Comparative Studies in the Shoulder Literature Lack Statistical Robustness: A Fragility Analysis

Area of Science:

• Orthopaedic Surgery
• Biostatistics
• Clinical Research Methodology

Background:

• Evidence-based decision-making relies on comparative clinical studies.
• A small number of outcome reversals can significantly impact study conclusions.
• Fragility analysis assesses the statistical robustness of study findings.

Purpose of the Study:

• To evaluate the utility of fragility analysis in comparative orthopaedic shoulder studies.
• To determine the statistical fragility of published shoulder research.

Main Methods:

• Analysis of comparative clinical shoulder studies (1:1 dichotomous data) from 2006-2016 in 6 leading journals.
• Calculation of fragility index (FI) and fragility quotient (FQ) for study outcomes.
• Statistical significance defined as P < 0.05.

Main Results:

• 198 comparative studies were analyzed; 67 were randomized controlled trials.
• The median FI was 4 (IQR 2-6) and the median FQ was 0.066 (IQR 0.038-0.102).
• No significant difference in statistical fragility was found between randomized and non-randomized trials.

Conclusions:

• Comparative shoulder studies in leading orthopaedic journals exhibit statistical fragility.
• The P-value alone may be insufficient for interpreting study significance.
• Reporting FI and FQ alongside P-values is recommended for a comprehensive understanding of trial stability.