Weight Loss Does Not Protect OA Knees Save

A new study presented at the Radiological Society of North America (RSNA) shows that obese people with substantial weight loss may significantly slow down the rate of joint space narrowing (cartilage degeneration) in the knee cartilage, but only if they lose weight through diet and exercise or diet alone; excercise alone is insufficient. 

Obesity is a major risk factor for osteoarthritis (OA), or acceleration of OA and ultimately the need for total knee replacement.

Gersing et al studied 760 patients from the from the Osteoarthritis Initiative who had a BMI >25 and had mild to moderate osteoarthritis.  Patients were divided into A) 380 patients who lost weight, and B) a control group of 380 patients who lost no weight.

Patients were followed for 8 years (96 mos) and studied according to how they achieved their weight loss : diet and exercise vs. diet alone and exercise alone. The researchers used MRI to quantify knee osteoarthritis at the beginning of the study, at 48 months and at 96 months.

Not surprisingly, cartilage loss was significantly less in the weight loss group, compared to the control group over the 96 months. However, this finding was only in those who lost weight through diet and exercise or diet alone.

Weight loss through exercise alone showed no significant difference in cartilage degeneration, compared to the group who lost no weight.

Weight loss has been shown to slow down cartilage degeneration in overweight and obese individuals, but it was unclear if the method used to lose weight made a difference.

These findings suggest that a comprehensive approach to weight loss may be needed to protect OA knees from further damage.