Can confirm, these are knife hinges. They were a short-lived attempt by the cabinetry industry to make the hinging mechanism seem invisible. Very few professionals or shops today want anything to do with them. Customers seem to feel the same way.

So after a lot of research and talking with quite a few cabinet shops. The consensus is that Amerock made a lot of different OEM hinges. This is one of those and there really isn't any stock to be found. The best replacement is the Youngsdale #3 hinge. I have the hinges in the photo and it fit perfectly. Hope this helps someone.

It's a form of strap hinge, but it will be hard to find something that large and elaborate. You might call a company like this and see what they have or where they can refer you: House of Antique Hardware

Pivot Door Hinges - Top And Bottom Set. Try the search and include top and bottom set.