Statistical fragility analysis of reported outcomes associated with surgical management of acetabular labral pathology.

Introduction: The purpose of this study was to analyse the robustness of comparative research that evaluated arthroscopic labral reconstruction versus other surgical management of labral pathology. Key measures of statistical fragility include the fragility index and fragility quotient.ß.

Methods: 12 comparative studies that evaluated the use of arthroscopic labral reconstruction were included in this study. Particular attention was placed on evaluating trends, either statistically significant or not, of functional improvement, complication rates, need for total hip arthroplasty (THA) and revision rates with associated p-values. The analysis involved in this study was the Fragility Index, which is the median number of events required to change the statistical significance of a particular outcome, thus changing the study conclusions. Fragility quotient was calculated for each study as the fragility index divided by sample size.

Results: Of the 12 studies that were included for analysis, there were a total of 25 reported outcomes, 8 of which were statistically significant (p < 0.05). The statistical fragility for the significant outcomes were 2.5 (interquartile range [IQR]: 1.5-3.5), whereas the median statistical fragility for insignificant results was 6 (IQR 4-9). The overall fragility index was 4 (IQR 3-7). The median of fragility quotients was 0.04 (IQR 0.01-0.07).

Conclusions: This study demonstrated that comparative research regarding arthroscopic techniques of labral reconstruction may not be as statistically stable as previously hoped. In many of the reported outcomes, particularly the ones that were statistically significant, only a small percentage of event changes was required to change the significance of the study conclusions. This fragility is worrisome, since clinical decisions that rely on these reported outcomes may have a significant impact on long-term patient outcomes. It is, therefore, crucial to optimise patient outcomes by incorporating past literature and reported outcomes.