Dual mobility systems in revision of total hip replacement

Background: Dislocation remains a prevalent complication following revision total hip arthroplasty (rTHA), with reported incidence rates between 10% and 25%. Factors such as bone loss, abductor deficiency, and lumbopelvic kinematics contribute to construct instability, necessitating advanced implant strategies to restore hip function and stability.

Objective: This article evaluates the clinical utility, biomechanical principles, and outcomes of various acetabular components in rTHA, with a specific focus on the role of dual-mobility (DM) constructs in mitigating dislocation risk.

Key Points: Comparative data indicate that DM cups significantly reduce postoperative dislocation rates compared to large-diameter femoral heads or standard fixed-bearing implants. While large femoral heads increase jump distance, diameters exceeding 36 mm may paradoxically decrease stability by lateralizing the center of rotation. DM options include monoblock, modular, and cemented designs. Modular DM systems facilitate supplemental screw fixation but introduce potential risks of corrosion at the metal-on-metal interface and reduced jump distance. In cases of severe acetabular defects (Paprosky grade >2B), DM cups can be combined with reinforcement devices, such as Kerboull cross-plates or tantalum augments, or utilized within 3D-printed custom triflange implants. Long-term survival rates for DM constructs in complex revisions exceed 90% at 10 years. Constrained liners remain a secondary option for refractory instability but carry higher risks of impingement and mechanical failure.

Conclusion: Dual-mobility constructs provide a versatile and effective solution for reducing instability in rTHA. Successful outcomes depend on a precise preoperative assessment of bone stock and soft tissue integrity to select the appropriate monoblock, modular, or reinforced DM configuration.