Language has always been debated and changed. Words mean different things now than they did fifty years ago. Some words used long ago are considered offensive now, and vice versa. No matter how far I look back, though, the same terms are used to describe wheelchair users. However, more people now are aware that many find the word "cripple" offensive. The disabled community has reclaimed the C-word, and uses it freely with one another but discourages able-bodied people from using it (if you didn't know that, now you do!). There is one term that I have never heard a wheelchair user say. Only able-bodied people. This term is wheelchair-bound.
There's something strong and piercing about this word. I imagine someone tied to a wheelchair in chains and ropes, like 50 Shades of Gray except even more wrong and disgusting. The wheelchair keeps the person there at all times, and other people walk by looking down at them pitifully. And the wheelchair user is always sad, friendless, loveless. A pitiful sight, indeed.
Quite often in movies or TV, characters in wheelchairs resent the life imposed on them, either at birth or by a tragic accident, and often say to themselves, "If only I could get out of this chair!" It's sad.
Here's the thing about actual wheelchair users, from a person who has always used mobility equipment and knows a lot of people who also do: wheelchairs are not sad. No one is bound to their wheelchair. If anything, the wheelchair is bound to the user.
My scooter has been forced to put up with me, my butt, and my need for speed for five years. I'm sure if she (she is a girl and her name is Scarlett) had a mouth, she'd complain. If she had arms, maybe she'd force me to slow down. But she doesn't. She does her job. She allows me to go places and do things that I couldn't on foot. She's a vehicle for freedom. Thanks to Scarlett, I can go to theme parks and ride roller coasters. I can be a full-time college student. I can go out with my friends and family without having to leave early due to extreme pain and fatigue. My wheelchair enables me. It doesn't restrict me. Not being given this gift of alternative mobility is what would be restricting.
So, stop using the outdated and offensive term! The right term to use is wheelchair user or person in a wheelchair. If more people knew that wheelchairs are just an alternative form of mobility for people who don't have as much as others, there wouldn't be as much stigma around using wheelchairs. If whoever coined the term wheelchair-bound knew, they wouldn't have done it in the first place! Wheelchairs are freeing, and should not set someone apart this much.