Total hip arthroplasty (THA) is an effective operation for the management of end-stage hip osteoarthritis, but long-term success can be limited by wear of the polyethylene bearing surface. Cross-linking conventional polyethylene has resulted in lower wear rates and a reduction in bone lysis in both laboratory and clinical studies. The aim of this study was to compare the rates of revision between cross-linked polyethylene (XLPE) and conventional non-cross-linked polyethylene (CPE) at 16 years after THAs performed for the treatment of osteoarthritis.
We performed an observational study of data, from a national registry, on all patients who underwent THA for osteoarthritis in Australia from 1999 through December 31, 2016. The outcomes of THAs performed with CPE were compared with those of THAs performed with XLPE, along with an analysis of the effect of age, sex, femoral head size, the method of acetabular and femoral component fixation, and the reasons and types of revision. The principal outcome measure was the time to the first revision, determined using Kaplan-Meier estimates of survivorship.
CPE was used in 41,171 procedures, and XLPE was used in 199,131. The mean ages of the men and women treated with CPE were 70.0 years (standard deviation [SD] = 9.9 years) and 72.5 years (SD = 9.7 years), respectively, whereas the men and women who received XLPE were slightly younger (mean age, 68.6 years [SD = 10.3 years] and 70.7 years [SD = 9.9 years], respectively. XLPE was associated with a lower rate of revision than CPE at 6 months, and this difference became more apparent with time. The 16-year cumulative percentage of revisions of the primary THAs was 11.7% (95% confidence interval [CI] = 11.1% to 12.3%]) in the CPE group and 6.2% (95% CI = 5.7% to 6.7%) in the XLPE group. The hazard ratio at 9 years was 3.02 (p = 0.001).
The use of XLPE has resulted in a significant reduction in the rate of revision at 16 years following THA for osteoarthritis. This evidence suggests that the longevity of THA is likely to be improved, which may enable younger patients to undergo surgery, confident of a reduced need for revision in the long term.
Level of Evidence:
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.