Knee replacement research reveals shocking figures

The first ever national study into the number of knee replacements in the US has been carried out by a group of researchers and doctors – who found that these kinds of surgeries are on the increase.

One in twenty Americans over the age of 50 now have at least one artificial knee, with many having to undergo a second, or even a third operation, as the metal or plastic joints wear out over time. Previously, doctors had only used anecdotal evidence to estimate how many people were living with artificial knees, but this study is the first that has used statistical analysis to come up with a more accurate number.

Dr. Daniel Berry, president of the American Academy of Orthopaedic Surgeons, and chairman of orthopaedic surgery at the Mayo Clinic, believes that the study is not just important for statistical purposes but also to help medical facilities estimate how many Americans are likely to need procedures of this kind in the future.

He added that procedures of this kind can often put a strain on healthcare services as there can be problems with infections and scar tissue, while older people sometime need two, or even three, replacement knee joints as Americans start to live longer.

Elena Losina, lead author of the analysis and co-director of the Orthopaedics and Arthritis Centre for Outcomes Research at Harvard’s Brigham and Women’s Hospital, will present the data at the American Academy of Orthopaedic Surgeons’ annual symposium in San Francisco. She believes that while the surgery is a serious procedure there will be a significant increase in the number of cases over the next ten years as people live longer and are able to stay active into their 60s, 70s and even 80s.

Researchers used data from hospitals and the US census to come up with their figures; the most recent statistics available were from 2009, when there were over 600,000 knee replacement surgeries carried out.

Taking into consideration how many patients from previous years would be still alive, Losina and her colleagues calculated that four million Americans are living with artificial knee joints; this figure also takes into consideration the 500,000 patients who are on their second or third artificial knee.

While Americans over the age of 80 account for most artificial knee surgeries, the procedure is starting to be carried out on people who are much younger, with many patients in their 50s or even their 40s. There are half a million people in their 50s who have artificial knees, while the number of procedures carried out on those aged between 45 and 64 trebled between 1997 and 2009.