My trap in the basement backs up every year. This time a plumber drain it with a camera. He said the trap had a big U which should be repaired. The pipe has no air . Also the pipe in front of the house near the sidewalk is elevated because of a tree that was removed and the roots damaged the pipe.

You piggybacked on a old thread so I moved you to one of your own,

The plumber said the trap had a big U which should be repaired. Why wasn't it repaired when he was there?

The pipe has no air If what you're saying is that there's no vent then the plumber should have informed you that was REALLY your problem and installed a AAV, air admittance valve, (see image) on the drain for a vent.
( Is this a licensed plumber?) Seems to me you should have been better informed.

the pipe in front of the house near the sidewalk is elevated because of a tree that was removed and the roots damaged the pipe.
This should be dug up and repaired. Backfall,( elevation) will cause clogs and if the pipes are cracked or damaged it will allow roots to enter and cause a blockage. It's only a matter of time so "bite the bullet" and get it done. Good luck, Tom