Rising rates of obesity
among people younger than 65 may be the main reason for the rapidly increasing
number of knee replacements in the United States, according to a new study.
The findings dispel the
popular belief that aging baby boomers and weekend warriors are behind the
unprecedented rise in knee replacement surgeries, the researchers said.
The study authors looked at
data from 9 000 knee replacement patients that was gathered by more than 125 orthopaedic
surgeons from 22 states. The analysis revealed that 55% of patients younger
than 65 were obese, compared with 43% of those who were 65 or older.
Compared with those 65 and
older, twice as many of the patients younger than 65 were severely obese (5%
versus 11%, respectively). The younger group of patients also had higher rates
of smoking and lower mental health scores, the investigators found.
"What was once thought
of as a procedure for older people or those with sporting injuries is changing.
Our study shows that younger patients are more obese and experience the same
amount of pain and functional disability as older patients and in some cases
even more," study author Dr David Ayers, director of the Musculoskeletal Centre
of Excellence at the University of Massachusetts Medical School, said in a
university news release.
"What we're seeing is
that the rise in obesity rates in younger people is having a dramatic influence
on the number of total joint replacement surgeries. These are not premature or
unnecessary procedures," added Ayers, who is also chair and professor of orthopaedics
and physical rehabilitation at the medical school, in Worcester, Massachusetts.
The study was presented at
a recent meeting of the American College of Rheumatology and the Association of
Rheumatology Health Professionals in San Diego. The data and conclusions should
be viewed as preliminary until published in a peer-reviewed journal.
Knee replacement surgeries
are one of the most common procedures in the United States, with about 600 000
performed each year at a cost of $9.9 billion. The number is expected to grow
to 3.48 million procedures a year by 2030.
"Unless we see a
significant reduction in obesity, we will continue to see the necessity for
more and more of these procedures," Ayers said.
The American Academy of Orthopaedic
Surgeons has more about total knee replacement.
(Picture: Sore Knees from Shutterstock)