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The Reverse Continuous Fragility Index of Randomized Controlled Trials Comparing Capsular Closure Versus Noncapsular
Eric Y Hu1, Thomas E Moran1, Jesus E Cervantes1
1Section of Young Adult Hip Surgery, Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center, Chicago, Illinois, USA.
The reverse continuous fragility index (rCFI) indicates that nonsignificant results in hip arthroscopy studies comparing capsular closure are robust. Larger sample sizes in randomized controlled trials (RCTs) are linked to more reliable nonsignificant findings.
Area of Science:
- Orthopedic Surgery
- Biostatistics
- Clinical Trial Methodology
Background:
- The traditional P value in randomized controlled trials (RCTs) has limitations in categorical interpretation.
- The reverse continuous fragility index (rCFI) extends fragility metrics to continuous, nonsignificant outcomes.
- This study focuses on rCFI for capsular closure versus nonclosure in hip arthroscopy.
Purpose of the Study:
- To characterize the rCFI of statistically nonsignificant results in RCTs comparing capsular closure and nonclosure for femoroacetabular impingement (FAI).
- Hypothesized that nonsignificant differences would be robust (rCFI > loss to follow-up rate).
- Hypothesized that rCFI would exceed traditional fragility index (FI) and continuous FI (CFI) values in sports medicine literature.
Main Methods:
- A meta-analysis of RCTs comparing hip arthroscopic capsular closure vs. nonclosure was conducted.
- Searched PubMed, Cochrane, and Embase databases for relevant studies up to October 2024.
- Calculated mean rCFI for primary nonsignificant outcomes and used multivariate regression to identify predictors of high rCFI.
Main Results:
- Six studies with 416 patients were analyzed, identifying 136 nonsignificant outcomes.
- The mean rCFI was 16.333 (SD, 6.121), exceeding the mean loss to follow-up rate of 11.03% (SD, 5.79%).
- Multivariate regression revealed that sample size significantly predicted higher rCFI (P = .018).
Conclusions:
- Nonsignificant differences in hip arthroscopy RCTs comparing capsular closure vs. nonclosure appear relatively robust.
- Increased sample sizes in RCTs are associated with greater robustness of nonsignificant findings.
- rCFI provides a valuable metric for assessing the reliability of nonsignificant outcomes in orthopedic research.