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Stop the Clot: Special Precautions after Arthroscopic Knee Surgery

Painful swelling in the leg after surgery may signal a blood clot. Blood clots aren't always dangerous. They may dissolve without any further problems. The real concern comes when a blood clot doesn't shrink and disappear. The clot can get larger and damage the blood vessel. Swelling and blockage of the blood vessel can keep the clotted arm or leg from getting enough blood.

Worse than that, a blood clot can break away from the wall of the blood vessel and travel in the bloodstream to the lungs, heart, or brain. Death or stroke can result. What are the chances of this happening? The risk is much less with medications called anticoagulants. Anticoagulants such as aspirin and heparin prevent blood clots.

The chances of blood clots increase under certain conditions. Open surgery of the abdomen or pelvis, hip, or knee has been connected to blood clots. Anyone can develop blood clots after surgery, but adults over 40 years are at greater risk. Anyone with a previous history of blood clots is at risk. People with heart disease are closely monitored for blood clots after any of these surgeries. Finally, the longer the operation, the greater the chance that blood clots will form.

What are the chances of blood clots after arthroscopic surgery? The arthroscope is a surgical instrument that allows doctors to operate without opening the body. Doctors can insert a thin tube with a tiny TV camera on the end into a body cavity or joint. The arthroscope guides doctors during surgery. Only a small hole or incision is required. Other surgical tools can also be inserted through this site.

Until recently, no one knew how often blood clots occurred after arthroscopic surgery. Medication to thin the blood and prevent blood clots hasn't been given routinely to these patients. A group of physicians in Switzerland studied patients who had arthroscopic knee surgery. One group of patients received medication to prevent blood clots. A second group did not take this medication. Patients in both groups were carefully examined before and after surgery.

There were many more cases of blood clots in the group who did not take the blood-thinning medication. In this group, 15 percent had blood clots. Meanwhile, only 1.5 percent of patients who took the medication had blood clots.

The risk of blood clots after arthroscopic knee surgery is high. Medications to prevent this problem should be taken for at least two weeks after surgery. Most doctors recommend a 30-day period of medication to give patients the best protection against blood clots.

References: Marc Michot, MD, et al. Prevention of Deep-Vein Thrombosis in Ambulatory Arthroscopic Knee Surgery: A Randomized Trial of Prophylaxis With Low-Molecular Weight Heparin. In Arthroscopy. March 2002. Vol. 18. No. 3. Pp. 257-263.

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