Highly crosslinked polyethylene is safe for use in total knee arthroplasty

Abstract

Highly cross-linked polyethylene (XLPE) has been used with good initial success in hip arthroplasty to reduce wear. However, the process of crosslinking reduces fracture toughness, raising concerns as to whether it can be safely used in total knee arthroplasty (TKA). We therefore asked whether XLPE can be used safely in TKA. We performed a retrospective review of 100 subjects receiving XLPE and compared them to 100 subjects who received standard polyethylene in the setting of TKA. The standard polyethylene group had a mean age of 70 with a minimum follow up of 82 months. The highly cross-linked polyethylene group had a mean age of 67 and a minimum follow up of 69 months (mean, 75 months; range, 69-82 months). On radiographic review, the standard group demonstrated 20 TKAs with radiolucencies; 4 of these had evidence of a loose tibial component. The standard group required three revisions related to loose tibial components. The XLPE group had 2 subjects that demonstrated radiolucencies on radiograph and no subjects with evidence of tibial loosening. There were no reoperations related to osteolysis. The data suggest XLPE in TKA can be used safely at least short- to midterm. Our study provides an impetus for further long-term investigation.

Level of evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Figures

Fig. 1

Demonstrated in the figure is the AP radiograph of a patient with osteolysis. The right knee underwent TKA 5.5 years ago with conventional polyethylene. The left knee underwent TKA 5 years ago with highly crosslinked polyethylene. This figure shows a radiographic difference in the amount of lysis between the two knees.

Fig. 2

Figure 2 is an intraoperative photograph of highly crosslinked polyethylene at 5 years showing no observable wear. The reason for revision was ligamentous laxity.

Fig. 3

Demonstrated are the Kaplan-Meier failure probabilities for revision for loose tibial component. There was not a significant difference in revisions between the groups (highly crosslinked: 0 revisions; standard polyethylene: 3 revisions, log-rank test, p = 1.00).