You also need to look at the lower control arms, these have a tendency to break the rubber bushing causing issues with steering and alignment as well...
If you have a bad strut this could also be part of the problem as well..
These are great little cars, but as the miles add up like say over 100K, I would replace both front struts, and inspect the lower control arm bushings as well as the ball joints... If the ball joint or bushing is done, in some cases its easier to replace the entire lower control arm..