Unexpected Consequences of Joint Replacement Surgery
30 Apr 2007
An English proverb cautions that "It is the unexpected that always happens". No doubt people looking back on their life can recall several of those unexpected and unpleasant events. But how often do these unexpected events happen in surgery?
Today an increasing number of people face hip and knee replacement operations.
They’re often concerned about the pain following surgery and long sessions of physiotherapy to recover joint mobility. But how many consider a coronary attack after the operation?
Dr. Justin de Beer is an orthopedic surgeon at the Henderson site of Hamilton Health Services in Hamilton, Ontario. He and his colleagues recently reported to the Canadian Orthopedic Association that a worrying number of hip and knee replacement patients suffered a heart attack following this operation.
The majority of these coronary attacks occurred within three to five days of the replacement. And 29 percent of patients had no previous history of heart disease.
To obtain this information Dr. de Beer and his colleagues analyzed 3,471 hip and knee replacements performed at their hospital from 1998 to 2003. They found that 63 patients had suffered a heart attack (1.8 percent) and seven patients (11 percent ) had died. He speculated that since daily electrocardiograms and blood studies had not been done, some patients might have had silent myocardial infarctions without their knowledge.
Another study known as POISE (Peri-Operative Ischemic Evaluation) shows a 12 percent rate of silent myocardial infarction after surgery for non-cardiac conditions. Moreover, 60 percent of these patients experienced another major cardiac event within the next six months.
These findings are, to say the least, startling. They show that a significant number of people entering hospital for a hip or knee replacement get more than they bargained for.
Several other studies show there’s always a significant downside to elective surgical procedures. For instance, last year the Canadian Medical Association Journal reported that major cardiac problems occur in 1.4 percent of patients over 50 years of age who have surgery for non-cardiac reasons. Of the patients who suffered a heart attack up to 25 per cent died. And for those who had a cardiac arrest during surgery 65 per cent died.
Looking at this problem from a worldwide standpoint the figures are more shocking. Of the 100 million operations done for non-cardiac reasons over 900,000 patients died from heart attack, suffered a non-fatal coronary or had a non-fatal cardiac arrest during surgery.
It’s strange that researchers did not also include smoking when calculating the risk of these procedures. Certainly being a smoker would also increase the chance of cardiovascular problems.
But why are so many patients developing heart problems? For one thing patients undergoing hip and knee surgery are not kids. One study showed that patients at greatest risk for either an actual heart attack or a silent one are over the age of 70, obese, suffering from diabetes or have both a hip and knee replacement done at the same time.
These events happen because the replacement of joints subjects the body to extreme stress. This triggers a host of physiological changes increasing the risk of forming a fatal blood clot.
It’s obvious one shouldn’t agree to the risk of this operation unless the joint is causing significant pain and disability. And the question is how many patients would defer hip or knee surgery if they fully understood these risks?
I suspect more patients would conclude that their pain and disability was not quite as bad as they thought. But today replacements have become so commonplace, patients tend to underestimate the possibility of unexpected events while getting a new joint.
"Why are you having a hip replacement?" I recently asked a patient. She had consulted me for an entirely different problem and happened to mention the prospective surgery. But I noticed she had little difficulty walking into the office and I wondered if she fully understood all the implications of this operation.
First impressions always linger with you. As a medical student at The Harvard Medical School I witnessed the first hip replacement. I decided then it was not a minor procedure. I haven’t changed my mind.
