Cuadros Adriano, Corvi Michaela, Yendluri Avanish, Docters Francesca, Shatkin Michael S, Corvi John J, Dhanjani Suraj A, Hayden Brett L, Unis Douglas B, Parisien Robert L
Department of Orthopedic Surgery, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Pl, New York, NY, USA.
Department of Orthopedic Surgery, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin, Ireland.
J Orthop. 2025 May 10;65:204-210. doi: 10.1016/j.jor.2025.05.016. eCollection 2025 Jul.
Randomized controlled trials (RCTs) that assess kinematic alignment (KA) versus mechanical alignment (MA) in total knee arthroplasty (TKA) report p-values that influence surgical decision-making. This study utilizes fragility index (FI) and fragility quotient (FQ) metrics to assess the statistical stability of outcomes reported in RCTs comparing KA and MA approaches in TKA.
Pubmed, Embase, and MEDLINE were queried for RCTs evaluating KA vs MA approaches in TKA. The FI and reverse fragility index (rFI) were calculated for dichotomous outcomes and were defined as the number of event reversals needed to alter the statistical significance for significant and non-significant outcomes, respectively. The continuous fragility index (cFI) was used to evaluate statistically significant continuous variables and was calculated using a novel online tool. The FQ was calculated by dividing the FI, rFI, or cFI by sample size.
The median FI across 58 included outcomes was 7.0 (FQ 0.109). Overall, dichotomous variables were more fragile than continuous variables. The 12 dichotomous outcomes were all statistically non-significant, with a median rFI of 4.5 (FQ 0.040). The 46 continuous outcomes were all statistically significant, with a median cFI of 9.1 (FQ 0.113). In 21 of 58 outcomes, the number of patients lost to follow up was greater than the FI for the respective outcome. When analyzing by outcome category, clinical improvement and complications were more fragile, with median FIs of 6.7 and 5.0.
Continuous outcomes were more robust than the relatively fragile dichotomous outcomes. The continuous outcomes in KA versus MA RCTs were also more robust compared to other current studies reporting cFI values. cFI is a novel, valuable tool that allows for assessment of fragility for continuous outcomes, and reporting alongside FI, rFI, and FQ with p-values is recommended to assess the reliability of RCTs.
评估全膝关节置换术（TKA）中运动学对线（KA）与机械学对线（MA）的随机对照试验（RCT）报告的p值会影响手术决策。本研究利用脆弱性指数（FI）和脆弱性商数（FQ）指标来评估比较TKA中KA和MA方法的RCT报告结果的统计稳定性。
在Pubmed、Embase和MEDLINE中查询评估TKA中KA与MA方法的RCT。为二分结果计算FI和反向脆弱性指数（rFI），分别定义为改变显著和非显著结果的统计显著性所需的事件反转数。连续脆弱性指数（cFI）用于评估具有统计学显著性的连续变量，并使用一种新型在线工具进行计算。FQ通过将FI、rFI或cFI除以样本量来计算。
58个纳入结果的中位数FI为7.0（FQ为0.109）。总体而言，二分变量比连续变量更脆弱。12个二分结果在统计学上均无显著性，rFI中位数为4.5（FQ为0.040）。46个连续结果在统计学上均有显著性，cFI中位数为9.1（FQ为0.113）。在58个结果中的21个中，失访患者数量大于各自结果的FI。按结果类别分析时，临床改善和并发症更脆弱，FI中位数分别为6.7和5.0。
连续结果比相对脆弱的二分结果更稳健。与其他报告cFI值的当前研究相比，KA与MA RCT中的连续结果也更稳健。cFI是一种新颖且有价值的工具，可用于评估连续结果的脆弱性，建议在报告p值时同时报告FI、rFI和FQ，以评估RCT的可靠性。
