The Vionic Womans walker.  This is my third pair that I have purchased.  Back in the old days you could measure your foot with one of those foot measurements and it would give you the size and width that you needed. Then you could try on a shoe in that size and it fit.  According to the foot measuring device (yep, in this day and age I found one) I should wear a 9.5 medium.  In the Vionic I wear a 9.5. In Nike, Sketchers, Rebocks..I have to go a 10 and up.  Ya gotta try them on.
  Secondly, these are a substantial leather.  They offer great support, and since I use them for walking, they are great for keeping my foot aligned.  Ergo..no injuries.
  My husband had knee problems.  I told him to try a pair of Vionics and it helped his knee.  If your old tennis shoes are leaning to the side with wear, it is a good sign that your foot and leg are not held in a good position.  My oldest pair of Vionics have turned an unreparable shad of off white, leather is peeling off, but the structure of the shoe is still sound.