Un-Hyping Recent Joint Replacement–MI Findings
A late-August headline on MedPage Today ominously read, “MI Risk Soars After Joint Replacement.” The article cited a recent Arthritis & Rheumatology study that found a more than 8-fold increase in risk of myocardial infarction (MI) for one month after knee replacement and a more than 4-fold increased risk during the month after hip replacement, all compared with equal numbers of matched controls who did not have joint replacement surgery.
A look at the absolute risk instead of the relative risk, however, reveals a different and less scary story. For example, among the 13,849 patients who underwent knee replacement, 306 (2.2%) had a heart attack within the first month after surgery. The rate of heart attacks among the equal number of people who did not have a knee replaced was 2.0%. Also, the increased MI risk seen during the first month after surgery steadily declined with increasing length of follow-up to the point where it became statistically insignificant at 6 months after surgery.
There’s little doubt that major orthopaedic surgery can stress the heart, but the many long-term cardiovascular benefits of joint arthroplasty, including advantages from increased physical activity and decreased use of NSAIDs, seem to outweigh the short-term risk of a heart attack.