Based on our findings, crosslinked polyethylene liners demonstrate substantially reduced wear and osteolysis compared to non-crosslinked polyethylene,” reported Charles A. Engh Jr, MD, to attendees at the 2011 American Association of Hip and Knee Surgeons annual meeting. Dr. Engh’s paper, “A Prospective, Randomized Study of Crosslinked and Non-crosslinked Polyethylene for Total Hip Arthroplasty at 10-Year Follow-up,” received the Lawrence D. Dorr Award as the most outstanding paper in surgical techniques and technologies.
Reduced wear? Or not?
Dr. Engh explained that crosslinked liners were introduced with the goal of substantially reducing polyethylene wear. In 1999, his institution initiated a prospective study to compare outcomes for total hip arthroplasty (THA) patients who received either a conventional non-crosslinked liner or a polyethylene liner that had been crosslinked with 5.0 mrad of gamma-irradiation and heat-treated to eliminate free radicals.
THA patients were randomized to receive either conventional liners (n = 114) or crosslinked liners (n = 116). The mean age of the patients at surgery was 62.0 years for those in the conventional liners cohort and 62.5 years for participants in the crosslinked liners group. Based on the data that was available at the time of his presentation, 30 patients (31 THAs) had died with less than 9 years of follow-up and were excluded from the study results. At 10-year follow-up, 12 THAs had undergone reoperations.
The researchers used various techniques to evaluate implant survivorship, measure polyethylene wear, and evaluate osteolysis.
“At latest follow-up, we noted eight liner exchanges related to wear and osteolysis among the patients in the conventional group,” said Dr. Engh. “There were none among patients in the crosslinked group.”
When revision for wear-related complications was used as an endpoint, conventional liners had a 10-year survivorship rate of 94.6 percent; in the crosslinked group, 10-year survivorship was 100 percent. The incidence of osteolysis with an area of at least 1.5 square centimeters was 25 percent for conventional liners and 0 percent for crosslinked liners.
“Our findings show that, at 10-year follow-up, the improved wear performance of crosslinked liners has resulted in a significantly reduced incidence of revision,” said Dr. Engh.
This is an update of a paper presented at the AAOS 2011 Annual Meeting; the online version of this article includes a link to the abstract. Dr. Engh’s coauthors on the paper are: Robert H. Hopper Jr, PhD (DePuy, A Johnson & Johnson Company); Cathy Huynh, BS (no conflicts); Henry Ho, MS (no conflicts); Supatra Sritulanondha, MPH (no conflicts); and Charles A. Engh Sr, MD (DePuy, A Johnson & Johnson Company; Smith & Nephew, Stryker; Alexandria Research Technology, Medtronic). Dr. Engh Jr reports ties to DePuy, A Johnson & Johnson Company; Stryker; Zimmer; and Smith & Nephew.
Peter Pollack is a staff writer for AAOS Now. He can be reached at firstname.lastname@example.org