Multicenter Study of Highly Cross-linked vs Conventional Polyethylene in Total Knee Arthroplasty.

Background: Despite substantial interest and use of highly cross-linked polyethylene (HXLPE) in total knee arthroplasty (TKA), outcomes remain largely unknown. The purpose of this study is to compare HXLPE and conventional polyethylene at 4- to 5-year follow-up.

Methods: A prospective multicenter study of 307 posterior-stabilized TKAs (168 conventional and 139 HXLPE) was performed. Short-Form-6D, Short-Form 36, Knee Society Score, Lower Extremity Activity Score, health-related quality of life outcomes, and radiographs were collected preoperatively and at routine postoperative intervals.

Results: Two hundred twenty-four patients obtained a minimum 4- to 5-year follow-up for analysis. There were no osteolysis or polyethylene failures in either group. Although both conventional and HXLPE poly groups showed significant improvements in all measures from preoperative baselines (P < .05), the XLPE group had slightly greater mean Knee Society Score function (P = .04), Lower Extremity Activity Score (P = .03), and Short-Form 36 Physical Composite Score (P = .03) scores and a greater improvement in Short-Form 6D health-related quality of life of 0.16 points (d = 1.02, 95% CI: 0.01-1.11) at latest follow-up.

Conclusion: The study findings support comparative safety and outcomes of HXLPE related to mechanical failure or osteolysis in the midterm. However, longer-term follow-up is warranted to assess whether wear and mechanical properties of HXLPE are maintained in vivo.