No problem reagrding novelty of the eventual Patent claim since the "back to the future" movie would likely not fulfill the test for anticipation, i.e. it must both disclose AND enable the claimed invention.
In this case, since it was movie magic that tied up the shoes, it most likely would not fulfill the "enable" part of the anticipation test. ET voila, NIKE should be able to secure a patent on that shoe.
Cheers.