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Brisbane – The extra weight that overweight people put on their knees is the number one risk factor for osteoarthritis of the knee.
According to a study, obese people need it ANZ Surgery Journal (2022; DOI: 10.1111 / ans.17689) not only use a knee replacement more often. Operations are also required for them at an early age.
More than half of Australians who need knee replacements for knee osteoarthritis are obese. The proportion is significantly higher than in the general population (57.7% vs 37.4%), which demonstrates the importance of the obesity risk factor, particularly pronounced in osteoarthritis of the knee, as the two knee joints have to support and move almost the entire body weight.
Surgeon Christopher Wall of Toowoomba Hospital, which belongs to the University of Queensland in Brisbane, noted that an unusually large number of young people need a new knee joint. Comparison of an Australian Orthopedic Association patient registry with a National Health Survey confirmed this impression.
The percentage of obese patients was particularly high in the age group between 45 and 54 years. Women were affected more often than men. In the case of Grade 1 obesity (BMI 30 to 35), Wall calculates that women have a 7.5 times greater risk of knee replacement. In men, the risk was increased by a factor of 3.2.
For grade 2 obesity (BMI 35 to 40), the relative risk was 12.2 for women and 5.4 for men. Women between the ages of 45 and 54 with grade 3 obesity (BMI over 40) required total knee arthroplasty 24.9 times more often than normal-weight women of the same age. In men with grade 3 obesity, the risk was increased by a factor of 7.0.
In contrast, the risk for men and women with grade 3 obesity aged 75 to 84 years was only slightly increased (relative risk 2.2 and 1.5, respectively, compared to people of normal weight).
The mean age at surgery was 71.3 years for women of normal weight. In grade 1 obesity, the operation became necessary at the age of 68.5 years, in grade 2 obesity at 66.5 years, and in grade 3 obesity at 64.1 years. Women with grade 3 obesity therefore required joint replacement 7.2 years earlier.
For men the difference was 7.3 years: with grade 3 obesity, the operation was performed at 63.7 years compared to 71.0 years with normal weight.
British orthopedists have come to a similar conclusion. Nicholas Clement and associates investigated the Journal of Orthopedic Research (2020; DOI: 10.1002 / jor.24460) for the 3 degrees of obesity a previous knee replacement time of 4.7 years, 6.7 years and 10.5 years (for both genders together). There, an earlier time was noted for a 3.1 year, 5.2 year, and 7.4 year hip replacement operation for the 3 degrees of obesity. © rme / aerzteblatt.de