Trends in Dual Mobility Cup Use and Outcomes in Primary and Revision Hip Arthroplasty: A Nationwide Database Study.

BACKGROUND

Dual mobility cups (DMCs) have emerged as a promising option for enhancing hip stability in primary and revision total hip arthroplasty (THA). In this study, we aimed to determine the trends in DMC utilization, compare the outcomes of DMCs with those of conventional cups in primary THA, and assess DMC outcomes in revision THA.

METHODS

We collected data on all primary and revision THAs performed from 2015 to 2022 based on procedure codes from the Korean Health Insurance Review and Assessment database. Revision THAs included both stem-and-cup revisions and cup-only revisions. Univariate and multivariable analyses were conducted to identify the baseline characteristics influencing DMC usage. Propensity score matching was applied to compare periprosthetic complications (dislocation, periprosthetic fracture, periprosthetic joint infection, and revision) between patients receiving DMCs and those receiving conventional cups.

RESULTS

Among 70,760 primary THAs, 7,670 utilized DMCs, whereas 751 of 3,595 revision THAs adopted DMCs, reflecting an increasing trend up to 25.8% and 28.7% in 2022, respectively. In primary THA, DMC use increased significantly in patients aged 60 years and older, with univariate analysis indicating an increased use in patients with previous lumbar spine fusion, heart failure, diabetes, stroke, and hemiplegia. However, after adjusting for age, only age remained significant, with a 3% increase in the likelihood of DMC use in primary THA per year. Additionally, both DMC and conventional cups showed an age-related increase in dislocation rates, although the overall dislocation rate remained significantly lower in the DMC group compared to the conventional cups. Remarkably, 37.3% of cup revisions were performed using DMC. The Kaplan-Meier curve revealed a 3-year survival rate of 94.6% for re-revision in revision THAs using DMCs.

CONCLUSIONS

DMC use increased with age and was used in up to 26% of primary THAs and 29% of revision THAs by 2022. In primary THA, DMC significantly reduced dislocation rates compared to conventional cups without increasing other periprosthetic or medical complications. DMCs also showed favorable outcomes in revision THAs, supporting their broader utilization in both primary and revision THAs.