Sleeping interrupted...

For the past two nights, Brinley has woken up shortly after we put her to bed screaming bloody murder. I run in there to see what is wrong and there is her leg stuck in between the rails of her crib all the way up to her thigh!! How she does this, I have no clue! The only reason she can get her leg through the crib is I had to remove the bumpers because she was using them as a step to get out of her crib. Any suggestions what to use to cover the gaps in the railings that she won't use as a step???