An alignment shop will often 'bend' a trailer axle to get the tire in to spec. It is hard to tell from the picture but I am assuming that it is taken from the front looking back. Is the tire feathered? That is, are one edge of the tire tread ribs wearing quickly and the other edge seems flared up. It looks like the outside edge of the ribs in the photo are worn more, but I might be mistaken. If so then it has toe in. Run a tape measure across the front from the center rib on one side to the center rib on the other. Do the same with the back. If the front is a shorter distance than the back you have toe in. Camber can also be affected. That is the tilt of the tire.
Any alignment problem will wear tires quickly and increase the chance of a blowout. If you have toe out you are towing an unstable trailer and it is more dangerous and unpredictable. The cost of an alignment is less than the cost of replacing an axle and less than the cost of new tires. If the axle has other problems too, then replacement might be a good idea.
