Giving patients guidance on trail running shoes can be a challenge as the design of these shoes is different from non-trail running shoes. Essentially, trail running shoes have a more rugged outsole of varying degrees to facilitate better grip of uneven terrain. They are also lower to the ground and softer for better shock absorption.
The problem is all the research and development goes into running shoes so you do not have the same choices with trail running shoes as you do with regular running shoes. Whereas a manufacturer may offer 10 different styles of regular running shoes, it may only offer two or three trail running styles. Also, when it comes to the trail running styles offered, they usually do not come in widths. Another problem with trail running shoes is that they typically are not what podiatrists consider stable as most lack a firm heel counter and are not torsionally stable.
Due to these differences, your runners may experience more injuries with trail running shoes than non-trail running shoes so it is important to educate them as to the differences.
It is also fine to recommend patients run trails in their non-trail running shoes, especially if their runs include both or shorter trail run distances.