In theory, I guess you could. But I think there's a lot of drawbacks to it.
First you have to make the prosthetic... really costly for something properly made that isn't going to injure you and will last for years.. which is what it would take to alter the shape of your finger bones and muscles (which is what it sounds like you want to do)

I think what I'd probably suggest instead is guage how long you've been playing guitar. If it's only for a couple of years or less, then you're still at the very beginners stage of playing and have a long way to go. What happens over the next 10 years or so is that your fingers and subconscious wil learn to compensate for inadequacies in your playing. You'll gradually find other ways to play things. For instance if you're having trouble playing a certain chord because you can't reach a string. Learn to mute that string with your other fingers so that it doesn't sound. Or try a different variation of the same chord. If you can't play an open C chord, learn how to do barre chords instead.
With leads, just alter a couple of notes so you can play it or figure out a different way of playing it.

Just as a for instance; I'd been playing for almost 10 years when I realized I'd been playing a G chord the wrong way all that time. Now it just feels natural to play it the way I taught myself instead of the way the instruction books tell you to.