Taylor D’Amore, Guillermo Araujo, Ivan Salce, Nigel Rossiter.
Response/Recommendation: Chemoprophylaxis against venous thromboembolism (VTE) is recommended for patients with a fragility fracture of the pelvis or lower extremity as long as the risk of VTE outweighs the risk of bleeding given other medical comorbidities. The use of intermittent pneumatic compression (IPC) devices should be considered for those who cannot receive chemoprophylaxis.
Strength of Recommendation: Low.
Rationale: Fragility fractures are those fractures that result from low-level trauma, such as a fall from standing height, where mechanical forces would not ordinarily cause a fracture1. Patients frequently present with pain and limited mobility but may not be able to recall the inciting event2. The treatment spectrum varies from open reduction internal fixation to percutaneous fixation to non-operative treatment2.
Only one retrospective study was found with a dedicated focus on VTE in low-energy isolated fractures. In this retrospective review of 1,701 patients by Prensky et al., 71.8% (1,222) of the patients sustained lower extremity fractures. Up to 85.6% of patients with a lower extremity fracture received chemoprophylaxis in the form of low-molecular-weight heparin (LMWH), heparin, or vitamin K antagonists. The number receiving chemoprophylaxis rose to 94% when looking at only patients who sustained a hip or pelvis fracture. There were 19 clinically symptomatic VTE in patients with lower extremity fractures within 90 days of discharge. Seventeen of the 19 VTE occurred in patients with hip or pelvis fractures for an overall VTE rate of 2.6% in patients with hip and pelvis fractures and 0.7% for all other fractures. Female sex and high body mass index (BMI) were found to be statistically significant predictors of VTE3. It should be noted that 30.5% of the fractures in this study were classified as hip fractures. Hip fractures are specifically excluded from our recommendation as this question is addressed separately.
There remains a paucity of literature on this topic and the rest of the recommendation is based on studies that did not differentiate between high and low energy trauma. In a survey of 103 Orthopaedic Trauma Association (OTA) members, there was no consensus for the modality or duration of VTE prophylactic agent following pelvis or acetabular (P&A) fractures regardless of weight-bearing status, need for surgery or type of surgical intervention. In this survey, LMWH and aspirin (ASA) were the two most frequently prescribed chemoprophylaxis for patients receiving VTE prophylaxis4. For nonsurgical P&A fractures, 64.7% prescribed LMWH while 19.6% prescribed ASA. For surgically treated P&A fractures, 75.7% prescribed LMWH, and 7.8% prescribed ASA4. Contrary to practices of American surgeons, surveys of trauma centers in the United Kingdom found that 45% of P&A trauma units do not routinely prescribe chemoprophylaxis post-operatively and 56% do not prescribe chemoprophylaxis for conservatively managed patients5; 62% do not use chemoprophylaxis following cast immobilization after lower limb injuries6.
In a retrospective review of 901 patients who underwent surgical treatment of a fracture below the hip, thromboprophylaxis decreased the risk of post-operative VTE from 6.8% to 2.3%. While the exact mechanism of injury for these is not known, over 50% of the patients sustained an injury from a slip or fall6,7. An industry-funded prospectively randomized controlled trial (RCT) evaluating IPC devices found that when coupled with LMWH, these devices decreased the rate of VTE from 1.7% (LMWH only) to 0.4% (LMWH combined with IPC) in 1,803 patients undergoing a variety of orthopaedic procedures8.
A recent systematic review of 15 studies of individual risk of VTE due to lower limb immobilization after injury describes advancing age as the most consistent individual risk following injury type and BMI. However, physicians should take into consideration the limited evidence supporting thromboprophylaxis in these cases9. Also, early fixation, before 48 hours, of pelvic and lower extremity fractures should be noted as an independent predictor of VTE10. Another systematic review of 5 level I studies for surgical management of tibia fractures suggested no routine prophylaxis due to doubtful clinical benefit11.
With foot and ankle surgery, there is no consensus; some studies do not recommend prophylaxis in outpatient surgery patients without individual risks for VTE or those not requiring immobilization12–16. Furthermore, others advise using VTE prophylaxis in long cast immobilization, independent of the previous procedure, until weight-bearing or removal17–19. However, there is a bias in these studies: VTE events following Achilles tendon ruptures are greater than ankle fractures treated surgically or conservatory20. American College of Chest Physicians (ACCP) guidelines do not support routine prophylaxis, but IPC is recommended in this field21.
Further research is needed in the form of high-quality prospective RCT to determine the need for VTE prophylaxis in patients who sustain a fragility fracture of the lower extremity. Although there have been some attempts to create VTE risk assessment tools22,23, to this day none have been validated or standardized24. Until then, risk stratification based on other medical comorbidities should play a role in shared decision-making between the surgeon and the patient in determining the need for VTE prophylaxis in these patients. Specifically, patients treated surgically should be separately evaluated from those treated non-operatively, and the ability of a patient to frequently mobilize factored into the outcomes25. It is important to consider that while chemoprophylaxis has been shown to decrease the incidence of VTE, its impact on all-cause mortality and mortality from PE is up for debate26–28. Studies designed to answer this question should delineate symptomatic from asymptomatic VTE events. Additionally, broad use of VTE prophylaxis is not without risks with at least one study demonstrating that the risk of death from major bleeding on LMWH was greater than the mortality from PE avoided by its use29.
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20. Blanco JA, Slater G, Mangwani J. A Prospective Cohort Study of Symptomatic Venous Thromboembolic Events in Foot and Ankle Trauma: The Need for Stratification in Thromboprophylaxis? J Foot Ankle Surg. 2018;57(3):484-488. doi:10.1053/j.jfas.2017.10.036
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