Deep vein thrombosis in Orthopedics
We have learned well over the years that a venous thromboembolic event can develop after any major surgery especially when the lower extremities are involved.
DVT Thrombosis (DVT) is the formation of a blood clot within a deep vein, manifested by pain, swelling, redness or warmth at the affected area. Almost half of these episodes are asymptomatic but some can develop complications like Pulmonary Embolism (PE) when the blood clot dislodges and travels to the lungs.
There are many risks factors like Surgery, Trauma, Obesity, Smoking, Pregnancy and even some genetic conditions like antithrombin, Protein S, Protein C, Factor V Leiden etc., responsible for a slowing down in the blood flow with a high tendency to clotting after an injury to the blood vessel wall. Let us expose the factors contributing to the formation of a blood clot in the veins after orthopedic surgery:
1- Stasis: Stagnation of the blood flow through the veins increase the contact time between the blood and the vascular walls preventing the action of anticoagulants while being on a prolonged bed rest.
2- Orthopedic procedures encourage the presence of debris, fat or collagen material in the veins, and initiate the coagulation. While undergoing joint replacement surgery, the preparation of the bone with reaming, release chemical substances (antigens) stimulating blood clots into the blood stream.
3- Damage to the vein walls occurs during a surgical procedure while the extremity is manipulated, breaking intercellular bridges and releasing substances that promote clotting. Age, previous history of DVT or Pulmonary Emboli, Metastatic Malignancy, Varicose veins, Smoking, Estrogen use or Pregnancy, Obesity or genetic factors can also contribute to Thrombosis. The veins of the thigh are most likely to promote PE. Less than a third of patients present with the classic signs of calf pain, edema, distended veins or ankle pain.
I will set some objectives to render this paper more instructional in dealing with the ways orthopedists approach such phenomenon:
1- Prevention: Early mobilization, rehabilitation with leg lift, ankle motion etc.
2- Mechanical Prophylaxis.
3- Graded compression devices like stockings
4- Continuous passive motion, Continuous passive motion, External pneumatic compression devices.
5- Pharmacologic Prophylaxis with Aspirin, Warfarin, Low molecular heparin etc.
6- Diagnosis and in-hospital treatment.
7- Post-operative Treatment.
DVT Diagnosis and Treatment need to address the issues of stasis and coagulation.
A variety of therapies is generally used like with graded compression elastic stockings and external compression device upon admission to the hospital. Mobilization and rehabilitation will begin as soon as possible after the surgical treatment and may last for months. Anticoagulation may start the night after surgery and continue after discharge.
Since the length of an admission for an arthroplasty may average three to seven days, early movements are beneficial. Physical therapy consists in range of motion, gait training with isotonic or isometric exercises which usually begins the next day after surgery. Pain medication is supplied to facilitate this phase. Mechanical prophylaxis with leg lifts, active and passive motion will increase as well the blood flow through the femoral veins.
Graded compression elastic stockings are more effective for the blood clots in the thigh. Compressive passive motion, external pneumatic compression devices can help reduce the overall rate of DVT occurrence or even occasionally, an umbrella or any other kind of filter device may be inserted into the vein.
Pharmacologic prophylaxis uses an anti-coagulant agent with potential risk in causing bleeding but with the efficiency in preventing clot formation like with Aspirin, Warfarin, and Heparin. Aspirin is easy to administer at low cost with few bleeding complications but has not been proven to be more effective than any other agent never less, it has shown a greater protective effect on men than women.
Warfarin is the most commonly used agent in patient undergoing arthroplasty procedures. This medication interferes with the vitamin K metabolism in the liver to prevent the formation of certain clotting factors. It does take more than 30 hours to become efficient and reach its maximum effectiveness. It may be started the day before the surgery with low doses and then adjusted according to the changes in the blood tests. It can cause fetal damage.
Heparin (unfractionated or (LMWH)fractionated) inhibits the clotting cascade. The LMWH (Ardeparin, Dalteparin and Fraxiparine) were found to be more predictable and effective with fewer bleeding complications. They work faster than warfarin.
The diagnosis of DVT can be difficult. The most common used tests are Venography, Duplex or Doppler ultrasonography, Magnetic Resonance Imaging (MRI) and cuff-impedance plethysmography:
1- The Venography is performed with the injection of a radiographic material into a vein on the dorsum of the foot and X-rays of the leg and pelvis are taken to visualize the calf and thigh veins in order to detect any blockage.
Venography is very accurate but costly.
2- Duplex ultrasonography can easily identify clogged veins. Projected sound waves bounce off structures in the leg and create an image revealing the abnormalities.
3- Color Doppler imaging can also improve the accuracy. This test is noninvasive and painless with no radiation and can be repeated at will. It costs less than a venography, but require skills experienced operators.
4- Ultra-sonography is less sensitive in detecting thrombi in the calf or the pelvis.
5- Magnetic Resonance Imaging (MRI) is particularly effective in diagnosing DVT in the Pelvis and as effective as venography in diagnosing DVT in the thigh. It is non-invasive and allows simultaneous visualization of both legs. Unfortunately, MRI is expensive and has limitation because of not being able to be used in presence of implants like a pacemaker. More, this test can create claustrophobia.
6- Cuff-impedance plethysmography uses blood pressure checks at different level of the extremity (leg or arm) to determine the site of an occlusion or blockage, although this test was used extensively in the past, it is no longer recommended as a diagnosis tool because of its high rate of false-positivity.
Prevention of DVT:
We have established ways to avoid any Deep Vein Thrombosis above and we would like to elaborate a little. The risks in developing DVT extend to at least three months after the joint replacement procedure with a peak at the second to the fourth day post-operative or around the ten-day after discharge from the hospital.
As discussed, the issues of Stasis and Coagulation are always addressed and we used a combination of therapies in fitting the patient routinely with graded compression elastic stockings as well as an external compression device on admission to the hospital. In rare cases, a filter can be introduced into the vein especially if the patient has a history of DVT or demonstrate any increase in risks to develop a DVT. Anticoagulation may be started before or after surgical treatment.
Early range of motion of the extremity is imperative as well as gait training exercises. We like to prescribe isometric exercises as soon as it is possible after surgical treatment while anticoagulation medicine and pain relievers are administered. The continuous passive motion machine is now less and less used but can function as a tool to perform an elevation of the operated lower extremity.
Pharmacologic prophylaxis will use the anti-coagulant agents with possible risk of increase bleeding while preventing the formation of blood clots. The most common are Aspirin, Coumadin and Heparin:
1- Aspirin is cost effective and does not need to be monitored and has few bleeding complications. Many studies have shown its efficiency in men more than women. Unfortunately, it can’t be used in all patients.
2- Warfarin is definitively the most common agent used by orthopedists in practice. It interferes with the vitamin K metabolism within the liver to prevent clotting and take around 36 hours before reaching therapeutic levels and more to reach a full protective level. It needs to be controlled through an outpatient clinic. Warfarin needs to be avoided during pregnancy because of possible side effects to the fetus.
3- Heparin acts on the clotting cascade and is presented in two ways: a high (unfractionated heparin) or a low (fractionated heparin) molecular weights. The low molecular weight heparin (LMWH) have been found to be more predictable and more effective with less bleeding complications when used after joint replacement surgeries. Nowadays, the most common used are Enoxaparin, Ardeparin, Dalteparin, Froxiparin. Those agents work faster than Warfarin.
In the post-operative period, the next three months are critical and any patient needs to understand the possible risks in becoming victim of a deep vein thrombosis. As already stated above, we found two peaks during the second to the fifth day post-op and around the 10th day after discharge from the hospital.
The Food and Drug Administration (FDA) has recently approved the last LMWH Dalteparin sodium which can be used effectively only once a day for 14 days
Many orthopedists and now our dedicated hospitalists have adopted a routine protocol in using simply a five days of post op heparin followed by grossly, three months of Warfarin. We are constantly looking at better ways to decrease the risks of DVT, like by the use of regional anesthesia instead of general anesthesia with intraoperative heparin which demonstrated up to 50% in DVT reduction rate. Patients with obesity and history of DVT, are at risk and a closer surveillance can be offered with the use of Venography. We like to avoid any extended outpatient prophylaxis except for the most at risk.
The treatment is the same for both symptomatic or asymptomatic patients with thromboembolisms. If the blood clot is localized at the thigh in the femoro-popliteal vein, bed rest is implemented with the use of Heparin as described above, for 5 days followed by 3 months of Warfarin. Blood Clots in the leg veins generally do not require heparin therapy but Warfarin for six to twelve weeks is sufficient. These are the approach taken by most orthopedists to prevent the occurrence of a fatal pulmonary embolism or to reduce the morbidity associated with DVT.
In conclusion, I wanted to expose the way orthopedists like to approach this entity and if sometimes we do argue with the internist or the Primary care physician, it is because we do have at heart, the impression that we may have caused the problem with the extensive manipulation of the extremity. At the end, the goal is the same and we are looking for the best outcome.
Maxime Coles MD
1- Becattini C, Agnelli G, Schenone A et al (2012). “Aspirin for preventing the reccurence of venous thromboembolism”. New Engl J of Med. 367 (21): 1979-87.
2- Sobieraj M, Lee S, Coleman CL et al (2012). “Prolonged versus standard duration venous thrombo-prophylaxis in major orthopedic surgery: A systematic review”. Annals of Internal Medicine. 156 (10) 720-27.
3- Kakkos SK, Caprini JA, Geroulakos G et al. “Combined Intermittent pneumatic leg compression and pharmacological prophylaxis for prevention of venous thromboembolism in high risk patients”. Cochrane data base Syst Review (4).
4- Tovey C. (2003). “Diagnosis, investigation and management of deep vein thrombosis”. SMJ. 326 (7400): 1180-1184.
5- Ozbudak, Omer, Erogullari. Ismail, Candan et al. (2014). “Doppler ultrasonography versus venography in the detection of deep vein thrombosis in patient with pulmonary embolism”. Journal of Thrombosis and Thrombolysis. 21 (2): 159-162.
6- Januel JM, Ghen G, Ruffieux C, et al (2012). Symptomatic in-hospital deep vein thrombosis and pulmonary embolism following hip and knee arthroplasty among patients receiving recommended prophylaxis: A systematic review”. JAMA. 307 (3): 294-303.
7- Cited orthopedic articles and publications:
a) DVT Prophylaxis after Total Joint Arthroplasty by Peter Hanson MD, Grassmont Hospital, La Mesa CA: “Prophylaxis, Controversies in agent selection”
b) DVT Prophylaxis after Total Joint Replacement by Paul Lachiewicz MD, Chapel Hill NC: Multimodal approaches, Clinical manifestation and Evidence base.
c) DVT prophylaxis after Total Joint Replacement by Russell Hull MBBS, MSC Professor in Medicine. University of Calgary: “Current Guidelines. risk stratification and clinical implication of prophylaxis.
d) DVT Prophylaxis after Total Joint Arthroplasty by Eugene Viscusi MD, Professor in Anesthesiology, Director of Acute pain service, Thomas Jefferson, Philadelphia, PA: “Challenges in co-administration of DVT Prophylaxis and Anesthesia.