Study objective

Temporary lower limb immobilization may be a risk for venous thromboembolism. The purpose of this study was to examine the 90-day incidence of venous thromboembolism among patients discharged from an emergency department (ED) with ankle fractures requiring temporary immobilization. Secondary objectives were to examine individual factors associated with venous thromboembolism in this population and to compare the risk of venous thromboembolism in patients with ankle fractures against a priori-selected control groups.

Methods

This was a retrospective cohort study using province-wide health datasets from Ontario, Canada. We included patients aged 16 years and older discharged from an ED between 2013 and 2018 with closed ankle fractures requiring temporary immobilization. We estimated 90-day incidence of venous thromboembolism after ankle fracture. A Cox proportional hazards model was used to evaluate risk factors associated with venous thromboembolism, censoring at 90 days or death. Patients with ankle fractures were then propensity score matched to 2 control groups: patients discharged with injuries not requiring lower limb immobilization (ie, finger wounds and wrist fractures) to compare relative hazard of venous thromboembolism.

Results

There were 86,081 eligible patients with ankle fractures. Incidence of venous thromboembolism within 90 days was 1.3%. Factors associated with venous thromboembolism were older age (hazard ratio [HR]: 1.18; 95% confidence interval [CI]: 1.00 to 1.39), venous thromboembolism or superficial venous thrombosis history (HR: 5.18; 95% CI: 4.33 to 6.20), recent hospital admission (HR: 1.33; 95% CI: 1.05 to 1.68), recent nonankle fracture surgery (HR: 1.58; 95% CI: 1.30 to 1.93), and subsequent surgery for ankle fracture (HR: 1.80; 95% CI: 1.48 to 2.20). In the matched cohort, patients with ankle fractures had an increased hazard of venous thromboembolism compared to matched controls with finger wounds (HR: 6.31; 95% CI: 5.30 to 7.52) and wrist fractures (HR: 5.68; 95% CI: 4.71 to 6.85).

Conclusion

The 90-day incidence of venous thromboembolism among patients discharged from the ED with ankle fractures requiring immobilization was 1.3%. These patients had a 5.7- to 6.3-fold increased hazard compared to matched controls. Certain patients immobilized for ankle fractures are at higher risk of venous thromboembolism, and this should be recognized by emergency physicians.

中文翻译：

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踝关节骨折急诊出院患者的静脉血栓栓塞：基于人群的队列研究

学习目标

临时下肢固定可能是静脉血栓栓塞的风险。本研究的目的是检查从急诊科 (ED) 出院的踝关节骨折需要临时固定的患者中静脉血栓栓塞的 90 天发生率。次要目标是检查该人群中与静脉血栓栓塞相关的个体因素，并将踝关节骨折患者的静脉血栓栓塞风险与预先选择的对照组进行比较。

方法

这是一项回顾性队列研究，使用来自加拿大安大略省的全省健康数据集。我们纳入了 2013 年至 2018 年间从急诊室出院的 16 岁及以上的患者，这些患者患有闭合性踝关节骨折，需要临时固定。我们估计了踝关节骨折后 90 天静脉血栓栓塞的发生率。Cox 比例风险模型用于评估与静脉血栓栓塞、90 天审查或死亡相关的危险因素。然后将踝关节骨折患者的倾向评分与 2 个对照组相匹配：出院时因不需要下肢固定的损伤（即手指伤口和腕部骨折）比较静脉血栓栓塞的相对风险。

结果

共有 86,081 名符合条件的踝关节骨折患者。90 天内静脉血栓栓塞的发生率为 1.3%。与静脉血栓栓塞相关的因素是年龄较大（风险比 [HR]：1.18；95% 置信区间 [CI]：1.00 至 1.39）、静脉血栓栓塞或浅静脉血栓形成史（HR：5.18；95% CI：4.33 至 6.20） 、近期入院（HR：1.33；95% CI：1.05 至 1.68）、近期非踝关节骨折手术（HR：1.58；95% CI：1.30 至 1.93）和随后的踝关节骨折手术（HR：1.80；95% CI : 1.48 至 2.20)。在匹配队列中，与有手指伤口（HR：6.31；95% CI：5.30 至 7.52）和腕部骨折（HR：5.68；95% CI：4.71 至6.85）。

结论

从急诊科出院且踝关节骨折需要制动的患者 90 天静脉血栓栓塞的发生率为 1.3%。与匹配的对照组相比，这些患者的风险增加了 5.7 至 6.3 倍。某些因踝关节骨折而需要制动的患者发生静脉血栓栓塞的风险较高，急诊医师应认识到这一点。