The Fragility of Statistical Findings in the Femoral Neck Fracture Literature: A Systematic Review of Randomized Controlled Trials

Abstract

Objectives: Randomized controlled trials (RCTs) in the femoral neck fracture literature frequently report p-values for outcomes which have substantial implications in guiding surgical management. This study utilized the fragility index (FI), reverse fragility index (rFI), and fragility quotient (FQ) to assess the statistical stability of outcomes reported in RCTs evaluating the management and treatment of femoral neck fractures. Methods: Data Sources: Pubmed, Emabse, and MEDLINE were queried for RCTs (January 1, 2010 to February 28th, 2023) that evaluated surgical management/treatment of femoral neck fractures. Study Selection: RCTs with two treatment arms reporting categorical dichotomous outcomes were included. Non-RCT studies, RCTs with greater than 2 treatment arms, and RCTs without a femoral neck fracture cohort were excluded. Data Extraction and Synthesis: The FI and rFI were calculated as the number of outcome event reversals required to alter statistical significance for significant (p<0.05) and non-significant (p≥0.05) outcomes, respectively. The FQ was calculated by dividing the FI by the sample size for the study. Results: 985 articles were screened with 71 studies included for analysis. The median FI across a total of 197 outcomes was 4 (IQR 2-5) with an associated FQ of 0.033 (IQR 0.017-0.060). 47 outcomes were statistically significant with a median FI of 2 (IQR 1-4) and associated FQ of 0.02 (IQR 0.014-0.043). 150 outcomes were statistically non-significant with a median rFI of 4 (IQR 3-5) and associated FQ of 0.037 (IQR 0.019-0.065). Conclusion: Statistical findings in femoral neck fracture RCTs are fragile with reversal of a median 4 outcomes altering significance of study findings. The authors thus recommend standardized reporting of p-values with FI and FQ metrics to aid in interpreting the robustness of outcomes in femoral neck fracture RCTs. Level of evidence: Level I. See Instructions for Authors for a complete description of levels of evidence.