# Image‐based robotics enhance precision and efficiency in lateral UKA: A comparative study of 135 UKAs

## TL;DR

This study compares image-based and imageless robotic systems in lateral knee surgery, finding that image-based systems offer better accuracy and faster surgery.

## Contribution

The paper provides the first direct comparison of image-based and imageless robotic systems in lateral unicompartmental knee arthroplasty.

## Key findings

- Image-based robotics achieved higher accuracy in hip–knee–ankle alignment and joint line restoration.
- Image-based systems had significantly shorter operative times compared to imageless systems.
- Posterior tibial slope accuracy was similar between the two robotic systems.

## Abstract

Robotic‐assisted lateral unicompartmental knee arthroplasty (UKA) remains technically demanding due to the complex biomechanics of the lateral compartment. Image‐based (IBRA) and imageless (ILRA) robotic systems have both demonstrated superior accuracy compared to conventional mechanical instrumentation, but have not yet been directly compared in lateral UKA. This study aimed to evaluate their respective accuracy and surgical efficiency.

This retrospective study included 135 patients who underwent lateral UKA using either IBRA or ILRA systems. Post‐operative radiographic outcomes included hip–knee–ankle (HKA) alignment, posterior tibial slope (PTS) and joint line (JL) restoration. Surgical time was assessed as a secondary outcome. Target zones were HKA 180°–185°, PTS 2°–8° and JL ± 2 mm.

IBRA showed higher rates of HKA inliers (94.9% vs. 78.9%, p = 0.011) and JL restoration (76.2% vs. 31.6%, p < 0.001) compared to ILRA. PTS accuracy was similar between groups (p = 0.30). Operative time was significantly shorter with IBRA (61.6 ± 13.5 vs. 81.9 ± 26.1 min, p < 0.001).

IBRA outperformed ILRA in terms of alignment accuracy and surgical duration. These findings support the added value of IBRA systems in lateral UKA.

Level IV, retrospective case series study.