MRI Shows Slower Knee Degeneration When Patients Lose Weight

May 2, 2017

Imaging can show a slowing down of cartilage degeneration in obese patients after they’ve lost weight.

Magnetic resonance images showed significantly lower cartilage degeneration among patients who lost weight, according to a study published in the journal Radiology. The researchers from the University of California San Francisco investigated the association of weight loss with progression of cartilage changes at MR imaging over 48 months in overweight and obese participants compared with participants of stable weight. Body mass index (BMI) over 25 kg/m2 was considered overweight and for obese, 30 kg/m2.  “For this research, we analyzed the differences between groups with and without weight loss,” said lead author, Alexandra Gersing, MD, said in a release. “We looked at the degeneration of all knee joint structures, such as menisci, articular cartilage and bone marrow.” Gersing is from the Department of Radiology and Biomedical Imaging at UCSF. Four centers participated in the trial that included 398 women and 242 men who were overweight or obese; they were a mean age of 62.9 years. They had risk factors for osteoarthritis or mild to moderate radiographic findings of osteoarthritis. The total group (640 subjects) was categorized into three groups according to their weight loss over 48 months: 1. Weight loss of more than 10 percent (82 subjects)2. Weight loss of 5 percent to 10 percent (238 subjects)3. Stable weight (320 subjects)  Two radiologists assessed cartilage and meniscus defects on right knee 3-T MR images at baseline and 48 months by using the modified Whole-Organ Magnetic Resonance Imaging Score (WORMS). Progression of the sub-scores was compared between the weight loss groups by using multivariable logistic regression models.  The results showed over 48 months, adjusted mean increase of cartilage WORMS was significantly smaller in the 5 percent to 10 percent weight loss group and even smaller in the group with less than 10 percent weight loss when compared with the stable weight group. The percentage of weight change was also significantly associated with increase in cartilage WORMS.  The researchers concluded that subjects who lost weight over 48 months showed significantly lower cartilage degeneration, as assessed with MR imaging; rates of progression were lower with greater weight loss. “The most exciting finding of our research was that not only did we see slower degeneration in the articular cartilage, we saw that the menisci degenerated a lot slower in overweight and obese individuals who lost more than 5 percent of their body weight, and that the effects were strongest in overweight individuals and in individuals with substantial weight loss,” Gersing said in the release. “Our study emphasizes the importance of individualized therapy strategies and lifestyle interventions in order to prevent structural knee joint degeneration as early as possible in obese and overweight patients at risk for osteoarthritis or with symptomatic osteoarthritis.”