Obese children who experience a common above-the-elbow fracture (called a supracondylar humeral fracture) are at greater risk of bone, joint and nerve damage that sets them up for long-term health problems, the study found.
"Something as simple and common as falling onto an outstretched hand while playing at the playground can have far greater health consequences for children who are diagnosed as obese," said senior author Michelle S Caird, assistant professor in the department of orthopaedic surgery at the University of Michigan Medical School.
The reasons are still unclear, but some studies have suggested that high-fat diets may interfere with the absorption of calcium in the intestines, making bones more fragile.
"It's important that children get the proper amount of exercise in order to strengthen their bones early in life," said Caird.
The study is believed to be among the first to assess the implications of obesity on this type of fracture, researchers said.
Similar studies have shown that overweight children who break their femur (or thigh bone) are more likely to need bigger surgery and have more complications than children who are not overweight, they said.
The findings appear in the Journal of Bone and Joint Surgery.