Out-toeing (duck feet), injury potential and prevention

A friend of mine with a prominent out-toe (like the image on the left) has just started running. He does about three miles at a time.

I am wondering how his gait will affect him. I find it easy to imagine a lot of shearing force on his knee. He's been to a running store and they analyzed his stride, but they didn't mention concerns about the duck footedness. Any ideas on what problems this could cause, or things he should look out for? Does anyone have sources about how to correct/help this? Maybe it can't be?