Does weight loss surgery relieve pain?

New research shows bariatric surgery can contribute to long-lasting improvement in pain and physical abilities.

Weight loss surgery has many proven benefits, including reducing blood pressure, improving blood sugars, and reducing cardiovascular risk. Now, data from a large multicenter study of bariatric surgery in the US suggests that long-lasting improvement in pain and physical function can be added to this list.

What did the study look at?

This study followed nearly 1,500 people for up to seven years after they had either Roux-en-Y gastric bypass or sleeve gastrectomy, the two most common bariatric surgery procedures. Most of the participants were female (80%) and white (82%), with Hispanic (4%) and Black participants (11%) less well represented. Their ages ranged from 38 to 55, and all were diagnosed with severe obesity (a body mass index of 35 or more).

Before their surgery, participants filled out questionnaires that reported on their physical abilities, pain, health and quality of life. Many were also tested for measures of physical function and mobility, such as being able to walk 400 meters in seven minutes or less. Some have reported severe or even disabling knee or hip pain, a symptom of osteoarthritis. Assessments were repeated annually for up to seven years.

What were the findings?

When the study was completed, 41% to 64% of participants reported improvements in body pain and physical function, as well as objectively measured walking ability. In addition, 65% to 72% of those with osteoarthritis symptoms felt less knee and hip pain. And 41% of those who could not walk 400 meters in less than seven minutes before surgery could now do so.

Not all measures were better; for example, medication used for back pain before weight loss surgery and at the end of the study remained the same. It is also worth noting that not everyone experienced improvements in pain and physical function. And the lack of a control group that didn’t have weight loss surgery makes it hard to be sure whether the positive changes were due to surgery, or whether one type of surgery was better than the other.

Why are these results impressive?

We know that the improvements in health and physical function after bariatric surgery are greatest in the first one to two years after surgery. Between three and seven years after surgery, the positive effects on weight, cardiovascular and diabetes health measures, and health-related quality of life generally decline, although the net effect remains positive overall.

Most studies of joint pain, physical function, and work productivity after weight loss surgery have been limited to no more than two years of follow-up. As a result, it is unclear how long people can maintain improvements they make after surgery. This study shows evidence of long-term positive changes in important clinical outcomes that matter in daily life: how much body or joint pain people experience, what tasks they can perform for themselves, how mobile they are and how they feel about their quality of life.

Why does obesity worsen joint pain?

Obesity contributes to damage to the soft tissues in the joints (note: auto download), which can lead to osteoarthritis, a progressive disease caused by wear and tear on the joints. The hips and knees are most affected. Each pound of body weight puts four to six pounds of pressure on each knee joint, and people with obesity are 20 times more likely to need a knee replacement than those who are not overweight.

The bottom line

Obesity clearly has harmful effects on the joints. Bariatric surgery, which is an effective treatment for significantly reducing body weight, can improve pain and physical abilities, and reduce hip and knee osteoarthritis symptoms.

Additionally, for those considering total knee replacement surgery, weight loss from bariatric surgery can reduce the risk of complications (such as infection, blood clots, stroke, or heart attack). Even better, it reduces the chance of needing total knee replacement at all.

Taken together, these results show that bariatric surgery can have long-lasting effects beyond what we normally think of in improving blood pressure, blood sugar and general health; it can reduce pain and also improve physical function and quality of life.