HiL simulation in biomechanics: a new approach for testing total joint replacements

Area of Science:

• Biomechanics
• Medical Engineering
• Orthopedic Surgery

Background:

• Artificial joint instability is a major cause of revision surgery.
• Current testing methods lack physiologically realistic boundary conditions.
• Understanding instability mechanisms is crucial for improving implant longevity.

Purpose of the Study:

• To introduce a novel hardware-in-the-loop (HiL) simulation for investigating joint instability.
• To present the concept and implementation of a mechatronic test system for hip and knee replacements.
• To enable reproducible and physiologically realistic testing of implant stability.

Main Methods:

• A hardware-in-the-loop (HiL) simulation combining a physical setup (six-axes industrial robot) and a real-time numerical multibody model.
• The multibody model incorporates anatomical environment and soft tissue response.
• The robot manipulates real implant components based on the multibody model's output.

Main Results:

• The HiL joint simulator was successfully implemented and its control principles validated.
• The system accurately reproduced the dislocation process of a standard total hip replacement.
• The simulator demonstrated functionality for analyzing instability under realistic conditions.

Conclusions:

• The developed HiL simulation is a novel biomechanical testing tool for joint replacements.
• It allows for analysis of instability behavior under realistic movements and physiological loads.
• This approach facilitates comparable investigations of different total hip and knee replacement systems.