Mean distraction force applied in tension-controlled ligament-balanced total knee arthroplasty: A systematic review and meta-analysis.

PURPOSE: Proper tension of the collateral ligaments is the key to success in total knee arthroplasty (TKA). The study aimed to identify the distraction force for the medial and lateral femorotibial compartments in tension-controlled ligament-balanced TKA at 0° and 90° of knee flexion.

METHODS

A literature search was conducted in PubMed up to 31 December 2024 to identify studies that reported exact values of the distraction force applied in tension-controlled ligament-balanced TKA. Mean distraction force at 0° and 90° of knee flexion were calculated for the native knee, cadaver knee, and computer model/artificial knee groups. Differences between groups were calculated using Kruskal-Wallis and Mann-Whitney U tests, with p ≤ 0.05 considered significant. A frequentist meta-analysis of subgroup analysis between native and cadaver knee studies was performed using a random effects model with inverse variance and the Sidik-Jonkman heterogeneity estimator with Hartung-Knapp adjustment to calculate participant age and sex.

RESULTS

Out of 116 included primary studies involved, a total of 6869 participants had distraction force measurements during TKA. The mean distraction force was 149.9 N (35.0-320.0 N) at 0° knee extension and 139.5 N (14.7-244.7 N) at 90° of flexion. Using the Kruskal-Wallis test or the Mann-Whitney U test, there were no significant differences in distraction force between native knee, cadaver knee, computer model/artificial knee studies at extension (p = 0.2480 and p = 0.1130) and at 90° of knee flexion (p = 0.8439 and p = 0.6241).

CONCLUSION

This meta-analysis is the first to quantify distraction force in TKA, providing essential reference values of 149.9 N at 0° extension and 139.5 N at 90° flexion. These findings offer valuable guidelines for intraoperative soft tissue management during TKA procedures. The consistency of distraction force across different experimental models suggests that these values are broadly applicable. However, it remains unclear whether a more personalized distraction force should be considered for gap preparation.

LEVEL OF EVIDENCE: Level IV.