There have been rare cases when people did have their limbs restored miraculously. Usually it’s right after the event (ie, somebody saintly sticks it back on and prays over it), but there have been some cases where people who have been limbless for years got a miraculous leg or arm (either by it growing back, or just appearing overnight - again, usually associated with a healing shrine or a miraculous apparition of a saint or saints associated with healing or being a physician).
But when this stuff happens, it is not something forced out of God. Someone freely asks, and God freely answers.
Praying for something, for yourself or others, is never going to hurt you (or them). If you pray seriously and persistently, either you will get what you pray for, or you will get a favor that is as good as what you asked for.
You may not know about it or recognize it at first, however. (As in the country song about thanking God for unanswered prayers.)
But if you ever have something big to pray about, like praying for restoration of a leg, why not?
And whether you get a physical noticeable gift like having a leg back; or you get it back in another form, like a prosthetic; or you “only” get courage and strength to find new ways to get through life, or relief from pain, or the ability to pray for other people’s souls – you have nothing but gain, instead of just having something bad that happened to you.
Of course, it helps to be someone holy with great trust in God, perfect prayer, blah blah blah.
But super-holy people with awesome prayer skills, or outright miracleworking, got to know God that well through imperfect prayer, and bad stuff happening to them, and a lot of doubt and pain. We don’t have the advantages that Adam started out with; we have to work on being open to God, and joining our wants and needs to His plans for us and all Creation. The more we can do that, the more it will all make sense.
I’m not a saint, and I’m not good at praying yet. But I know that we are co-heirs with Christ, part of His Body, and that we are called to use that for others and for ourselves.