Component Loosening in Total Hip Arthroplasty

Abstract

Aseptic loosening in total hip arthroplasty remains a significant barrier to long-term implant survival. Improvements in surgical technique, designs, and biomaterials over the past three decades have improved loosening rates from an initial 30 to 40% at 10 years to present rates of 3% (femur) and less than 5% (acetabulum) at 10 years. Refinement of cement technique has made noted improvements in survivability of femoral cemented stems but little difference in cemented acetabular components. Long-term outcome of well-cemented femoral stems has been an established benchmark, but is rivaled, and in some cases surpassed, by the success of cementless designs in fixation. Recognition of circumstances that may accelerate the wear process, thus facilitating progressive lysis and eventual loosening, requires a keen consideration of materials, implant orientation, patient activity, and adequate clinical observation. Radiolucency is variable and provides evidence of potential loosening. Pain in the groin region or anterior thigh aggravated with weight bearing remains the most reliable clinical indicator. Change in component position or apparent migration from one consistent radiographic study to another signifies definitive evidence of loosening.