New Knees May Lead to Blood Clots

Pulmonary embolism risk heightened following knee replacement surgery

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Joint replacement surgery might seem fairly routine in today's on-demand health care system. The added risk for blood clots in the lungs following knee operations can add an extra complication.

Patients with heart disease, the elderly and smokers are most at risk for a pulmonary embolism following knee replacement surgery.

Others that may be at risk include women who take birth control pills, those with a family history of clots or a clotting disorder, and individuals who have previously had a blood clot.

"Talk to your doctor about post-surgical clotting."

A pulmonary embolism happens when a blood clot forms in the veins, usually in the legs or other limbs, then becomes free and travels to the lungs, possibly cause serious complications, including death.

Dr. Alma Pedersen, the study author, said that even with blood thinners, patients who receive knee replacement surgery still are at an added risk for weeks following such an operation. The potential complication is especially important to note since the number of knee replacement surgeries have increased substantially, and continued increases in the operation are expected in the future.

Researchers evaluated 37,223 knee replacement patients who had surgery between 1997 and 2007. They then searched for evidence of a pulmonary embolism in the 90-day period immediately following surgery.

They found that 441 patients, about 1.2 percent, were hospitalized for blood clots during that 90-day period after surgery. A review of patients records revealed that risk factors including older age, history of heart disease or a previous blood clot or an increased number of additional medical conditions added to the blood clot risk.

Investigators also found that the number of patients admitted to hospitals with blood clots after knee surgery has increased since 1997. Dr. Peterson said this was likely because diagnostic advances have enabled doctors to identify clots before they cause serious problems.

It was also discovered that patients who receive knee replacement surgery because of rheumatoid arthritis have a lower risk of clots than those with other conditions. Risk in all patients could be lessened by replacing one knee at a time, instead of both at the same time.

The research was published in the Journal of Bone and Joint Surgery.

Reviewed by: 
Review Date: 
July 28, 2011
Last Updated:
July 31, 2011