Q: Two years ago, one of my dancers fractured her ankle and was out for six months. Upon her return, I cautiously allowed her to take pointe class, but treated her as if she was a beginner, because she was rolling out into supination, and I was fearful she would reinjure her ankle. Her mother feels I have held her back and changed to another studio. Did I make the right choice?
A: Yes, you did! I would have handled this situation in the same way. When coming back to class after a significant injury, there are bound to be compensations and weaknesses to work through. Whether the rolling out was because of the injury or she had a tendency to supinate before she fractured her ankle, it really doesn't matter. She must retrain those muscles for maximal support before heading full-tilt-boogie back into pointe class.
Dancers tend to fall off the outside of their pointe shoes whether they are standing flat-footed or on relevé. A great exercise to retrain this is to stand flat in their pointe shoes and toss a ball between their hands. This will help reteach the ankle joint where center is and at the same time strengthen the weaker muscles to do their job. Try this both in parallel and in first position. It's definitely a challenge and much harder than standing barefoot.
From there, dancers should revisit all the basic pointe preparation exercises and strengtheners. While I'm sorry you lost a student because of this, I know you made the correct choice.