Lieberman, Jay R.

AimsModular dual-mobility (DM) articulations are increasingly used during total hip arthroplasty (THA). However, concerns remain regarding the metal liner modularity. This study aims to correlate metal artifact reduction sequence (MARS)-MRI abnormalities with serum metal ion levels in patients with DM articulations.MethodsA total of 45 patients (50 hips) with a modular DM articulation were included with mean follow-up of 3.7 years (SD 1.2). Enrolled patients with an asymptomatic, primary THA and DM articulation with over two years’ follow-up underwent MARS-MRI. Each patient had serum cobalt, chromium, and titanium levels drawn. Patient satisfaction, Oxford Hip Score, and Forgotten Joint Score-12 (FJS-12) were collected. Each MARS-MRI was independently reviewed by fellowship-trained musculoskeletal radiologists blinded to serum ion levels.ResultsOverall, two patients (4.4%) had abnormal periprosthetic fluid collections on MARS-MRI with cobalt levels > 3.0 μg/l. Four patients (8.9%) had MARS-MRI findings consistent with greater trochanteric bursitis, all with cobalt levels < 1.0 μg/l. A seventh patient had a periprosthetic fluid collection with normal ion levels. Of the 38 patients without MARS-MRI abnormalities, 37 (97.4%) had cobalt levels < 1.0 μg/l, while one (2.6%) had a cobalt level of 1.4 μg/l. One patient (2.2%) had a chromium level > 3.0 μg/l and a periprosthetic fluid collection. Of the 41 patients with titanium levels, five (12.2%) had titanium levels > 5.0 μg/l without associated MARS-MRI abnormalities.ConclusionPeriprosthetic fluid collections associated with elevated serum cobalt levels in patients with asymptomatic DM articulations occur infrequently (4.4%), but further assessment is necessary due to implant heterogeneity.Cite this article: Bone Joint J 2024;106-B(3 Supple A):89–96.

Aims Dual mobility (DM) bearings are an attractive treatment option to obtain hip stability during challenging primary and revision total hip arthroplasty (THA) cases. The purpose of this study was to analyze data submitted to the American Joint Replacement Registry (AJRR) to characterize utilization trends of DM bearings in the USA. Methods All primary and revision THA procedures reported to AJRR from 2012 to 2018 were analyzed. Patients of all ages were included and subdivided into DM and traditional bearing surface cohorts. Patient demographics, geographical region, hospital size, and teaching affiliation were assessed. Associations were determined by chi-squared analysis and logistic regression was performed to assess outcome variables. Results A total of 406,900 primary and 34,745 revision THAs were identified, of which 35,455 (8.7%) and 8,031 (23.1%) received DM implants respectively. For primary THA, DM usage increased from 6.7% in 2012 to 12.0% in 2018. Among revision THA, DM use increased from 19.5% in 2012 to 30.6% in 2018. Patients < 50 years of age had the highest rates of DM implantation in every year examined. For each year of increase in age, there was a 0.4% decrease in the rate of DM utilization (odds ratio (OR) 0.996 (95% confidence interval (CI) 0.995 to 0.997); p < 0.001). Females were more likely to receive a DM implant compared to males (OR 1.077 (95% CI 1.054 to 1.100); p < 0.001). Major teaching institutions and smaller hospitals were associated with higher rates of utilization. DM articulations were used more commonly for dysplasia compared with osteoarthritis (OR 2.448 (95% CI 2.032 to 2.949); p < 0.001) during primary THA and for instability (OR 3.130 (95% CI 2.751 to 3.562) vs poly-wear; p < 0.001) in the revision setting. Conclusion DM articulations showed a marked increase in utilization during the period examined. Younger patient age, female sex, and hospital characteristics such as teaching status, smaller size, and geographical location were associated with increased utilization. DM articulations were used more frequently for primary THA in patients with dysplasia and for revision THA in patients being treated for instability. Cite this article: Bone Joint J 2020;102-B(7 Supple B):27–32.