New survey was conducted to find out why some extremely obese people showed more knee pain relief from lap-band surgery than others.
According to researchers, the pain proceeds from the deterioration and related inflammation in knee joints caused in part by the extra weight they bear.
While the pain relief seen with lap-band surgery applied to all patients with osteoarthritic knees, researchers found that it was most helpful in the young men and women who lost the most weight.
For the study, published in the journal Seminars in Arthritis and Rheumatism, researchers examined 120 patients who underwent lap-band surgery between 2002 and 2015.
All were surveyed for what they remembered about their knee pain immediately before surgery, a year after their procedure, and for as long as 14 years later.
According to the survey results, men and women in their 40s experienced post-surgical knee pain reductions after one year of between 50 and 60 per cent; while those in their 50s, one year later, had pain reductions between 30 and 40 per cent; and those in their 60s, had reductions between 20 per cent and 30 per cent.
Pain relief persisted for a decade in all patients monitored.
People with BMIs in the upper 40s were just as likely to report decreased knee pain as people with BMIs in the lower 40s if they lost proportionally the same amount of total body weight.