Congenital genu recurvatum, or knee hyperextension, is a rare condition that occurs once in every 100,000 live births.
People with this condition, which appears more often in women, are born with a deformity in their knee joints. Their kneecaps are dislocated to the side, causing them to bend backwards to varying degrees. While some are still able to walk upright, others are forced to use their hands as an extra pair of feet.
The first documented accounts of the deformity go back to the early 1800s. In 1886, a girl named Ella Harper was featured in a circus and called "The Camel Girl" because she walked on all fours.
The condition has been associated with injuries, breech deliveries, and families that have ligamentous laxity or "loose ligaments," but nobody knows for sure what exactly causes it.
Knee hyperextension can also lead to knee and joint pain as well as stiffness from the eventual breakdown of cartilage and bone.
The woman pictured above was finally able to stand for the first time in her life after having surgery funded by donations. Many others aren't able to afford it.
Patients with knee hyperextension often have other conditions such as developmental hip dysplasia or clubfoot, which may cause them to walk on the side of the foot.
Physical therapy can help some people, but in severe cases, surgery is the only option.
Unfortunately, many of these people are made to feel like freaks every time they go out in public because they are constantly being stared at.
You can't blame passersby for being curious, but they too often forget that they are looking at human beings who aren't that different from them.
