Its not always a perfect fit. Depending on how the styles are taught, there are Arnis/Kali/Escrima moves that involve operating out of deep stances. This can be very difficult for a person with bad knees.
So true. In fact I originally learned to work from a deep stance and I tried to keep doing it even with my knee and ankle problems. My current instructor has knees messed up worse than mine and spent about a year getting me to work from a more natural, upright position. I'm finally catching on, and it's actually working better for me.
Clearly, finding an instructor who can help you is at least as important as the art you choose.