Hello Jo-Ann,
I have several thoughts and since you’ve not specified I’ll simply outline them all and you can take what resonates.
First, when there are significant therapeutic issues faced by a yoga teacher anm opportunity is presented to connect with their lineage. This may involve contact hours with the person or person who trained them in a sort of consultation capacity. Peers from teacher training may also be a helpful resource in such situations. Of course if that is not available AND the teacher is not completely comfortable addressing the student’s issue, then the student ethically should be referenced to a senior teacher with therapeutic expertise. At very least the student should be made aware of the choices so that they may mindfully choose.
In the early part of my teaching life I told several students that I was not a pre-natal teacher, that they would be best served studying the practice with someone who was, and then they opted to remain in my classes anyway. But I was clear and clean in that process and did what was needed to maintain my ethics. All too often we pretend to know something when in fact it is perfectly okay to say “I don’t know”.
Specifically to your A&P question, internal and external rotation of the foot can either come at the ankle or at the hip. If the rotation is on the ankle then working at the hip would be less than profound. So it is critical for the teacher to look at the entire alignment of the leg and see where the rotation is originating. In this case however it is more likely to be malalginment in the hip.
For this student I would want to make certain they had clearance for physical activity from their healthcare provider. Additionally I would want far more intake form them than “the person manages in day to say life”. It’s simply too vague for a focused assessment and subsequently, an effective protocol in Yoga.
Generally I would avoid open pelvis poses - Vira II, Trikonasana, Parsvakonasana Vrksasana, as well as Baddha Konasana. Use extreme care and apply a gentle asana practice exploring the student’s capabilities within the framework of their current healthcare paradigm.
These are the thoughts I can provide without seeing the student and having much more information.
Warmly,
gordon