Randomized trials evaluating volar locking plates against casting of distal radius fractures are statistically fragile: A systematic review

Introduction: Despite randomized controlled trials (RCTs) largely supporting volar locking plates (VLPs) for the management of distal radius fractures (DRFs), surgeons often opt for non-invasive interventions such as casting. This study used the fragility index (FI), reverse fragility index (rFI), and fragility quotient (FQ) to assess the statistical robustness of RCTs assessing the efficacy of VLP in DRF management. Methods: PubMed, Embase, and MEDLINE were queried for RCTs evaluating VLP versus casting for DRFs published from January 1st, 2000-June 30, 2024. FI and rFI were quantified for all dichotomous outcomes, and represent the number of event reversals required to alter statistical significance or non-significance, respectively. The FQ was then determined by dividing the FI or rFI by the sample size. A subanalysis was performed for outcomes pertaining to patient satisfaction, healing/function, and adverse events. Results: A total of 699 RCTs were identified in the initial literature search. 13 RCTs were eventually included in the final analysis, yielding 36 dichotomous outcomes. The median FI across these outcomes was 3 (IQR 3-5) and the median FQ was 0.037 (IQR 0.014-0.067). Among the 15 significant outcomes, the median FI was 2 (IQR 2-4) and the median FQ was 0.029 (IQR 0.013-0.055). The remaining 21 non-significant outcomes yielded a median rFI of 4 (IQR 2-5) and a median FQ of 0.042 (IQR 0.021-0.091). The most statistically fragile outcome category was patient satisfaction, with a median FI of 2 (IQR 2-3.5) and median FQ of 0.016 (IQR 0.013-0.030). Among 21 of the included outcomes (58.3 %), the number of patients lost to follow up exceeded the respective FI or rFI. Conclusion: A statistical fragility analysis of VLP versus casting for DRFs demonstrated fragile outcomes, reporting a median FQ of 0.037, or 3.7 %. Statistically significant outcomes and patient satisfaction results were particularly fragile, and large losses to follow up were found to be an important contributor to RCT fragility. Although VLP is largely recommended by level I evidence, its superiority may not be as ubiquitous as argued by contemporary literature.