The Fragility of Statistical Findings in Cervical Disc Arthroplasty: a Systematic Review of Randomized Controlled Trials.

PURPOSE: This study employs both the fragility index (FI) and fragility quotient (FQ) to assess the level of robustness in the cervical disc arthroplasty (CDA) literature. We hypothesize that dichotomous outcomes involving CDA would exhibit statistical vulnerability. METHODS: A PubMed search was conducted to evaluate dichotomous data for randomized controlled trials (RCTs) in CDA literature from 2000 to 2023. The FI of each outcome was calculated through the reversal of a single outcome event until significance was reversed. The FQ was calculated by dividing each fragility index by the study sample size. The interquartile range (IQR) was also calculated for the FI and FQ. RESULTS: Of the 1561 articles screened, 111 met the search criteria, with 35 RCTs evaluating CDA included for analysis. Six hundred and ninety-three outcome events with 130 significant (P < 0.05) outcomes and 563 nonsignificant (P ≥ 0.05) outcomes were identified. The overall FI and FQ for all 693 outcomes were 5 (IQR 3-7) and 0.019 (IQR 0.011-0.043). Fragility analysis of statistically significant outcomes and nonsignificant outcomes both revealed an FI of 5. All of the studies reported loss to follow-up (LTF) data where 65.7% (23) did not report or reported an LTF greater or equal to 5. CONCLUSIONS: The literature regarding CDA RCTs lacks statistical robustness and may misrepresent the conclusions with the sole use of the P value. By implementing the FI and FQ along with the P value, we believe the interpretation and contextualization of the clinical data surrounding CDA will be better understood.

The Statistical Fragility of Orbital Fractures: A Systematic Review of Randomized Controlled Trials.

BACKGROUND: The P value has often been used as a tool to determine the statistical significance and evaluate the statistical robustness of study findings in orthopedic literature. The purpose of this study is to apply both the fragility index (FI) and the fragility quotient (FQ) to evaluate the degree of statistical fragility in orbital fracture literature. We hypothesized that the dichotomous outcomes within the orbital fracture literature will be vulnerable to a small number of outcome event reversals and will be statistically fragile. METHODS: Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), the authors identified all dichotomous data for randomized controlled trials (RCTs) in orbital fracture literature and performed a PubMed search from 2000 to 2022. The FI of each outcome was calculated through the reversal of a single outcome event until significance was reversed. The FQ was calculated by dividing each FI by study sample size. The interquartile range (IQR) was also calculated for the FI and FQ. RESULTS: Of the 3,329 studies screened, 28 met the criteria with 10 RCTs evaluating orbital fractures included for analysis. A total of 58 outcome events with 22 significant (P < .05) outcomes and 36 nonsignificant (P ≥ .05) outcomes were identified. The overall FI and FQ for all 58 outcomes was 5 (IQR: 4 to 5) and 0.140 (IQR: 0.075 to 0.250), respectively. Fragility analysis of statistical significant outcomes and nonsignificant outcomes had an FI of 3.5 with no IQR and 5 (IQR 4-5), respectively. All of the studies reported a loss to follow-up data, where 20% (2) was greater than the overall FI of 5. CONCLUSION: The orbital fracture literature provides treatment guidance by relying on statistical significant results from RCTs. However, the RCTs in the orbital fracture peer-reviewed literature may not be statistically stable as previously thought. The sole reliance of the P value may depict misleading results. Thus, we recommend standardizing the reporting of the P value, FI, and FQ in the orbital fracture literature to aid readers in reliably drawing conclusions based on fragility outcome measures impacting clinical decision-making.