I am a 28 year old guy with PFFD in my left leg. I haven't had any surgeries yet in my life for it. Because my foot is smaller, angled downwards and only has 3 toes, I've been able to wear a straight-legged prosthesis without anything "protruding" outwards. Basically, when wearing jeans, it looks pretty normal.
The problem I have is I can't sit in back-seats of cars, can't ride many roller coasters, can't sit in alot of theaters to watch movies, because my leg is always "straight". They couldn't put in an artificial knee, because with my foot, it is just too long, and the knee would be too low to be of much value.