Can Modular Dual Mobility Devices Reduce Dislocations after Revision THA?

    Repeat dislocation is one of the most common reasons for patients to undergo revision total hip arthroplasty (THA), but, unfortunately, dislocation can also be a significant issue following the revision procedure.

    Modular dual mobility devices have been proposed as a solution for improving stability in revision THA patients. Are they really a good option in this patient population?

    Research presented at the 2018 American Association of Hip and Knee Surgeons Annual Meeting suggests that the answer is yes: Data from a multicenter retrospective study found a low rate of instability, with good functional improvement and a low rate of reoperation.

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    “Although the concept of dual mobility was originally developed in France in the 1970s, the technology is relatively new in the United States,” said Geoffrey H. Westrich, MD, from Hospital for Special Surgery in New York and one of the study authors. “Our study found that the newer technology with modular dual mobility components offered increased stability, lowering the risk of dislocation without compromising hip range of motion in patients having a revision surgery.”

    The study included among the 370 patients (221 females, 149 males) with an average age of 65.8 years who underwent revision THA with a modular dual mobility device between April 2011 and April 2017. The analysis included 315 patients who had a minimum follow-up of 1 year (average follow-up, 3.3 years).

    Clinical, radiographic, and patient reported-outcome data were collected, including:

    • Harris Hip Scores
    • Reoperations
    • Acetabular component loosening
    • Infection
    • Periprosthetic fracture
    • Acetabular component malposition
    • Liner seating
    • Screw placement

    “Currently, there are few large-scale outcome studies on the modular dual mobility device in revision hip replacement,” Dr. Westrich said. “We set out to determine the rate of dislocation and the need for another surgery following revision hip replacement using this implant and report on the functional outcomes.”

    After revision with the modular dual mobility device, Harris Hip Scores improved from 54.8 to 83.4 (P<0.001). Only 30 patients (9.5%) had to undergo reoperation for the following reasons:

    • Instability: 9 (2.9%)
    • Acetabular component loosening: 8 (2.5%)
    • Infection: 6 (1.9%)
    • Periprosthetic fracture: 4 (1.3%)
    • Acetabular component malposition: 1 (0.3%)
    • Improper liner seating: 1 (0.3%)
    • Improper screw placement: 1 (0.3%)

    “At the latest follow-up, we found that surgery with thedual mobility implant resulted in a very low rate of instability for the revision patients, namely 2.9%, with good functional improvement and a low rate of reoperation,” Dr. Westrich said. “While longer-term follow-up is needed to fully assess the newer device, in our study there was clearly a benefit provided by the dual mobility implant in the first few years following revision surgery.”


    Huang RC, Malkani AL, Mont MA, Hozack WJ, Harwin SF, Westrich GH. Multicenter Evaluation of a Modular Dual Mobility Construct for Revision Total Hip Arthroplasty (Paper #12). Presented at the 2018 Annual Meeting of the American Association of Hip & Knee Surgeons, November 1-4, 2018, Dallas, Texas.