There are several things that come to mind that might qualify as a "knot" such as a ganglion, lipoma, or even a bone spur. You need to have this looked at to get a good answer.
Posted By Vivian Abrams DPM on June 13, 2003 at 22:48:31:
In Reply to: knot on top of foot
posted by Shirley Lawless on June 08, 2003 at 21:29:01: