High continuous fragility index values amongst trials comparing anterior cruciate ligament reconstruction with and...

This systematic review aimed to determine the statistical fragility of randomized controlled trials (RCTs) comparing anterior cruciate ligament reconstruction (ACLR) with or without anterolateral complex (ALC) procedures.

PubMed, MEDLINE, and EMBASE were searched from inception to April 22, 2024 for RCTs comparing ACLR with or without ALC procedures (lateral extra-articular tenodesis or anterolateral ligament reconstruction). Studies that reported ≥1 statistically significant continuous outcome, statistically significant dichotomous outcome, and/or non-significant dichotomous outcome were included. The fragility index (FI), continuous fragility index (CFI), and reverse fragility index (RFI) were calculated for these outcomes, respectively.

20 RCTs including 2,292 patients were included (mean study size: 114.6 patients). The median FI across 21 outcomes from 11 studies was 2.0 (interquartile range [IQR], 2.0). The median CFI across 20 outcomes from seven studies was 16.9 (IQR, 227.7). The median RFI across 107 outcomes from 19 studies was 5.0 (IQR, 2.0). The number of patients lost to follow-up at the final follow-up period was more than the study-specific FI in eight (72.7%) studies, CFI in two (28.6%) studies, and RFI in 12 (63.2%) studies.

This systematic review demonstrated that RCTs comparing ACLR with or without ALC procedures have low FI and RFI values that tended to exceed loss to follow-up, demonstrating relative statistical fragility of existing literature. However, CFI values were high amongst RCTs, suggesting robustness in findings for quantitative outcomes. While fragility indices are important metrics of robustness to consider, their application in research and clinical practice should be further investigated.