Numerical Simulation of Electric Field Distribution around an Instrumented Total Hip Stem

Abstract

Presently, total joint replacement (TJR) is a standard procedure in orthopedic surgery. Adequate osseointegration of the implant components still remains a clinical issue. However, active stimulation of bone tissue to enhance bone ongrowth at the implant surfaces has not been widely investigated so far. For the last several years, invasive electromagnetically induced osseotherapy has been employed in clinical practice, e.g., for the treatment of avascular necrosis, femoral neck fractures, and pseudarthrosis. In the present study, the approach of exploiting the electric stimulation effect was transferred to the field of TJR. Therefore, a commercially available total hip stem was instrumented with an electrode on its surface in order to generate an electric field supporting the regeneration of the surrounding bone tissue. The objective was to conduct numerical simulations validated by experimental investigations as a proof of concept for an instrumented electro-stimulative total hip stem. The results revealed that the calculated electric field around a total hip stem fulfills the requirements to stimulate adjacent bone tissue when using clinically applied electric voltages. The derived numerical and experimental data of electric potentials and corresponding electric fields are encouraging for the implementation of active electrical stimulation in uncemented total hip stems to enhance their osseointegration.

Keywords

• electrical stimulation
• numerical simulation
• electric field distribution
• experimental validation
• osseointegration
• total hip replacement (THR)