When we took on the care of Casper one of the first things we did was to buy him a new cage and because we knew absolutely nothing about care of birds at that time we presumed it would be suitable. It has an opening top which had a catch on it which Casper managed to get his foot caught in. Luckily I was just in the next room and was able to rush in and free him. He was very sorry for himself and limped for about half an hour but there was no lasting injury. I hate to think what would have happened if I had not been close by. Needless to say the catch was removed immediately. It was really superfluous anyway because there is no way he could open the top on his own, it is far too heavy.
Here is a picture of the offending article so you know what to beware of.