Estimation of change of bone structures after total hip replacement using bone remodeling simulation

Area of Science:

• Biomedical Engineering
• Orthopedic Surgery
• Computational Mechanics

Background:

• Femoral stem failure in total hip replacement is often caused by loosening due to stress shielding, a process where bone resorbs near the prosthesis.
• Surgical interventions like hip replacement significantly alter the mechanical environment of the bone.

Purpose of the Study:

• To develop and validate a computational method for predicting bone structure changes after total hip replacement.
• To assess the impact of stress shielding on bone remodeling and prosthesis longevity.

Main Methods:

• A bone-stem complex model was created from CT images for preoperative planning.
• Bone remodeling simulation was performed under daily loading conditions using a validated remodeling model.
• Equivalent stresses in the Gruen zones were evaluated to assess bone remodeling.

Main Results:

• Predicted bone loss due to stress shielding correlated with clinical follow-up data.
• The simulation identified size-dependent stress changes in the Gruen zone based on implant size.
• Significant stress changes and bone loss were observed under the stem neck, indicating risks of loosening or fracture.

Conclusions:

• Predicting bone structure changes provides crucial information for enhancing prosthesis longevity.
• The developed computational framework shows potential for improving preoperative planning in total hip replacement surgeries.