What is Deep Vein Thrombosis (DVT)?
DVT is a condition in which a blood clot (thrombus) develops in the deep veins of your body. This happens most often in the legs, either above the knee or below it. Blood clots form when blood cells stick together and form a clump.
While this condition itself is not life-threatening, a blood clot can break free - this is known as an embolism - and travel through your blood stream. This blood clot may then get "stuck" in the blood vessels of a major organ, such as the lungs, and cause a pulmonary embolism (called a PE).
A Significant Risk
Although DVT can develop after any surgery, patients undergoing major orthopedic surgery, (which includes hip and knee replacement and hip fracture repair), represent a particularly high-risk group.
In patients who did not receive any preventive measures, (also known as prophylaxis), studies have shown rates of DVT of up to 40 to 60%, 7 to 14 days following major orthopedic surgery. However, routine prevention, with appropriate methods, is considered to be standard of care, and has reduced the incidence to as low as 1.5%. Similarly, prophylaxis has reduced the occurrence of PE to less than 1%, and fatal PE is now rare.
Most symptomatic DVT occurs after hospital discharge, and the risk continues to be higher than expected for at least 2 months after surgery. Furthermore, DVT is the most common cause for readmission to the hospital following total joint replacement surgery.
Risk Factors for DVT
Here are some of the conditions that may put you at risk for developing DVT.
- Increasing age
- Birth control pills, pregnancy, and hormone replacement therapy (HRT)
- Cancer and its treatment
- Cardiac dysfunction
- Chronic respiratory failure
- Major surgery (abdomen, pelvis, lower extremities)
- Trauma (fracture of the pelvis, hip, or leg)
- Obesity
- Prior DVT Blood Clot
- Prolonged immobility, stroke, or paralysis
- Varicose veins
- Indwelling central venous catheter
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Learn More:
The more risk factors a person has, the greater the chances of developing DVT. Please check out the DVT Risk Assessment Calculator to find out your risk of DVT and to help you talk about DVT with your doctor.
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Contributing Factors
Common factors that contribute to the formation of clots in veins include:
- Prolonged bed rest and a decrease in activity may cause your blood to move more sluggishly through the veins. The slower blood flow increases the contact time between blood and vein wall irregularities, and also discourages naturally-occurring anticoagulants, (blood thinning agents), from mixing in the blood.
- During joint replacement surgery the process of preparing the bone to receive the new joint can release substances that stimulate clot formation in the blood. In addition, clotting, (also known as coagulation) – the body’s natural response to the presence of tissue debris – also increases.
- Damage to the vein walls, which can occur during surgery as the physician manipulates veins. Breaking tissue cells can release substances that promote blood clotting.
Signs and Symptoms after Joint Replacement
After hip surgery, blood clots often form in the veins of the thigh. These kinds of clots are more likely to break off and get trapped in the lungs causing PE.
After knee surgery, most clots occur in the calf. Although less likely to lead to PE, these types of clots are more difficult to detect.
DVT commonly occurs in just one leg, and symptoms can include any or all of the following:
- Pain or tenderness
- Swelling, discoloration, or redness
- Warmth of the calf or leg
People with pulmonary embolism (PE) are more likely to experience symptoms, which can include difficulty breathing accompanied by:
- Chest pain, rapid pulse, or fainting
- Low-grade fever
- Cough, with or without bloody sputum (phlegm)
However, in as many as half of all DVT cases, patients do not experience any classic symptoms at all.
Warning Signs of PE in Your Lung
- Sudden increased in shortness of breath
- Sudden onset of chest pain
- Localized chest pain with coughing
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Warning Signs of Blood Clots, Possible DVT in Your Leg
- Increased pain in your calf or thigh
- Tenderness or redness above or below the incision area
- Increased swelling in your calf, ankle or foot
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Prevention – go for the flow with compression, movement, and medication
The goal for preventing DVT is to keep your blood flowing through the deep veins in your legs. Usually, several therapies are used in combination.
- Elastic compression stockings and/or an external compression device (used in the hospital) designed to encourage the natural flow of blood through your veins.
- Physical movement and rehabilitation which usually begins the first day after surgery and continues for several months
- Anticoagulant medication, which may begin the night before surgery and continue after you are discharged from the hospital for up to 40 days or more.
Compression devices – stockings and boots
A common method of prevention of blood clots is the use of mechanical devices to encourage blood circulation in the lower leg.
- Elastic compression stockings may be provided to you prior to your surgery. These are generally more effective in preventing clot formation in the calf than in the thigh.
- Pneumatic compression “boots” are external devices that are strapped onto your legs in the hospital, and resemble “boots.” These “boots” apply pulsing pressures similar to the pressure that happens during normal walking.
Both the compression stocking and compression boots are passive therapies (they do the work for you). They are an important component in avoiding DVT and in achieving a successful recovery.
Keep it moving….a body in motion stays in motion
Getting patients moving as quickly as possible after joint replacement is an important and beneficial way of reducing the risk of DVT. Your physical therapy will most probably begin the day after your surgery.
A physical therapist will design a program for you that will include exercises to restore your joint range of motion, (ROM), improve your gait (the speed and vigor of your step) and exercises to strengthen your muscles, called isotonic or isometric exercise.
Medication – prevention and protection, to reduce your risk further
The benefits or prevention of DVT with mechanical compression devices have been documented. However, in many cases, when used alone in certain patients, it is often not effective enough.
The American College of Chest Physicians (ACCP), have issued official guidelines that recommend the use of these kinds of devices in combination with blood thinning medication, (anticoagulants), for the prevention of DVT events in high-risk patients.
There are several blood thinners that have demonstrated improvement in DVT prevention without any increases in other blood-related complications (such as increased bleeding). These anticoagulants include:
- Warfarin/Coumadin
- Unfractionated heparin (UFH)
- Low molecular weight heparin (LMWH)
In clinical studies, LMWHs have been shown to significantly reduce the occurrence of DVT when compared with warfarin/Coumadin – an important clinical benefit. These results have also been confirmed in other studies in orthopedic surgery indicating that LMWHs were more effective than, and as safe as, warfarin/Coumadin.
Outpatient therapy with LMWHs is both safe and effective. Your surgeon will decide which drug is right for you, and how long you will remain on it to effectively manage your risk factors.
Prior to hospital/rehabilitation discharge, options should be made available for patient instruction on medication self-administration, or, to teach caregivers how to administer the medication. Visiting nursing services may also provide this service.
Patient Responsibilities
You are the most important key to a successful rehabilitation following joint replacement surgery. In order to return to an active life style, you must also be an active participant in your recovery.
Having a positive attitude and commitment to your recovery is within your control, and therefore, totally up to you.
- Follow doctor’s instructions, especially regarding medications
- Keep scheduled appointments
- Examine legs daily for increased swelling or pain
- Wear support hose, change positions often or walk, and drink plenty of fluids
- Keep your legs elevated above the level of your heart while at rest
When to Call the Health Care Provider?
- If you experience worsening symptoms such as increased swelling, redness, warmth, or pain in the legs
- Any signs of complications from anticoagulation therapy such as: Unusual bleeding (e.g., nosebleed, bleeding gums, red or cola colored urine, black bowel movements which are not related to use of iron supplements, bruising)
- If you develop sudden onset of difficulty breathing, shortness of breath, or chest pain, go to the nearest Emergency Room immediately!
Stick with the schedule your surgeon prescribed for you!
- To help prevent blood clots take your blood-thinning medicine exactly as your surgeon has prescribed.
- If you are not sure when you should be taking your medicine, talk with your surgeon.
- To help you make sure you remember to take it on time, try setting an alarm, writing yourself notes, or asking a family member or friend to remind you.
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