Senior Citizens Risk Pulmonary Embolism with Knee Replacement Surgery
Study finds 80+ elderly and those with three other common senior problems most at risk in hip, knee surgery
July 27, 2011 – Senior citizens - those 80 and over in particular - may not be the best candidates for knee replacement
surgery according to new research that found pulmonary embolism, an often fatal condition, was most common after replacement surgery in those
over 79 and those who had three other health problems common to the elderly.
When tennis star Serena Williams underwent emergency treatment for a
pulmonary embolism earlier this year, the world’s attention was drawn to this
often fatal medical condition which, although surprisingly not uncommon, is unfamiliar to most men and women.
Pulmonary emboli, or blood clots in the lungs, occur when a clot that forms within veins elsewhere in the body – often in
the lower legs or other limbs – breaks free and travels to the lungs, where it can cause serious complications. Pulmonary emboli can occur in
patients of any age and common factors associated with an increased risk of clot development include:
● oral contraceptive use;
● cardiovascular disease;
● prior clot formation;
● clotting disorders;
● family history of clots; or
● advanced age.
“The rate of
knee replacement has increased substantially worldwide, and continued increases
are anticipated in the future,” said study author Alma Pedersen, MD, PhD.
“The formation of clots, including pulmonary emboli, is a serious complication in patients undergoing knee arthroplasty.
Prophylactic measures, such as the use of blood thinners around the time of surgery, are used to reduce the occurrence of clots, but their
effectiveness in routine clinical practice following surgery is more uncertain.”
Study Details and Findings
The authors evaluated 37,223 knee replacement patients who had surgery between 1997 and 2007, looking for evidence of
post-surgical embolism in the 90-day period following surgery.
Risk Factors Common in Elderly
The authors found 441 patients (1.2 percent) were hospitalized for blood clots during the 90-day period following knee
surgery. An in-depth evaluation of these patient records revealed the following risk factors associated with clot development:
1. advanced age (older than 80 years of age);
2. history of cardiovascular disease;
3. history of previous clot; or
4. increased number of accompanying medical conditions.
The study also revealed the number of patients admitted to hospitals with clots following knee surgery has increased
since 1997, which Dr. Pedersen noted is most likely due to advances in diagnosis which have enabled physicians to identify clots before they
cause serious problems.
The study also notes that individuals who have a knee replacement surgery due to rheumatoid arthritis have a lower risk
of clots than those with other conditions. However, in all patients, the risk can be diminished slightly by replacing only one knee at a time,
rather than both.
Knee Surgery Still Considered Safe
Although knee surgery is still a generally safe procedure, which enables thousands of men and women each year to regain
mobility lost to injury or illness, patients should be aware of the risk of post-surgical clotting and talk with their physician about the
possible use of blood thinners and follow-up evaluations that may help to identify clots which may be treated before they cause problems.
Although blood thinners are typically prescribed only during hospitalization, the study suggested that physicians
consider extending the duration of blood thinner therapy into the weeks following surgery.
“Despite the use of blood thinners, patients undergoing knee arthroplasty continue to remain susceptible for clot
formation for several weeks following surgery,” Dr. Pedersen said. “Future studies should focus on the improvement of prophylaxis following
hospital discharge, particularly among elderly patients and those with a history of cardiovascular diseases or previous clot formation.”
More about joint replacement surgery and blood clot formation:
As the bones are prepared for the new joint in a replacement surgery, tiny microfragments of bone and tissue can become
dislodged and enter the bloodstream, “hooking” on vessel walls where they can allow additional debris to accumulate.
Eventually, this debris can form a clot large enough to impede the normal flow of blood, sometimes causing discomfort,
especially in the lower legs, one of the more common areas of clot formation. Most individuals, however, experience no symptoms of the forming
If the clot becomes dislodged from the vessel walls, it can travel through the blood stream, eventually lodging in the
lungs. In addition, long periods of immobility prescribed for patients undergoing these surgeries can cause blood flow to slow down,
increasing the of clot formation in these patients. If a patient develops swelling, redness or pain in the leg following discharge from the
hospital, you should contact your physician.
More about pulmonary embolism:
According to data from the American Thoracic Society, pulmonary embolism is a common complication of hospitalization and contributes to 5 to
10 percent of deaths in hospitalized patients. Some studies have estimated that more than 1 million Americans experience pulmonary embolisms
each year, with 100,000 to 200,000 of these events being fatal.