Long-term Follow-up of Conventional Polyethylene in Total Hip Arthroplasty in Young Patients: Heightened Wear-related Complications are Observed at the Beginning of the Third Decade

Abstract

Background

Conventional polyethylene (CPE) was used widely in the past as a bearing surface in total hip arthroplasty (THA). As CPE THAs age and the revision burden continues to grow, it is increasingly important to understand the durability and failure mechanisms of this bearing material. Currently, such long-term data remain limited, particularly in younger, more active patients in whom wear issues are of greater concern.

Methods

We retrospectively reviewed 90 hips (77 patients) that underwent primary THA with CPE bearings on CoCr femoral heads at age ≤50 years at 20-year minimum follow-up (mean 21.6 [20–23]). We analyzed polyethylene wear rates, clinical outcomes (modified Harris Hip score, UCLA Activity score), and implant survivorship.

Results

Wear analysis revealed a median linear wear rate of 0.113mm/year (95% CI [0.102–0.148) and a median volumetric wear rate of 41.20 mm³/year (95% CI [43.5–61.0]). Modified Harris Hip scores remained 37 points above preoperative baseline (p<0.001) and UCLA scores 1.4 points above baseline (p=0.018) at 21.6-year mean follow-up. Twenty-nine hips (32.2%) were revised, 20 of which (22.2%) were wear-related at a median of 15.4 years (IQR, 11.4–19.5). Survivorship free from wear-related revision was 95.6% (95% CI [88.7–98.3]), 87.9% [78.6–93.3], 78.1% [49.6–66.5], and 61.1% [41.3–67.0] at 10, 15, 20, and 25 years.

Conclusion

Wear-related issues developed at increasingly high rates after 15 years, suggesting the need for surveillance after this time. The long-term wear and survivorship data of this study may be used as a benchmark when evaluating the performance of contemporary bearings in young, active THA patients.