I thought I’d bring this up in a whole post (hope @011ey doesn’t mind!) but short answer… yes and no? I’m fairly new to dnd BUT I have been thinking about this a lot for my next character who uses a cane like me! So as a whole post, maybe some DM/GMs and mobility aid users can add to it! This is based on my own experience with mobility aids (I haven’t ever used crutches) and what I see missed in media.
So it’s important to note if/how long your character can go without using their aids or using them wrong in situations like combat or chasing someone down. In media this is usually just “their bionic arm is too powerful for them to struggle with anything ever”. Which is just… not accurate? I’d suggest coming up with a table so you *can* do that if you need to but including a consequence for later, maybe it works like meta magic for sorcerers? Something like:
Movement is 20ft (or roll athletics with disadvantage, roll 1d4 daily and subtract that from certain abilities, slight of hand checks or stealth with disadvantage etc) BUT have a trade off
to ‘dash’ roll 1d4 damage
or to change speed to 30ft per second, take I pt exhaustion
Or either of those but only for x amount of time (2 per day)
To go without mobility aid take 1pt exhaustion/day
Use mobility aid improperly, take 1d4 damage (ac 10, HP 20) needs 1 gold piece to repair or 1 day repairing with tinkers tools
Having actual drawbacks for this was important to me because it’s what I experience, mobility aids allow me to do a lot but doesn’t ‘undo’ the all effects of my disability. Also, I do have to make trade offs, I don’t use my cane in the lab because I need both my hands and it gets in the way, or if I’m around my house I don’t because I can sit anywhere and move at my own pace. It might be worthwhile to look into some curses and how those mechanics work as well.
Beyond the sucky parts, there’s a lot of cool stuff you could do with mobility aids! I get tired easily of characters portrayed as just Sad and seeing their mobility aids as a hateful manifestation of their disability 24/7. Using my cane for the first time was amazing! I love having it when I do fieldwork to poke around for snakes (and have seen giant a giant rat snake while doing so). A lot of disabled folks love to make them their own, one of my favorite things I’ve seen is faux flowers winding up canes. If you have access to magic they could be tricked out! Crutches could be a spell casting focus, or a magical item with some cool mechanics. In dungeons they could be used to press pressure plates without being in range for damage (reach property?). They could even be boosted improvised weapons!
I hope this helps with some ideas, let me know if you come up with anything cool!