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

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Journal of Orthopaedic Trauma


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 used 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:Design:PubMed, Embase, and MEDLINE were queried for RCTs (January 1, 2010 to February 28, 2023).Setting:RCTs that evaluated surgical management or treatment of femoral neck fractures were included.Study Selection Criteria:RCTs with 2 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:Outcome Measures and Comparisons:The FI and rFI were calculated as the number of outcome event reversals required to alter statistical significance for significant (P < 0.05) and nonsignificant (P ≥ 0.05) outcomes, respectively. The FQ was calculated by dividing the FI by the sample size for the study.RESULTS:Nine hundred eighty-five articles were screened, with 71 studies included for analysis. The median FI across a total of 197 outcomes was 4 [interquartile range (IQR) 2-5] with an associated FQ of 0.033 (IQR 0.017-0.060). Forty-seven outcomes were statistically significant with a median FI of 2 (IQR 1-4) and associated FQ of 0.02 (IQR 0.014-0.043). One hundred fifty outcomes were statistically nonsignificant with a median rFI of 4 (IQR 3-5) and associated FQ of 0.037 (IQR 0.019-0.065).CONCLUSIONS: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:Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

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