Certain types of orthopedic surgery carry with them the risk of developing a blood clot in the post-operative period. Blood clots such as deep vein thrombosis (DVT) or pulmonary embolism (PE) can be life threatening. A pulmonary embolism usually happens when a DVT, often in your leg, travels to your lungs and blocks a blood vessel. This can lead to a decreased amount of oxygen circulating in the blood, it can cause lung damage and even lead to heart failure. Preventing the risk for the development of DVT or PE is imperative after surgery. Common orthopedic procedures such as total knee replacement, total hip replacement, and hip fracture surgery carry a greater risk of DVT/PE than other orthopedic procedures. Because of this, your physician will likely prescribe a pharmacologic agent to prevent the development of a blood clot after surgery.
Along with pharmaceuticals, mechanical devices are also used during orthopedic surgeries. Studies have shown that these are beneficial when used as an adjunct to anticoagulation therapy with medications. During and immediately after surgery, compression stockings and pneumatic compression devices are used. Often, our physicians will recommend patients continue wearing the compression stockings for a few weeks after surgery as well. These devices work to decrease venous stasis and increase blood flow velocity. This is especially helpful during the immediate post op period where patients are not as mobile.
There are a multitude of reasons why the risk for DVT/PE increases after orthopedic surgery, and depending on a patient’s medical history, that risk can be increased in the setting of chronic diseases. Here, we will go over some of the basic concepts and risk factors associated with the development of DVT/PE. Certain risk factors include those that diminish venous flow or return, increase viscosity of blood, and/or circumstances that decrease mobility. Age is one of the most easily definable risk factors secondary to decreased mobility and the presence of comorbidities. Some other risk factors include:
- Pregnancy or postpartum within 1 month
- History of major surgery within 1 month
- Varicose veins
- Obesity (body mass index [BMI] >25 kg/m 2)
- Oral contraceptives, patch, or hormone replacement therapy
- Malignancy or current chemotherapy or radiation therapy
- Confined to bed longer than 72 hours
- Immobilizing cast shorter than 1 month
- Tourniquet time longer than 45 minutes
- History of DVT or PE
- Family history of thrombosis
- Factor V Leiden/activated protein C resistance (clotting disorders)
- Medical patient with risk factors of myocardial infarction, congestive heart failure, or chronic obstructive pulmonary disease
- Hip, pelvis, or leg fracture within 1 month
- Stroke within 1 month
- Multiple trauma within 1 month
Today, there are many pharmacologic agents that fall into the category of anticoagulants, which means that they work to “thin” the blood, or decrease the viscosity to prevent the formation of clots. Each type of medication works on a cellular level, some in different ways, to prevent the blood from clotting. The specific type of medication used post operatively will be decided by your orthopedic surgeon based on your medical history, family history, or the presence of any other comorbidities. Common types of anticoagulation used here by our physicians include Aspirin, Xarelto, Lovenox, and Coumadin. These medications work slightly differently, all while preventing the risk of developing a DVT or PE.
These medications also come in different forms. Aspirin, Xarelto and Coumadin are all pills that are taken by mouth. Lovenox is given as a subcutaneous injection. When taking Coumadin, the blood must be drawn frequently to monitor what is called the PT/INR. Prothrombin time (PT) is a blood test that measures how long it takes blood to clot. A prothrombin time test can be used to check for bleeding problems, and it is also used to check whether medicine to prevent blood clots is working. Therefore, adjustments to the dosage of Coumadin can be made depending on what the PT/INR level is.
Taking these medications after undergoing a total joint replacement or hip fracture surgery is imperative. The benefits of these medications far outweigh the risks associated with them. One risk of taking these medications is bleeding. Certain measures can be taken after surgery to try to prevent the increased risk of bleeding. Using ice to decrease swelling is helpful. It is important to get moving after surgery to limit the risk of developing blood clots. Gentle exercise, range of motion, and walking are recommended. Pushing too hard or doing too vigorous of exercise in the immediate post op period can cause increased bleeding as well.
Be sure to ask our physicians what type of medication you will be given if you are considering total joint replacement surgery. These medications vary in cost and depending on your insurance coverage, they can be expensive. To be properly educated on these types of medications, it is helpful to know ahead of time which anticoagulant you will be given.