I’m on a task force for our hospital to look at the number of adults receiving total knee replacements. There’s been some concern that overutilization by the surgeons is becoming an expensive problem. I’m reaching out to all the list serves I receive orthopedic information from looking for any information I can find about national trends. Can you help me out?

Researchers at Brigham and Women’s Hospital in Boston, Massachusetts may have some information that will help. Using national data from inpatient (hospital) reports, they presented the following U.S. statistics:

The number of knee replacements in adults ages 45 to 65 has tripled in the last 10 years.

  • Over 600,000 total knee replacements are being done every year in the United States.
  • A total of nine billion dollars was spent on total knee replacements in one year (2008).
  • Total knee replacement is one of the top 10 fastest growing procedures in this country.
  • Over 40 per cent (41 per cent) of the adults getting knee replacements are between the ages of 45 and 65. The rest are over 65.
  • The number of knee replacements done each year is increasing in all age groups.
  • With the aging baby boomers and rising numbers of obese adults, these numbers are expected to continue to rise.

    It looks like rising rates of obesity and the growing number of older adults just aren’t enough to explain such an explosion in the numbers of total knee replacements being done. Naturally, the question comes up: what other factors can account for this huge increase in total knee replacements?

    A closer look at patient data showed that severe knee osteoarthritis is still the most common diagnosis (and reason for knee joint replacement). They did find an association between aging, obesity, and joint replacement. National statistics show that the number of adults medically classified as obese increased from 29.6 per cent to 33 per cent between the year 2000 and 2008.

    Further analysis showed that increased use of knee replacements may be linked with expanding indications. As you probably know, this means that surgeons are finding greater uses for knee replacements than just severe osteoarthritis in older adults.

    For example, sports-related injuries early in life have been shown to develop later into joint arthritis when those folks are in their 40s and 50s. This might account for the increasing numbers of knee replacements in the 45 to 65 age bracket. In general, increased athletic and sports participation may be contributing to joints wearing out earlier than for our grandparent’s generation.