Two-Year Outcomes of Novel Dual-Mobility System in Revision Total Hip Arthroplasty

Background: Revision Total Hip Arthroplasty (rTHA) is projected to increase substantially in volume. Dual-Mobility (DM) implants, composed of articulating surface between femoral head and liner, have gained popularity for their potential to reduce hip instability and dislocations due to the larger DM femoral head options. This study aimed to evaluate early outcomes and survivorship of a novel DM implant for rTHA. Methods: This was a retrospective, multicenter study to assess clinical outcomes of 199 patients undergoing rTHA with a novel DM implant from April 2018 to July 2023. Patient demographics, clinical outcomes and implant survivorship were collected and analyzed. Primary outcomes included 90-day Emergency Department (ED) visits and readmissions, reoperations, revisions and overall implant survivability. Preoperative and postoperative Hip Disability and Osteoarthritis Score for Joint Replacement (HOOS, JR) were also analyzed. Results: 108 patients achieved minimum 1-year of clinical follow-up and 50 patients achieved minimum 2-years of clinical follow-up. Patients who received the novel DM implant were a mean of 67.3 years old, with the majority of the patients being women (58.0%) and of white race (68.0%). Mean BMI of patients was 29.5. Five patients (2.51%) had 90-day ED visits and readmissions due to dislocation (n = 3, 1.5%) and infection (n = 2, 1%). Two patients (1%) had revision of the acetabular component due to instability and one (0.5%) underwent close reduction a the dislocated rTHA. Patients experienced significant improvements in mean HOOS, JR scores at all postoperative time points, surpassing the minimally clinically important difference for HOOS, JR (18.0). Conclusion This novel DM acetabular implant demonstrated excellent survivorship of the acetabular component up to 4 years (99% [95% confidence interval (CI) 0.978 – 0.995], for both) of follow-up in complex rTHA cases, with low rates of instability and no reported episode of metallosis. Patients demonstrated clinically significant improvements in HOOS, JR at 2-years post-op.