Marley Rides author Jennifer Hart on "Life Passages"

Knee Surgery Gone Bad

Warning: This video is not for the squeamish. Marley Pratt was a 15-year-old, who had a total knee replacement due to metastasized lung cancer. Due to a malfunction in the surgical hardware, Marley's knee trick is more like a bizarre circus act or a gross yoga position. He owned it as a funny way of gambling for school lunch money.

Marley was an unusual kid. He looked at the world upside down, didn't talk until he was 5, and then baffled doctors as they tried to diagnose what was different about this child. Marley was healthy as an ox until he was diagnosed with terminal lung cancer. Given six months to live, Marley wouldn't give up—there were too many fun things to do, like riding his ATV, stunt bikes, horses, and anything else that went fast.