Modular versus monobloc dual mobility components for primary cementless total hip arthroplasty: a systematic review and meta-analysis of implants' survival, complication rates, clinical and radiographic outcomes.

Purpose: The dual mobility cup (DMC) reduces the dislocation rates in total hip arthroplasty (THA). DMC systems include anatomical (non-modular or monoblock) (ADM) and modular dual mobility (MDM) components (Stryker Orthopaedics, Mahwah, NJ, USA). This review aims to assess differences between these two types of DMC implants concerning dislocation and revision rates, as well as patient-reported outcomes.

Methods: This systematic review and meta-analysis of studies reports data from patients undergoing primary THA using MDM and/or ADM implants. Following the PRISMA guidelines, we analyzed articles from Science Direct/Scopus, PubMed, and the Cochrane Database of Systematic Reviews. We compared dislocation rates, revisions for any reason, aseptic loosening, infections, fractures, and functional outcomes between ADM and MDM components.

Results: Eleven studies were considered eligible for further analysis. A total of 3369 patients (mean age = 65.4 years) underwent primary THA, including 3386 DMC implants. The mean follow-up for the MDM and ADM groups was 2.9 years and 3.9 years, respectively. The study revealed one dislocation in the MDM and none in the ADM. By proportion metanalysis, the review did not show statistical differences in all-cause revisions (p = 0.93, [CI [0.01;0.02]) or periprosthetic fractures (p = 0.18, CI [0.01;0.02]).

Conclusions: MDM and ADM systems, both, represent safe DM options regarding dislocation, all-causes revisions and functional outcomes.