JOA - 2026-03-02 - Journal Article
Dual Mobility versus Jumbo Head (≥ 40 mm) Following Primary Total Hip Arthroplasty: A Registry-Based Cohort Study.
Chen F, Prentice HA, Fasig BH, Paxton EW, Khatod M, Okike KM
Topics
Key Takeaway
Dual mobility confers lower dislocation risk before 4.25 years (HR 0.52) but higher risk after 4.25 years (HR 8.26) compared to jumbo heads ≥40 mm, with no significant difference in revision rates for any indication.
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Summary
This US registry-based cohort compared dislocation and revision outcomes between dual mobility and jumbo head (≥40 mm) constructs in primary THA from 2010–2024, using propensity score-weighted Cox regression and restricting inclusion to acetabular shells compatible with both options to reduce confounding by indication. Six-year dislocation incidence was 2.4% (DM) vs 2.2% (JH), with DM protective early (HR 0.52, CI 0.32–0.85) but associated with higher late dislocation risk (HR 8.26, CI 1.82–37.48) beyond 4.25 years. No significant differences were detected in all-cause revision (HR 1.22), aseptic revision (HR 1.47), or instability-related revision (HR 1.71), and most early JH dislocations were managed successfully with closed reduction.
Key Limitation
The late dislocation signal for DM (HR 8.26) is based on a small number of events at extended follow-up where registry data are sparse, making the confidence interval wide and the estimate potentially unstable.
Original Abstract
BACKGROUND
Instability remains a leading complication following primary total hip arthroplasty (THA). Large articulations enhance stability by increasing jump distance and range of motion. Dual mobility (DM) and ≥ 40 mm jumbo heads (JHs) are both large articulation options when compared to ≤ 36 mm heads, and debate exists between these two given differences in complexity, cost, and failure mechanism.
METHODS
We conducted a united States registry-based cohort study to compare DM and JH. Adults who underwent primary THA between 2010 and 2024 were included. There were 9,532 TH As (1,716 DMs and 7,816 J Hs) included. To mitigate confounding by indication and by implant generation, only cases that used DM or JH with acetabular implants compatible with both options were included. The primary outcome was dislocation; secondary outcomes were all-cause revision, aseptic revision, and revision for instability. Crude incidence was calculated at six years. Propensity score-weighted Cox proportional hazards regressions were used to evaluate revision risk.
RESULTS
Dislocation incidence was 2.4 and 2.2% for DMs and JHs, respectively. We observed a time-based difference in dislocation risk: DM was associated with a lower risk before 4.25 years (hazard ratio (HR): 0.52, 95% confidence interval (CI): 0.32 to 0.85), but a higher risk after 4.25 years (HR: 8.26, 95% CI: 1.82 to 37.48). There were no differences found in all-cause (HR: 1.22, 95% CI: 0.72 to 2.07), aseptic (HR: 1.47, 95% CI: 0.73 to 2.93), or instability-related revision risk (HR: 1.71, 95% CI: 0.79 to 3.69).
CONCLUSIONS
Use of a DM was associated with fewer early dislocations, but possibly more late dislocations, although late differences were small and later follow-up was limited. There was also no detectable difference in revisions, including for instability. While DM's marginal size advantage may avoid a small number of early closed dislocations, current large articulation options may be sufficiently similar to mitigate major revision differences. Most early JH dislocations were successfully treated closed, and conversely, the fewer early DM dislocations more often required revision.