design were reviewed. The failure rate in knees with bearings 14 mm or less was 0.7%, whereas the failure rate of knees with bearings 16 mm or greater was 2.3% (P < .0001; hazard ratio, 3.2). No knee was revised for polyethylene wear. Thicker bearings did not directly cause failure, but factors that lead to the insertion of a thicker bearing such as a deeper tibial resection and ligament imbalance may contribute to the observed increased failure. The significant influence of this often-unrecognized surgical variable has not been previously reported and must be carefully considered during TKA.
Berend
Michael E
ME
Joint Replacement Surgeons of Indiana Research Foundation, Center for Hip and Knee Surgery, St. Francis Medical Group, St. Francis Hospital Mooresville, Mooresville, Indiana 46158, USA.
Davis
Peter J
PJ
Ritter
Merrill A
MA
Keating
E Michael
EM
Faris
Philip M
PM
Meding
John B
JB
Malinzak
Robert A
RA
D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D007720:Knee Prosthesis; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure / Q000639:trends*; D012189:Retrospective Studies; D013997:Time Factors
D020959:Polyethylene