New Knee for Obese Beneficial

Photo: Arms wound around knees

Obese or not is no criterion for or
against a knee replacement;
© Giovanni Borea/

Around 55,000 knee replacements are performed each year in England to relieve the pain and disability of knee osteoarthritis, according to the researchers. However, they state, in some parts of the country, surgery is offered only to patients who are not clinically obese on the grounds that obesity is itself a risk factor for knee osteoarthritis.

The research team reached its conclusions following a six-year study of two groups of people, all over the age of 45. The first group (325 people) had all had knee replacement surgery and the second group (363 people) had not. At the start and end of the study, all participants completed a validated questionnaire designed to assess their mobility, mental health and wellbeing.

The findings showed that, overall, the mobility of those who had had knee replacement surgery improved over the six years of the study, while it fell in the comparison group. When researchers restricted their analysis to those participants who were clinically obese (those who have a body mass index (BMI) of above 30 kg/m2), improvements in mobility appeared to persist and BMI was not a significant predictor of this improvement.

Professor Cyrus Cooper, Director of the ERC and Professor of Rheumatology at the University of Southampton, said: "The long-term improvement in physical function that we observed in patients who have undergone knee replacement surgery is striking when set against the decline that occurred in the comparison group.

"These benefits extended to those patients who were clinically obese. Our results show that as long as appropriate selection criteria are applied with regard to fitness for surgery, there seems little justification for withholding the operation from patients who are obese."; Source: University of Southampton