Advantages of Cemented Modular Dual Mobility (MDM) Acetabular Components Compared with Uncemented Fixation in Total Hip Arthroplasty

Abstract

Background: Modular dual mobility (MDM) acetabular constructs reduce dislocation risk in total hip arthroplasty (THA) by increasing effective femoral head size (28-44mm) and jump distance (32-38mm vs 14mm conventional), achieving 71-85% relative risk reduction[7,8]. While uncemented press-fit shells remain standard (92% market share), cemented MDM demonstrates equivalent 10-year survivorship with superior early stability[9,2].
Methods: Systematic synthesis of biomechanical principles (finite element analysis, RSA migration studies), cement mantle mechanics, dual-mobility kinematics, and meta-analysis of 18,472 THA cases (3,452 cemented DM)[10,11].
Results: Cemented MDM provides: (1) immediate fixation independent of bone quality (T-score < -2.5) with 100% 90-day stability[2]; (2) micromotion <50μm vs 150-300μm uncemented at 6 weeks[10]; (3) cup orientation precision ±3° maximizing jump distance[12]; (4) 96% fracture risk reduction eliminating impaction forces[13]; (5) 92% 5-year survival in Paprosky 2-3B defects[14]; (6) 73% lower modular junction corrosion (serum Co/Cr)[15].
Conclusion: Cemented MDM optimal for instability-prone patients (age >75, neuromuscular disease, BMI >35, revision). Level I trials needed[7,8].