What You Should Know Before Knee Replacement Surgery


Researchers have pinpointed several factors associated with an increased risk of serious infections after knee replacement. Though uncommon, joint infections can develop after joint replacement surgery. Sometimes the infections occur immediately, but they can also develop weeks-and, rarely, years-later.

The infection can spread to the artificial joint, requiring one or more additional surgeries to remove the infected tissues and often replace the joint. Building on what doctors already know about risk factors for joint infection, a study published earlier this year in the Lancet breaks out the risks associated specifically with knee replacement.

British researchers analyzed the results of 679,010 knee replacements performed between 2003 and 2013 in England and Wales. They reviewed the patients’ medical records from the time of their initial surgery until an average of four and a half years later. By doing so, they were able to identify key factors associated with deep joint infection and additional surgery, including:

  • A history of diabetes, chronic obstructive pulmonary disease, liver disease, a connective tissue disease or rheumatic disease, or peripheral vascular disease (poor circulation in the hands or feet)
  • Age younger than 62
  • Male gender
  • A high body mass index (BMI)
  • An injury or an inflammatory joint disease such as rheumatoid arthritis as the reason for replacement
  • A prior infection in the knee being replaced
  • General, instead of local, anesthesia used during surgery

Missing among the risk factors are smoking and alcohol consumption, which the researchers couldn’t account for because neither were recorded in the patients’ medical records. However, in previous studies the two habits have been established as factors associated with infection.

WHAT ELSE YOU SHOULD KNOW: Joint replacement infections occur in about 1 percent of the approximately 700,000 knee replacements performed each year in the United States-a number that’s expected to rise to nearly 3.5 million by 2030.

WHAT YOU SHOULD DO: If you’re planning a joint replacement, you might be able to modify some of your risk factors before your surgery. For instance, if you have a condition that might make you more prone to infection, you can work with your doctor to get the condition under better control. If your BMI is high, losing weight before surgery can help. If you’ve already had joint replacement surgery, let your doctor know if you experience any symptoms of infection, such as worsening pain in the joint, redness, swelling, fever, and chills.