Mobile Compression Device - Prevent Blood Clots

foot pumps
Compression devices squeeze compressed air around the legs. Jodi Jacobson / Getty Images

One of the complications of major orthopedic surgery, such as hip replacement or knee replacement, is a blood clot of the large veins of the leg.  These blood clots, called a deep venous thrombosis, or DVT, can cause swelling and pain.  If the blood clot breaks free, it can travel to the lungs causing the possibility of a pulmonary embolism, a potentially fatal complication associated with these major surgical procedures.

Because of the risk of DVT after major orthopedic surgery, surgeons often use blood thinning medications to help prevent this complication.  The problem is, being on blood thinning medications also has possible complications including bleeding and stroke.  The goal is to find the balance between lowering the risk of DVT, while not causing problems from the blood being too thin.

In order to lower the chance of DVT, surgeons often use other strategies to help prevent the formation of a blood clot.  These may include getting patients up and moving as quickly as possible, wearing compression socks, and the use of mechanical compression devices.

Mechanical Compression Devices

Mechanical compression devices, or sequential compression devices (SCDs), are loosly wrapped around the lower leg, and intermittently inflate with compressed air causing a mechanical pumping action.  Typically, these mechanical compression devices are worn when in bed, and then removed when patients get up.

  They can be a bit noisy and cumbersome, and therefore compliance with patients wearing the devices is sometimes challenging.  Most often, patients would use these for a few days while they were in the hospital, but not once they left to return home.

A newer mechanical compression device is called a mobile compression unit and is designed to be worn when up and about.

  They are less bulky, and the pump can be easily carried on a belt or shoulder strap.  Now that patients are leaving the hospital more quickly, and some are even having outpatient joint replacement, it is important to develop methods to prevent blood clot that don't rely on being physically located in a hospital.

Do They Work To Prevent Clots?

A recent large, multi-center trial compared patients who used a mobile compression device after joint replacement to those who had usual blood thinning medications.  Some of the patients who used the mobile compression device also were given aspirin as a mild blood thinner, but none were given the more potent blood thinners (such as Coumadin, Lovenox, or others). 

The researchers found that there was no major difference in chance of blood clot (DVT) or pulmonary embolism in the patients using the mobile compression device versus those using traditional blood thinning medicines. 

Bottom Line: Should They Be Used?

Mobile compression devices appear to be a safe and effective method to prevent blood clot and pulmonary embolism after major orthopedic surgery.

  Patients may have different risk factors for developing a blood clot, and those at higher risk may require more aggressive intervention.

There is no perfect method to prevent all blood clots, and in the study cited, some patients developed blood clots and pulmonary embolism, even when taking appropriate preventative steps.  However, mobile compression devices look to be a safe, and effective, alternative to blood thinning medications in some patients.  Patients concerned about taking blood thinning medications may want to discuss this alternative with their surgeon.


Colwell CW, et al. "A Mobile Compression Device for Thrombosis Prevention in Hip and Knee Arthroplasty" J Bone Joint Surg Am, 2014 Feb 05; 96 (3): 177 -183.

Continue Reading