Osteoarthritis (OA) is the leading cause of disability in adults and is associated with comorbidities such as heart disease, metabolic syndrome and depression.

As there is no known cure for OA, efforts are focused on prevention, particularly in high-risk groups.

One of the leading risk factors and therefore a focus of prevention efforts is obesity.

TOPS (The Osteoarthritis Prevention Study) is a joint project between researchers based in the USA and Australia with the aim of reducing the development of knee OA in the target group.

The researchers will recruit 1230 ambulatory women aged 50 years or older with obesity (body mass index greater than or equal to 30), no radiographic (less than Kellgren-Lawrence grade 1) or MRI evidence of OA in the eligible knee and no or infrequent knee pain.

Men will be excluded from the study due to the significant amount of data showing that women are nearly twice as likely as men to develop knee OA.

The lifetime risk of knee OA for people with obesity is 16 per cent for men and 24 per cent for women (Messier et al 2023).

TOPS builds on previous research that looked at diet and exercise separately as influencers in the prevention of knee OA.

It will involve a phase III, assessor-blinded, 48-month, parallel two-arm, multicentre randomised controlled trial, with intervention centres located in North Carolina and Massachusetts, USA; and Sydney, Australia.

The weight-loss goal for the intervention group is a reduction of 10 per cent of their baseline body weight by the end of one year, using a combination of an energy-restricted diet and exercise (two 60-minute group sessions per week, supervised by study interventionists).

This will be followed by three years of weight-loss maintenance.

The control group will receive four 60-minute group meetings per year aimed at promoting a healthy lifestyle as well as newsletters and text messages to help keep the participants engaged.

The primary outcome is the incidence of structural knee OA, which will be measured using the MRI Osteoarthritis Knee Score to determine the severity of individual OA features such as cartilage loss, development of osteophytes and bone attrition.

Secondary outcomes involve the assessment of knee OA symptoms using the Knee Injury and Osteoarthritis Outcome Score knee function subscales (including pain), the six-minute walk distance test and the SF-36 questionnaire to measure health-related quality of life.

The study will encompass training practitioners, such as physiotherapists, in the delivery of the program.

‘Using my knowledge and skill set as a physio, I have valued the comprehensive training I’ve received for the structured diet program, which is evidence based and designed by nutritionists, dietitians and a behavioural psychologist,’ says Emily Williamson, clinical trial coordinator in the Faculty of Medicine and Health at the University of Sydney.

‘This training enables a healthcare professional, such as a physio, to deliver a structured diet and exercise program, enabling participants to access holistic lifestyle interventions, reducing the financial and mental burden placed on the individual and the healthcare system.’

One of the benefits of the study, the researchers believe, is the support offered by a healthcare professional.

‘There’s evidence of the importance of a structured support system where people are accountable and can build self-efficacy,’ says Emily.

‘A group situation is great because there’s a feeling of having a shared goal and participants can get support from one another.

It would make it easier to deliver the program in a community setting and to identify people at risk before osteoarthritis develops.’ 

The Sydney-based researchers would like to hear from local physiotherapists with patients, family members or friends who would benefit from the study. Visit their website (here) for more information.  

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