Sixty-seven ultrahigh molecular weight @entity691 tibial inserts from cementless total knee arthroplasties were retrieved at autopsy and revision surgery and analyzed for evidence of articular and nonarticular surface wear after a mean implantation time of 62.8 months (range, 4-131 months). @entity691 cold flow and abrasive wear on the nonarticular insert surface (undersurface) were assigned a wear severity score (Grade 0-4). The severity of articular wear was assessed quantitatively and graded. Corresponding prerevision radiographs were evaluated for evidence of tibial metaphyseal @entity3061 and @entity3061 around tibial fixation screws. Exact nonparametric conditional inference methods were used to establish correlations between different variables and the occurrence of tibial metaphyseal @entity3061 . Severe Grade 4 wear of the tibial insert undersurface was associated with tibial metaphyseal @entity3061 or @entity3061 around fixation screws. Time in situ statistically was related to Grade 4 undersurface wear and tibial metaphyseal @entity3061 . The occurrence of @entity3061 was not related statistically to articular wear severity, insert thickness, or implant type. The main articulation between the femoral implant and ultrahigh molecular weight @entity691 insert has been assumed to be the primary source of @entity691 debris contributing to @entity3061 and @entity348 implant failure. The undersurface of the insert is an additional source of @entity691 debris contributing to tibial metaphyseal @entity3061 . To lessen @entity691 debris produced at this modular interface, the tibial implant locking mechanism should fix the insert firmly to the metal backing to decrease relative micromotion. Because motion between the insert and metal backing may be inevitable, the wear characteristics of the inner tray surface should be optimized to minimize @entity3356 production at this other articulation.

Tibial insert undersurface as a contributing source of @entity691 XXXX .

@entity691 :: ('MESH:D020959', 'Chemical') :: ['Polyethylene', 'polyethylene'] @entity3061 :: ('MESH:D010014', 'Disease') :: ['tibial osteolysis', 'osteolysis'] @entity348 :: ('MESH:C535338', 'Disease') :: ['total knee arthroplasty'] @entity3356 :: ('MESH:D057085', 'Disease') :: ['wear debris']
@entity3356 :: (MESH:D057085,Disease) :: ['wear debris']
