Using modx (content management) with a php framework

[PyncDynctep]

I like CodeIgniter for php development, but I have a client with no tech skills that wants to make his own changes to his site. I taught him how to make pages in MODx (that was a feat in itself). Is it possible to develop a site with CodeIgniter and use MODx as the content management system? Will MODx mangle the framework?