Can I join The Guards with foot pronation?

Hello Regan, Generally we can`t answer to medical issues on here as it would be down to the army doctors, however please see the bellow link as it will give you a better idea for medical issues that can be a bar from entry. https://jobs.army.mod.uk/how-to-join/can-i-apply/medical/ This page contains a brief sample guide to some of the conditions that might stop or delay you being able to join, however this is not an exhaustive list. You can still apply to join the army even if your medical history includes one or more of these conditions. Your application will be assessed on its own merits against medical standards for entry. Hope this helps.

How could I talk to the army doctors without calling them?

Your best bet would be to pop in/contact your local careers office, they may be able to get in contact with the Army doctors and get some guidance for you. Otherwise I believe you should continue with your application (being open and honest about your medical history, as they will find out) and a decision will be made during the process.