One of my friends, not a tennis player, had a bunion and had to have surgery.
http://en.wikipedia.org/wiki/Bunion
A tennis friend of mine, who is in his 30s, had a small broken bone in the area where the big toe connects to the foot. There was no acute injury and it probably developed over time. This injury location is common especially to those who stress the foot such as ballet dancers. He is very fast around the court. He played on it in pain for a year or so. He is getting surgery next month and also has a torn tendon in that area.