# Comparative analysis of revision causes between robotic-assisted and conventional manual unicompartmental knee arthroplasty: a systematic review and meta-analysis

## TL;DR

This study compares robotic-assisted and conventional unicompartmental knee arthroplasty to determine which has lower revision rates and reasons for failure.

## Contribution

The paper provides a systematic review and meta-analysis comparing revision causes between robotic-assisted and conventional unicompartmental knee arthroplasty.

## Key findings

- Conventional unicompartmental knee arthroplasty had higher total revision rates compared to robotic-assisted.
- Loosening was the main cause of revision in both groups, but robotic-assisted showed lower risk for loosening and disease progression.
- Limb malalignment was a major cause for conventional procedures, while pain was more common in robotic-assisted revisions.

## Abstract

Robotic-assisted unicompartmental knee arthroplasty (R-UKA) is an emerging procedure; however, its benefits over conventional manual unicompartmental knee arthroplasty (C-UKA) are controversial, especially the revision and failure rates, and existing studies failed to reach a consensus on this issue.

The literature search was conducted on four databases (PubMed, Embase, Cochrane Library and Web of Science) from inception to 28 April 2025 according to the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Eligibility criteria were studies that were written in English and reported any causes for a revision or failure subsequent to UKA with comparisons between R-UKA and C-UKA. The quality of each article was assessed using the Cochrane collaboration risk of bias tool or the Newcastle–Ottawa Scale.

A total of 15 studies incorporating 29,982 patients with 30,099 knees (22,290 in the C-UKA group and 7809 in the R-UKA group) were analyzed. Compared with R-UKA, C-UKA showed higher total revision rates (RR: 1.58; 95% CI: ~1.33–1.87; P < 0.00001; I2 = 43%). Prosthesis loosening, infection, pain, and progression of disease were the main reasons for R-UKA revision, whereas for C-UKA revision, loosening, progression of disease, infection, and limb malalignment were the major causes. Loosening was the predominant reason in both groups across all follow-up periods; early revisions were also due to infection and disease progression. Within 2–5 years, the secondary reasons differed, being limb malalignment for C-UKA and pain for R-UKA.

Compared with C-UKA, R-UKA may lower the risk of revision related to loosening, disease progression, and limb malalignment. Loosening remains the primary revision cause for both. Large-scale prospective trials with unified technical details are warranted to draw more rigorous conclusions in the future.

PROSPERO CRD420251042604.

The online version contains supplementary material available at 10.1186/s43019-026-00311-x.