CV Boot Crack

I was told today that I have a crack on both of my CV boots on my 2001 Kia Sephia. I had the entire axle replaced last year as well as the wheel bearings.I now hear a humming noise that I thought was just pavement noise.Could this be my axle getting damaged from the boots not working properly? Or will just replacing the boots be OK? And were the boots supposed to bee replaced when the axle was replaced?

There are two axles…a left, and, a right. Each has two CV boots. I think you only had one axle changed (either the left, or the right, axle). When an axle CV joint wears, it will click, click, click, when turning, at first. It can click for weeks, or months, before it becomes bad enough to change. It doesn’t hum…it clicks. The CV joint boots can be replaced.