@HakaishinAndroid616 I've got a pretty fucked up knee, myself, and I can move as though I'd never injured it; granted, I end up feeling like my knee's going to explode afterwards and wishing I was dead, but I can do it. Largely, it's about how much pain you're willing to tolerate in order to not let your injury affect your daily life... If the knee doesn't heal properly, that's really all you can do. Sure, canes can help relieve the pressure, but they're damned inconvenient,
especially if you're young; the looks I used to get for using a cane were... Suspicious, to say the least.
That said, considering that an entire panel was shown in 2.1 of the MC putting on his boots and they look suspiciously like greaves and poleyns when he wears no armor whatsoever otherwise, I'm beginning to wonder if they're not magical armor that acts to support him in the way a cane or full-on crutches would; it'd also explain why he's so mobile, with seemingly zero pain, but is also unfit from active duty in his former line of work: if you need magic boots just to walk without issue, that's a massive liability.