Knee and Hip Replacement Risks May Include Heart Attacks: Study

New research suggests that there may be an increased risk of heart attacks among individuals who have a hip replacement or knee replacement, particularly right after the surgery. 

According to a study published online this week in the Archives of Internal Medicine, researchers found that recipients of artificial hips and knees are about 30 times more likely to have a heart attack during the first two weeks after their operation, raising questions about what, if anything, doctors may be able to do to mitigate the danger.

Experts have long suggested that the risks associated with anesthesia and surgery are likely increasing the number of heart attacks among patients who receive hip and knee implants, particularly if they are older. However, the evidence was limited, with no real study done to measure or confirm the increased risk until now.

Researchers looked at the Danish registries for all patients who underwent a primary total hip replacement or total knee replacement between 1998 and 2007. They found data on more than 95,000 such patients, which was compared to a control group.

For a period of up to six weeks following surgery, researchers found that patients are at an increased risk of acute myocardial infarction, also known as a heart attack, with the highest risk within the first two weeks.

Those over the age of 80 were at the highest risk and those younger than 60 had little if any increased risk. Overall the rate of heart attacks was 31 times that of normal in the first two weeks after surgery.

Although the study did not establish a cause-and-effect relationship between heart attacks and hip or knee replacements, the researchers speculated that the procedures themselves may have a direct impact on heart risks. Clot formation could be promoted by cutting into the bone, the report notes, and blood loss or oxygen deprivation may also occur during surgery.

Researchers indicate that physicians should consider the heart health of individuals considering a hip or knee replacement, and determine whether additional monitoring is necessary during or after surgery.