# Numerical Simulation of the Effect of Electrical Stimulation on Disuse After Hip Replacement

## TL;DR

This paper uses simulations to show that electrical stimulation can help prevent bone loss in the femur after hip replacement surgery.

## Contribution

A new disuse remodeling model was developed to simulate the resistance effect of electrical stimulation on bone density loss.

## Key findings

- Hip replacement causes stress masking and significant density loss in the femur neck.
- Electrical stimulation in the femur neck can reduce bone mineral density loss.
- The model shows electrical stimulation helps counteract density reduction from stress shielding.

## Abstract

Background: Total hip replacement replaces the femoral head, which cannot heal, with an artificial femoral shaft to ensure the patient’s normal life. However, due to the stress-masking effect of the proximal femur loaded with the artificial femur stem, the implant bears a large part of the load, resulting in insufficient stress stimulation of the proximal femur and bone waste remodeling. In turn, it is easy to lose bone, resulting in loosening. As a new treatment method, electrical stimulation has been widely used for bone loss, nonunion, and other diseases, and it has achieved good therapeutic effects. Methods: Therefore, in this work, electrical stimulation was introduced for postoperative density assessment, and a new disuse remodeling model was established to simulate density loss after remodeling and the resistance effect of electrical stimulation. The effects of various parameters on density loss in the model are discussed. Results: The simulation results revealed significant stress masking and density loss in the neck of the femur after hip replacement, and electrical stimulation placed in the neck of the femur may resist this density loss to a certain extent. The rate of bone mineral density reduction decreased after the addition of electrical stimulation, indicating that electrical stimulation can have a certain resistance to the density reduction caused by stress shielding, and this result is helpful for the rehabilitation of hip arthroplasty.