# Component orientation measurements in total hip arthroplasty using an inertial measurement unit-based smart trial system

## TL;DR

This study introduces a new system for measuring hip implant orientation during surgery that is accurate and easier to use than existing methods.

## Contribution

A novel IMU-based system for intraoperative hip component orientation measurement with validated accuracy and practicality.

## Key findings

- The IMUHST system showed accuracy and precision suitable for clinical use.
- The system eliminates the cost and complexity of optical navigation systems.
- Validation was performed using a 3D measurement model as a reference standard.

## Abstract

Intraoperative measurement of component orientation represents a basis for optimizing outcomes after total hip arthroplasty (THA). Although the use of computer navigation systems in THA has improved the accuracy of component positioning, they have not gained widespread popularity due to their complexity, time demands, and time-consuming protocols.

We developed an Inertial Measurement Unit-based Hip Smart Trial system (IMUHST) to assist with intra-operative monitoring of hip posture. An in vitro validation experiment was conducted using a sawbones with a three-dimensional (3D) measurement model as the reference standard.

The absolute mean error, Bland–Altman analysis, and Intra-class Correlation Coefficient revealed that the accuracy and precision of this system meet the threshold for clinical application.

In conclusion, this in vitro validation demonstrates that the IMUHST system provides accurate component orientation measurements while eliminating the cost and complexity of optical navigation, offering a practical solution for widespread adoption.

Video Abstract

Video Abstract

The online version contains supplementary material available at 10.1186/s42836-025-00312-3.