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.

History and Systematic Review of Wear and Osteolysis Outcomes for First-generation Highly Crosslinked Polyethylene

“…Thus, concerns about the minimum thickness of polyethylene are currently perceived to limit the introduction of acetabular liners with femoral head sizes greater than 48 mm. This systematic review identified numerous studies documenting the clinical performance of HXLPEs for hip arthroplasty, but only two clinical outcomes studies were identified for HXLPE use in the knee [62,99]. The authors of both knee studies emphasized their research demonstrated the short-term safety of HXLPE in the knee.…”

“…Only two knee studies were identified in the literature search of HXLPEs in total joint arthroplasty [62,99], * Values are expressed as mean, with standard error in parentheses; 2D = two-dimensional; HXLPE = highly crosslinked polyethylene; RCT = randomized controlled trial; COH = prospective or retrospective cohort study.…”

“…These studies are nevertheless summarized briefly for completeness and to document the current state of the art in the literature for HXLPEs used in knee arthroplasty. Hodrick et al [62] retrospectively studied the clinical and radiographic outcomes for Durasul 1 and gamma-inertsterilized UHMWPE in the Natural-Knee 1 (Zimmer Inc), which is a cruciate-retaining design. One hundred consecutive patients were selected for each cohort based on the date of availability of the HXLPE at their institution in February 2001.…”

Lower prosthesis-specific 10-year revision rate with crosslinked than with non-crosslinked polyethylene in primary total knee arthroplasty

“…The first clinical study of crosslinked polyethylene was published by Hodrick et al (2008), and they reported a consecutive series of 200 Natural Knee II systems (Zimmer), comparing the first 100 cases to receive crosslinked polyethylene with the previous 100 cases using non-crosslinked polyethylene. The crosslinked polyethylene group had an average age of 67, and was followed for a minimum of 69 months, as compared to an average age of 70 and a minimum follow-up of 82 months for the non-crosslinked group.…”

“…Reduced wear was also found in crosslinked polyethylene when subjected to diverse wear models with a scratched femoral component or an unbalanced knee (Muratoglu et al 2002, 2004, Hermida et al 2008). There have, however, only been a few reports of the clinical results of highly crosslinked polyethylene in TKA (Hodrick et al 2008, Minoda et al 2009, Long et al 2012). While these studies have shown no difference in clinical or radiographic outcomes when comparing crosslinked polyethylene with non-crosslinked polyethylene, the longest follow-up was 7 years.…”