Poster 346: The Statistical Fragility of Lateral Extra-articular Tenodesis Research: A Systematic Review
Authors: Quinn Matthew , Ahn Benjamin , Byrne Rory , Zhao Leon , Naphade Om , Owens Brett 
Published: August 2024

Objectives: With reinterest in lateral extra-articular tenodesis (LET), there is an imperative need to evaluate the rigor of clinical studies regarding LET with anterior cruciate ligament reconstruction (ACLR). This study aims to present a comprehensive picture of the robustness of evidence from comparative studies regarding LET and to inform evidence-based medical decision-making for current practitioners. We hypothesized that the results of these analyses will show statistical fragility, consistent with similar evidence across the orthopaedic literature. Methods: Using the PubMed database, comparative studies and randomized controlled trials (RCTs) related to LET as an augmentation procedure to ACLR or revision ACLR published between 2000 and 2022 were identified and collected. Studies on the topic were broadly queried for relevance, and after screening, they were included if they were (1) pertaining to LET as an augmentation to ACLR or revision ACLR, and (2) designed as comparative studies or RCTs. Exclusion criteria included (1) cadaveric, nonhuman, in vitro, laboratory, or surgical technique (without patient outcomes); (2) commentary, editorial, letter to the editor, conference reports, future study design/published protocol; (3) only abstract available; (4) non-English; or (5) lacked the statistical basis for a fragility analysis. Manuscripts were independently reviewed by three authors and variables of interest of interest were extracted, including both dichotomous and continuous variables relevant to clinical decision making. Discrepancies were resolved via paired discussions. For each dichotomous outcome, we calculated a Fragility Index (FI). FI was calculated using a 2-by-2 contingency table and the Fisher's exact test using the method outlined in Figure 1. For each continuous outcome, we calculated a Continuous Fragility Index (CFI). CFI was calculated using Welch's t-test and the method proposed by Caldwell et al to expand fragility analysis to continuous variables. The analysis for each outcome was conducted with n = 5 simulations using synthetic, representative data generated from the reported sample mean, standard deviation, and sample size for both the experimental and control arms. For both dichotomous and continuous outcomes, the statistical fragility was reported using median and interquartile range. Comparisons of mean statistical fragility were conducted using a nonparametric t test. Data were analyzed using Python 3.7. Results: Out of the 455 initially identified studies, 178 full texts were screened. Ultimately, 29 studies were included in the final analysis, including 20 comparative studies and 9 RCTs. 18 studies reported dichotomous outcomes and 27 studies reported continuous outcomes, which resulted in a cumulative total of 48 dichotomous outcomes and 265 continuous outcomes for analysis. Figure 4 reports the distribution of FI and CFI values for all dichotomous and continuous outcomes. The median FI was 9.0 (25-75th percentile, 7.0-13.25). The median CFI was 7.8 (25-75th percentile, 4.2-19.6). Commonly reported dichotomous outcomes included clinical failure, graft rupture, and return to sport. The number of outcomes in which loss to follow-up (LTF) exceeded the FI was 13 (27%). Reported significant dichotomous outcomes were significantly more fragile than outcomes that were not significant (fragility quotient [FQ] = 0.02 vs 0.11, Welch t test p < 0.001); however, most dichotomous outcomes were reported insignificant (79.2%) (Table 1). Commonly reported continuous outcomes across different studies included KOOS, IKDC, and Lysholm scores. LTF exceeded the CFI for 20 outcomes (8%). In contrast to dichotomous outcomes, continuous outcomes from RCTs and comparative studies were equivalently robust (continuous fragility quotient [CFQ] = 0.12 vs 0.12). The CFQ of both significant and nonsignificant continuous outcomes were similarly equal (0.12 vs 0.12) (Table 2). Reports on fragility quotients from studies that focused on LET for either primary or revision ACLR clinically are presented in Table 3. These subgroups excluded translational research and imaging studies. The FQ and CFQ for studies focused on revision ACLR were larger (0.117 and 0.113) than those focused on primary ACLR (0.042 and 0.095). Conclusions: Research regarding the usage of LET as an augmentation procedure for ACLR and revision ACLR is more statistically robust than many other topics within orthopaedics. Studies regarding LET with primary ACLR are more fragile than those for revision ACLR. Given the resurgent interest in this procedure and the current mixed evidence regarding its effectiveness and indications, we recommend the future reporting of fragility quotients alongside p-values, to assist clinicians in assessing the robustness of new evidence to inform decision making.