Is it permitted to wear ace bandaces and kneee braces outside on Shabbat? Does it matter if there is an eruv? Does it matter if the person *can* walk without it but with discomfort/potential risk or does it not matter? (for example, if a person wanted to be outside on Shabbat in nice weather and it is safer/comfortable to wear the brace but it is not absolutely necessary, it is permitted?
It is permitted to wear it outside, even in a place that has no eruv, as long as it is on securely, that there is no fear that it night fall off wile you are walking. The reason it is permitted to walk with it outside is because it is considered an accessory to your body, because it is servicing it, by protecting you from pain, discomfort and possibly hurting it.