Hip and knee replacement for osteoarthritis increase short term risk of heart attack

People with osteoarthritis who have a total knee or hip replacement need to be aware that they may be at greater short-term risk of heart attack, according to a new study in Arthritis & Rheumatology.

Recent research suggests that joint replacements may improve heart health for people with osteoarthritis, so a team set out to investigate the association further. They looked at data from:

• 13,849 people aged 50 years and older with knee osteoarthritis who had total knee replacement surgery and compared them to 13,849 people of around the same age who did not receive surgery;
• 6,063 people aged 50 years and older with hip osteoarthritis who had total hip replacement surgery and compared them to 6,603 people of around the same age who did not have the procedure.

Over the four year follow-up period, 306 people with knee osteoarthritis who had knee replacement had a heart attack, compared with 286 of the control group. The risk of heart attack was significantly higher for the knee replacement group in the first month after surgery, but this declined over time.

In those with hip osteoarthritis who had a replacement, 128 people had a heart attack during follow-up, compared with 138 controls. Heart attack incidence was higher for hip replacement patients in the first six months after the procedure, before reducing to a lower level than those who did not have surgery.

People who had hip or knee replacement were at greater risk of deep vein thrombosis and pulmonary embolism years after the procedure, compared with controls.

“Our findings provide the first general population-based evidence that osteoarthritis patients who have total knee or total hip replacement surgery are at increased risk of heart attack in the immediate postoperative period,” explains Prof Yuqing Zhang who led the work. “The long-term risk of heart attack was insignificant, but risk of blood clots in the lung remained for years after surgery to replace a hip or knee damaged by osteoarthritis.”

One explanation for the findings is that the effects of anaesthesia could impact on the cardiovascular system. Alternatively, changes in medication for people with osteoarthritis during the surgical period could contribute to increased heart attack risk.

“Regardless, our findings suggest that the immediate postoperative risk of myocardial infarction following total joint arthroplasty may have been previously underappreciated, and further measures to prevent this serious event may need to be considered,” the group concludes.

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