In Short, yes! Hard drives can be repaired but only for the purpose of Hard Drive Data Recovery. The drive needs to be repaired just enough to get the data. There are a lot of very fine mechanical machinery inside that even if the slightest knock where to occur, it would throw the entire system out.
So, you should never trust a damaged hard drive outside of data recovery. Once you have your data back, throw the drive away and don’t look back!