FRIDAY, Nov. 10, 2017 (HealthDay News) -- Need another reason to keep your weight under control?
Excess weight can cause dislocation of your knee and may even lead to a complication that results in amputation of your leg.
A new study attributes a surge in dislocated knees to the U.S. obesity epidemic.
"Obesity greatly increases the complications and costs of care," said study lead author Dr. Joey Johnson, an orthopedic trauma fellow at Brown University's Warren Alpert Medical School.
"As the rate of obesity increases, the rate of knee dislocations increases. The total number of patients who are obese is increasing, so we are seeing more of these problems," Johnson explained.
Knee dislocations result from multiple torn ligaments. Vehicle crashes or contact sports, such as football, are common causes.
For the study, the researchers analyzed more than 19,000 knee dislocations nationwide between 2000 and 2012. Over that time, people who were obese or severely obese represented a growing share of knee dislocation patients -- 19 percent in 2012, up from 8 percent in 2000.
Obesity is also linked to more severe knee dislocations, longer hospital stays and higher treatment costs, according to the study published recently in the Journal of Orthopaedic Trauma.
And the chances that a knee dislocation would also injure the main artery behind the joint and down the leg were twice as high for obese patients than for those whose weight was normal, the findings showed. This severe complication of knee dislocation -- known as a vascular injury -- can lead to leg amputation if not treated, the study authors said.
Patients with a vascular injury averaged 15 days in the hospital, compared with about one week for other patients. Their average hospitalization costs were just over $131,000 and $60,000, respectively.
The study authors said doctors should be especially watchful for vascular injury in obese patients whose knees are dislocated.
"That subset of obese patients who come in with complaint of knee pain need to be carefully evaluated so as not to miss a potentially catastrophic vascular injury," said study co-author Dr. Christopher Born, a professor of orthopedics at Brown.
Reducing obesity rates could help reverse the growing number of knee dislocations, the researchers suggested.
The U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases has more on knee problems.