Statistical Fragility of Surgical and Procedural Clinical Trials in Orthopaedic Oncology

The fragility index (FI) is a powerful tool that can be used to assess the statistical strength of a study outcome. This metric is defined as the number of patients who would need to have an alternative outcome to convert a clinical trial result from statistically significant to not statistically significant, or vice versa. No studies to date have used the FI to evaluate surgical and procedural clinical trials in the orthopaedic oncology literature. The primary purpose of this study was to use the FI to evaluate the statistical strength of widely cited surgical and procedural clinical trials in orthopaedic oncology.

We performed a PubMed search for orthopaedic oncology clinical trials in high impact orthopaedics-focused, oncology-focused, and general medicine journals. For each study included in this analysis, we calculated the FI for all identified dichotomous, categorical outcomes.

We identified 23 studies with 48 outcomes. Twelve of these outcomes were statistically significant, with a median FI of two. Nine studies addressed the number of patients lost to follow up, and the FI was less than the number of patients lost to follow up for most outcomes (60%) in these studies.

The orthopaedic oncology literature has substantial statistical fragility, likely explained by a high number of patients lost to follow up and small sample sizes. More multicenter, cooperative studies are necessary to increases the robustness of clinical research in orthopaedic oncology.