Association of polyethylene type with revision and dislocation risk following primary total hip arthroplasty: a population-based cohort study from the Danish Hip Arthroplasty Register.

BACKGROUND AND PURPOSE: Highly cross-linked polyethylene (HXLPE) has been widely adopted to address wear in total hip arthroplasty (THA), yet population-based evidence remains limited. We aimed to evaluate the long-term risk of all-cause revision, dislocation, and cause-specific revision according to polyethylene type in primary THA.

METHODS

We conducted a population-based cohort study using data from the Danish Hip Arthroplasty Register and the Danish National Patient Register, including 48,618 patients undergoing primary THA for osteoarthritis from 2000 to 2016. Patients were followed until revision, dislocation, death, year 10, or December 2021. We compared HXLPE with non-HXLPE for patients receiving implants with 28 mm, 32 mm, and 36 mm femoral heads. We estimated standardized risk differences using targeted maximum likelihood estimation comparing polyethylene type stratified by femoral head size and standardized to age, sex, fixation, and Charlson Comorbidity Index.

RESULTS

Standardized risk differences showed favorable results for HXLPE regarding all-cause revision (-3.1%, 95% confidence interval [CI] -4.5 to -1.6), dislocation (-1.9%, CI -3.1 to -0.6), revision due to dislocation (-1.3%, CI -1.9 to -0.7), and revision due to infection (-0.9%, CI -1.3 to -0.4) for 36 mm heads, and for dislocation (-1.4%, CI -2.6 to -0.2) and revision due to aseptic loosening (-0.8%, CI -1.1 to -0.5) for 32 mm heads. There was no difference between HXLPE and non-HXPLE for any outcomes for the 28 mm group.

CONCLUSION

Among 36 mm implants, HXLPE was associated with lower risk of dislocation, all-cause revision, and revision due to infection and dislocation. Among 32 mm implants, HXLPE was associated with lower risk of dislocation and aseptic loosening revision. These findings may suggest potential advantages of HXLPE, though caution is warranted given the observational design.