# The risk of revision using tourniquet or not in primary total knee replacement: an observational study from the Swedish Knee Arthroplasty Register

## TL;DR

A study of over 149,000 knee replacements found that using a tourniquet during surgery may increase the risk of implant loosening after five years, but not overall revision or infection rates.

## Contribution

This observational study provides new evidence on the long-term risks of tourniquet use in knee replacement surgery, specifically for implant loosening.

## Key findings

- Tourniquet use was linked to a higher risk of revision for implant loosening after five years (HR 1.56).
- No significant association was found between tourniquet use and all-cause revision or infection rates.
- Cumulative revision rates for implant loosening began to diverge at 6–7 years in tourniquet cases.

## Abstract

The use of a tourniquet in knee replacement surgery is debated. Given the conflicting evidence, we aimed to compare the risk of revision after total knee replacements (TKR) with or without the use of tourniquet.

In this register based observational study, we included the 5 most common cemented primary TKR models due to osteoarthritis reported to the Swedish Arthroplasty Register 2010–2024 and followed them until December 31, 2024. The first revision for implant loosening was the primary outcome. We estimated the cumulative revision rate (CRR) with 95% confidence interval (CI) using the 1–Kaplan–Meier method. We examined the use of a tourniquet regarding the risk of revision using multiple Cox regression analysis to calculate the hazard ratio (HR) with CI and adjusted for potential confounding factors.

Of the 149,616 TKRs included, 65,570 (44%) were with tourniquet and 84,046 (56%) without tourniquet. The CRR was similar at all time-points for all causes and infection; however, CRR started to increase at 6–7 years for implant loosening with use of a tourniquet. In the Cox regression analysis, the use of a. tourniquet was associated with an increased risk of revision for implant loosening after 5 years (HR 1.56, CI 1.06–2.30). There was no difference in revision for all causes (HR 1.07, CI 0.99–1.15) or infection (HR 1.08, CI 0.97–1.21).

The use of a tourniquet was associated with an increased risk of revision for implant loosening after 5 years, while no association was found for all-cause revision or infection. Our results do not support the use of a tourniquet in TKR as a strategy to reduce the risk of revision, either due to all causes, implant loosening, or infection.