# Intraoperative robotic measurements of coronal alignment in total knee arthroplasty correlate with pre‐ and post‐operative long‐leg radiographs

## TL;DR

This study shows that robotic measurements during knee replacement surgery are accurate and reliable when compared to traditional X-ray methods.

## Contribution

The study validates the accuracy of intraoperative robotic measurements for knee alignment against long-leg radiographs.

## Key findings

- Robotic measurements correlated highly with preoperative X-rays (Pearson r² = 0.68).
- There was no significant difference in femoral and tibial alignment between robotic and X-ray methods.
- The mean difference in femoral and tibial alignment was 0.43° and 0.01°, respectively.

## Abstract

This study sought to validate intraoperative robotic measurements of femoral and tibial component coronal alignment in total knee arthroplasty (TKA) by comparing to pre‐ and post‐operative standing, double stance, long‐leg radiographs (LLR).

This retrospective cohort study included 59 unique patients undergoing primary TKA at a single institution. Pre‐ and post‐operative femoral and tibial coronal alignment were measured on LLRs using a deep learning artificial intelligence model and compared to measurements obtained from the imageless robotic system to evaluate the robot's accuracy and reliability.

Robotic measurements were highly correlated with measurements from preoperative LLR (Pearson r
2 = 0.68). There was no significant difference in preoperative constitutional alignment between the two methodologies (p = 0.28). Additionally, the intraoperative and post‐operative alignment of femoral and tibial implants were not significantly different (p = 0.12 and p = 0.95, respectively) and were strongly correlated (Pearson r
2 = 0.5 and Pearson r
2 = 0.6 respectively). The mean difference in femoral alignment was 0.43° and the mean difference in tibial alignment was 0.01°.

The findings of this study suggest that there were no significant differences in the coronal alignment of TKA when assessed by a robotic system compared to LLR. This signifies the robotic system's high intraoperative accuracy and reliability in determining coronal alignment.

Level III.