Ortho Hors D'oeuvres (Answer):
To review, this is a 32 year-old male who presents with right ankle pain after tripping over a curb. He has plans to fly in 3 days.
Questions and Answers:
1) What is the injury?
The above radiographs demonstrate two obvious cortical irregularities: The AP film shows a nondisplaced fracture of the medial malleolus. The lateral shows a nondisplaced fracture of the posterior malleolus, with about 25% joint involvement.
2) What is the appropriate emergency department management of this injury?
This patient has two nondisplaced fractures of the distal tibia: the medial malleolus and the posterior malleolus. Taken separately, neither of these fractures cause ankle instability, and patients can typically be discharged with a walking boot and orthopedic follow-up within 7 days for observation of appropriate healing. However, because this patient has a bimalleolar fracture of the medial and posterior aspects of the distal tibia, he is likely to have an unstable ankle and possibly require operative repair. He should be placed in a posterior splint, given crutch training, and made non-weightbearing until follow-up with orthopedics within 3 days.
3) What additional recommendations should be made given the patient's travel plans?
This patient has two independent risk factors for deep vein thrombosis (DVT): his flight across the country and his cast immobilization.
Air travel is an established risk factor for DVT formation; long haul flights, such as our patient’s pending flight across the country, multiply a patient’s risk of DVT formation by 2-4 times. Stasis is a key causal factor. Studies have shown that sitting in aisle seats decreases the risk of flight-related DVTs by half, likely because the aisle seats allow for more freedom of motion. Similarly, subgroups of very tall and very short people have demonstrated even higher risks of flight-related DVTs. Very tall people have less relative room for their legs, and very short people can be too short for their legs to touch the ground, creating increased venous stasis as well as decreased range of motion.
However, stasis is not the only causal factor in flight-related DVTs. Comparison studies have shown that movement restriction at sea level only causes D-dimer elevation (and thus, procoagulant status) in 1% of patients, whereas 17% of patients at flight altitude have elevated D-dimers. The ultimate mechanism for this increased risk is still debated, but some experts believe that hypobaric hypoxemia plays a significant role in increasing coagulability
This patient’s recent fracture and subsequent cast immobilization also place him at increased risk of DVTs. Patients with nonoperative fractures and subsequent cast immobilization are at a 5-39% risk of DVT formation. This risk range encapsulates a number of different immobilization and fracture types, but even at its lowest is a significant increase from that of an undifferentiated population (.12-.18%).
Few medical or physical treatments have been demonstrated to decrease DVT risk in the setting of cast immobilization or long haul flight. Low molecular weight heparin has reduced the event of VTE in patients with lower limb immobilization, and in small observational studies, rivaroxiban has been shown to be noninferior to low molecular weight heparin. The incidence of significant bleeding in these studies has hovered around 0.14%. Aspirin has not been demonstrated to prevent DVTs, and is explicitly not recommended as pharmacoprophylaxis. The use of compression stockings (in tandem with leg massage and flexibility exercises) has decreased VTE events in patients undergoing long haul flights.
There are several existing guidelines regarding anticoagulation for DVT prophylaxis in the above settings. Regarding flight, the American College of Chest Physicians recommends against routine DVT prophylaxis in patients undergoing long air flight. They do, however, make an allowance that “high risk patients” should be evaluated on a case-by-case basis, and may benefit from anticoagulation. More specifically, the British Thoracic Society recommends 1-2 days of chemical prophylaxis for patients who have active cancer and are within 6 weeks of major surgery or trauma. For all other patients with pending long flights, they recommend hydration, below-knee compression stockings, and calf massage and exercises.
Regarding lower limb immobilization, the American College of Chest Physicians again recommends against routine DVT prophylaxis with the exception of high risk patients for whom a case-by-case evaluation should be made. The British Emergency Medicine Network recommends prophylaxis for patients who have lower limb immobilization and 2 or more of the following risk factors: high body mass, oral contraceptive pills, recent history of travel or pending travel, active cancer, family history of DVT or pulmonary embolus, or known clotting disorder.
This patient, with his absence of any other risk factors, does not need chemical prophylaxis. He should be safe to fly with an aisle seat, good hydration, and calf massage and exercise.
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