BJJ - 2026-09-01 - Journal Article
Patient, surgeon, and institutional variation in dual-mobility component use in primary total hip arthroplasty : a retrospective cohort study using data from the National Joint Registry Study.
Zucker BE, Howard JT, Whitehouse MR, Judge A
Topics
Key Takeaway
Surgeon-level factors (32.4%) and institutional factors (22.9%) account for more than half of variation in dual-mobility THA use, while patient-level characteristics explain only ~10% of variance across 238,455 primary THAs.
Summary Depth
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Summary
Using National Joint Registry data linked with Hospital Episode Statistics (2018–2022), cross-classified multilevel logistic regression partitioned variation in DM-THA use among English surgeons and institutions. Surgeon-level factors explained 32.4% and institutional factors 22.9% of variation, versus ~10% attributable to patient characteristics. The full model explained 59.8% of total variation, and findings held in high-volume surgeon subgroup analysis.
Key Limitation
Administrative HES coding cannot capture surgical approach, abductor status, or preoperative instability risk scoring—the primary clinical drivers of DM-THA indication—meaning patient-level variance is systematically underestimated.
Original Abstract
AIMS
The aim of this study was to quantify the contribution of patient-, surgeon-, and institution-level factors to variation in dual-mobility component use in primary total hip arthroplasty (DM-THA) in England. We sought to determine whether current patterns reflect appropriate patient selection or unwarranted practice variation. We hypothesized that surgeon- and institution-level factors account for a greater proportion of variation in DM-THA use than patient-level characteristics.
METHODS
We analyzed 238,455 primary THAs recorded in the National Joint Registry which were linked with Hospital Episode Statistics for England between 1 January 2018 and 31 December 2022. Using cross-classified multilevel logistic regression modelling, we partitioned variation in DM-THA use attributable to patient, surgeon, and institutional factors. Patient risk factors were included as fixed effects, with random effects specified for surgeons and hospitals to account for clustering.
RESULTS
Of the total cohort, 7,032 underwent DM-THA. These patients were older, more frail, and more frequently treated for neck of femur fractures. Surgeon-level factors explained 32.4% and institutional factors 22.9% of variation in DM-THA use. Patient-level factors accounted for approximately 10% of the variance (marginal R² = 0.10), while the full model explained 59.8% of variation (conditional R² = 0.598). Findings were consistent in analyses restricted to high-volume surgeons.
CONCLUSION
Variation in DM-THA use is predominantly driven by surgeon and institutional practice rather than patient characteristics. Prognostic tools which can identify patients at high dislocation risk, to guide inclusion criteria for targeted randomized trials, are needed to establish evidence-based guidance for DM implant selection and reduce unwarranted practice variation.