# Robotic total knee arthroplasty with functional positioning safely addresses major coronal deformities: Comparable complications and survivorship

## TL;DR

Robotic-assisted knee replacement surgery works safely for patients with major leg deformities, offering similar outcomes to standard cases.

## Contribution

The study demonstrates the feasibility of robotic TKA for severe deformities with comparable complication and revision rates.

## Key findings

- Patients with deformities had similar complication and revision rates as controls.
- Functional outcomes were better in the deformity group, though not clinically significant.
- Postoperative alignment was less neutral in the deformity group but did not affect implant survival.

## Abstract

Robotic‐assisted total knee arthroplasty (TKA) has emerged as a reliable strategy to improve surgical accuracy and enable functional alignment (FA), also referred to as functional knee positioning (FKP). However, its application in patients with major coronal plane deformities remains under‐investigated. This study aimed to evaluate complication rates, implant survival, radiographic outcomes and patient‐reported measures in patients with severe deformities undergoing robotic‐assisted TKA with FA/FKP principles compared to matched controls.

A retrospective comparative study was conducted on patients who underwent robotic‐assisted TKA between March 2021 and February 2023 at a single high‐volume centre. Patients with ≥15° varus or ≥10° valgus deformity were included in the study group and matched 1:1 with controls presenting neutral alignment. All procedures used the Mako robotic‐arm‐assisted system with standardised FA/FKP principles. Clinical outcomes included knee society score (KSS), forgotten joint score (FJS‐12), Kujala anterior knee pain scale (AKPS) and range of motion. Radiographic measurements and robotic data were assessed. Complications, reoperations and revision rates were analysed.

Eighty‐eight patients (44 per group) were analysed, with a mean follow‐up of 2.8 ± 0.9 years. Complication and revision rates were comparable between groups (revision: 2.3% vs. 0%, p = 0.987). Patients with major deformities achieved higher FJS‐12 scores (83.9 ± 20.2 vs. 74.9 ± 19.0, p = 0.040), although the difference did not exceed the minimal clinically important difference (MCID = 9.9). Postoperative mHKA was less neutral in the deformity group (176.8° ± 4.7 vs. 180.0° ± 3.0, p = 0.002), without adverse impact on implant survival.

Robotic‐assisted TKA performed with FA/FKP principles appears to be a feasible option for patients with severe varus or valgus deformities. Despite residual alignment variability, complication and revision rates remained comparable to standard cases, and patient‐reported outcomes suggested greater perceived functional improvement.

Level III.

Robotic‐assisted TKA performed with functional knee positioning shows comparable short‐term safety and functional outcomes in patients with major coronal deformities.