Background Obesity is associated with the development of knee osteoarthritis (OA). The aim of this study was to examine the incidence of obesity in patients undergoing knee replacement (KR) for OA in Australia compared to the incidence of obesity in the general population. Methods A cohort study was conducted , comparing data from the Australian Bureau of Statistics (ABS) 2017-2018 National Health Survey with data from the National Joint Replacement Registry. The distribution of patients who underwent KR from July 2017 to June 2018 by BMI category was compared with the distribution of the general population, in age and sex subgroups. Results During the study period, 35.6% of Australian adults were overweight and 31.3% were obese. Of the 56,217 patients who underwent primary KR for OA, 31.9% were overweight and 57.7% were obese. The relative risk of undergoing KR for OA increased with increasing BMI category. Obese class 1, 2, and 3 women aged 55 to 64 years were 4.7, 8.4, and 17.3 times more likely to undergo KR than their normal weight counterparts, respectively. Men of the same age and BMI categories were 3.4, 4.5, and 5.8 times more likely to undergo KR, respectively. Obese class 3 patients underwent KR 7 years younger, on average, than normal weight individuals. Conclusions
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More than half of Australians who underwent knee replacement for osteoarthritis were obese, increasing the risk of having the operation at a younger age, especially among women.
A study by the University of Queensland Rural Clinical School (UQRCS) compared data from the Australian Bureau of Statistics (ABS) 2017-18 National Health Survey with the Australian Joint Replacement Association’s National Joint Replacement Registry. Orthopedics.
The researchers found that of the 56,217 patients who underwent knee replacement for osteoarthritis (OA), 57.7% were obese.
UQRCS Head of Research, Associate Professor Srinivas Kondalsamy-Chennakesavan, said the risk of knee replacement for OA was relative to a person’s body mass index (BMI).
“Obese women ages 55 to 64 were up to 17.3 times more likely to undergo knee replacement than their healthy weight counterparts, while obese men in the same age group were up to 5.8 times more likely.” ", said.
“Obese patients with the highest BMI ratio were also seven years younger on average when they underwent knee replacement, compared to people of normal weight.”
About 2.2 million Australians have OA and almost a third of adults are obese, according to the ABS.
Lead researcher Dr Chris Wall said weight loss was an important step in improving outcomes for people and Australia’s health system.
“Modest weight loss has been found to effectively reduce symptoms of knee OA, and obese patients who maintained a 10% body weight loss experienced significant improvement in pain and function,” said Dr. Wall.
“By 2030, more than 161,000 knee replacements are expected to be performed annually.
"Urgent national action is needed to shift our focus towards reducing obesity or Australia may face an increasing burden of revision knee replacement in the future."
This study was carried out in collaboration with Professor Richard de Steiger, Professor Christopher Vertullo, Dr James Stoney, Professor Stephen Graves and Ms Michelle Lorimer.
