Dual Mobility Hip Implants More Common in Young Patients?

Noting the uptick in enthusiasm in the U.S. for dual mobility (DM) bearings in total hip arthroplasty (THA)—and the paucity of long-term data—a team from the Keck School of Medicine of the University of Southern California, Department of Orthopaedic Surgery in Los Angeles took it upon themselves to investigate.

Their study, “Trends in the use of dual mobility bearings in hip arthroplasty: an analysis of the American Joint Replacement Registry,” appears in the June 30, 2020 edition of The Bone & Joint Journal.

The researchers looked at all primary and revision THAs reported to the American Joint Replacement Registry from 2012 to 2018, separating out dual mobility bearings from the traditional bearing surface cohorts.

The researchers pulled together data for a total of 406,900 primary and 34,745 revision THAs.  Of those, the team found that 35,455 (8.7%) primaries and 8,031 (23.1%) revisions received dual mobility implants, respectively.

The research team reported that for primary total hip arthroplasties, dual mobility usage increased from 6.7% in 2012 to 12.0% in 2018. For revision total hip arthroplasties, the team found that dual mobility use increased from 19.5% in 2012 to 30.6% in 2018.

Patients under 50 years of age, the research team found, had the highest rates of dual mobility implantation in every year examined. And, further, for each year of increase in patient age, the research team noticed a 0.4% decrease in the rate of dual mobility use. Females were more likely to receive a dual mobility implant than males. Major teaching institutions and smaller hospitals had higher rates of utilization. And, in terms of indications, the team noticed that dual mobility articulations were used more commonly for dysplasia when compared with, for example, osteoarthritis during primary THA and for instability in the revision setting.

Co-author Nathanael Heckmann, M.D. told OTW, “The most important result was the finding that dual mobility articulations were used most frequently in younger patients. This is particularly concerning as younger patients have the potential to live with these implants for several decades.”

“Future work should focus on long term outcomes of these articulations in order to determine who stands to benefit the most from these newer implants.”