If you do some searches, you can see this series of laptop has been plagued with hinge problems. I really feel like it would not have been difficult for them to just design the things without using plastic to mount the fucking hinges. Someone in the assembly line really likes those hinges tight which leads to the plastic breaking where the hinge attaches to the back plate which holds the monitor.
My laptop was under warranty when I called to discuss this with Lenovo. The customer support person was hardly understandable, typical of tech support these days, and pretty much told me to fuck off - this design flaw wasn't covered under the warranty.
Go Lenovo... you used to be awesome. WTF happened?