No Decrease in Early Survivorship of Dual Mobility Implants in Primary Total Hip Arthroplasty.

Background: Dual mobility (DM) implants in primary total hip arthroplasty (THA) have gained recent popularity; however, safety concerns persist. The purpose of this study was twofold: 1) assess trends in DM implant adoption; and 2) evaluate the impact of modular DM implants on dislocation and all-cause revision rates at short-term follow-up.

Methods: This retrospective study identified patients in our institutional arthroplasty database who underwent primary posterior approach THA for degenerative conditions from November 2013 to December 2020. Patients undergoing primary THA for fracture were excluded. Patients were divided into two cohorts: modular DM and non-DM implants. Annual DM utilization and dislocation rates were recorded. Patient records were reviewed to determine implant selection and identify indications for dislocations and reoperations.

Results: Institutional adoption was rapid, increasing from 3.4% in 2013 to 47.1% in 2020. Of the 4548 primary THA cases from 2013 to 2020, 2859 (62.9%) had minimum one-year follow-up data for inclusion. There were 724 (25.3%) with DM implants and 2135 (74.7%) with non-DM implants. The DM group had a significantly lower dislocation rate (0.14% vs 0.84%,  = .04), with similar all-cause revision rates (2.49% vs 2.72%,  = .74) at one-year follow-up. No cases of DM-specific complications (metallosis or intraprosthetic dislocations) were noted.

Conclusions: From 2013 to 2020, DM implant utilization in primary THA steadily increased. Use of modular DM implants is associated with a decreased dislocation rate without compromised survivorship at one-year follow-up when compared to non-DM implants. No instances of modular DM-specific complications were identified; however, longer-term surveillance is necessary to verify these findings.

Level Of Evidence: Prognostic Level III.