Weight Loss & Hip Osteoarthritis: New Research Challenges Conventional Wisdom
A recent study is prompting a re-evaluation of treatment approaches for hip osteoarthritis (OA), suggesting that weight loss and exercise, while beneficial for overall health, may not considerably impact hip pain as they do for knee OA. The research, conducted by the University of Melbourne, Australia, compared a very-low-calorie diet combined with exercise to an exercise-only regimen in individuals with hip OA.
While participants in the diet-plus-exercise group experienced, on average, 8.5% greater weight loss than those solely focused on exercise, the study revealed no statistically significant difference in hip pain severity between the two groups at either 6 or 12 months.
However, both interventions demonstrated a noticeable advancement in pain levels. The exercise-only group reported a 2-point reduction in pain on an 11-point scale after 6 months, while the diet-plus-exercise group saw a 2.8-point reduction. Importantly, a larger proportion of individuals in the combined diet and exercise group achieved a clinically meaningful decrease in hip pain within the first 6 months. Furthermore, improvements in hip-related quality of life observed in the diet group at 6 months were sustained through the 12-month mark.
Study co-author Kim Bennell, PhD, explained the findings, noting the differing biomechanics between the hip and knee. “We thought that it may not be as effective as you find at the knee because there may be different factors driving at the hip; biomechanical factors might be more vital.” She highlighted the lack of robust research specifically investigating weight loss for hip OA, given the strong link established between weight and symptom management in knee OA.
The study’s implications extend to potential treatment timelines. An editorial accompanying the research questioned whether newer weight loss medications, like GLP-1 receptor agonists, could influence outcomes by altering body composition. Researchers acknowledge the need for further inquiry into whether more ample weight loss, or longer study durations, might yield more positive results.
Rheumatologist Nancy E. lane, MD, of UC Davis Health, emphasized the unique nature of hip OA. She explained that the condition is frequently enough rooted in underlying structural abnormalities of the hip joint – the shape of the femoral head or acetabular cup – leading to wear and tear. “There’s no therapy that can make it better, because the hip joint, the shape of the hip – either the femoral head or the acetabular cup – is off and it’s worn out,” she stated.
While weight loss can reduce stress on the joint, Dr. lane argues it’s a less critical factor for hip OA than for other forms of the disease. She also clarified that being overweight isn’t a primary risk factor for needing a hip replacement.
Ultimately, the study suggests that for individuals with painful hip OA, delaying surgical intervention in favor of weight loss may not be beneficial. “It was really important to know that this type of exercise and weight loss wasn’t going to have an effect on the hip,” Dr. Lane concluded, suggesting this knowledge could facilitate earlier consideration of surgical options. However, she stressed that thes findings do not apply to other joints like the knee, where lifestyle interventions can significantly improve outcomes.
The research was funded by the National Health and Medical Research Council, Australia, with additional support provided through grants to several authors.
