the pathologic cane using as i see it...
MARK IMMORTELL canonically. he has a cane canonically, now whether or not the game wants us to believe he uses it for real or it's an accessory... for real to me. in my mind's eye he has sciatica. it acts up on and off so sometimes he'll be prancing around like a goat swaying his cane like he's trying to hit people with it, sometimes he uses it for real, and sometimes he has a fanciful little wheelchair when the pain's too bad to stand on his two legs. in which case he still holds his cane for hitting people purposes. his cane is a constant thing.
Yulia... she also mentions Leg Problem in P2 so Joy the cane be upon ye. i think her deal is a repetitive strain injury of tendinitis in the knee & ankle, and she never got enough rest for it to heal properly, never did physical therapy, so now, like other types of tendinitis, it flares up from use & some movements/postures. as the rainy & cold season approach, she gets more and more sedentary because the weather makes tendinitis worse by stiffening the tendons, so it gets in vicious cycles of Stiff tendons from the cold -> even less easy to do some stretches to help with the pain -> tendons get stiffer from no stretchin -> even less easy to do some stretches... her cane is an on and off thing, but becomes regular as fall & winter roll around
Notkin as he grows up. in p1 & 2 his spoken dialog mentions (a) bad leg(s); considering his mom died in childbirth (likely His birth) in my mind's eye his bad leg(s) is attributed to having been pulled out of there Fucked Uply. mom didn't make it through a complicated birth and baby got a leg messed up when they hurried to get him outta here. adolescence and getting taller gets him apophysitis (a bone + cartilage inflammation/strain injury often seen in teens because the bones grow faster than the muscles around them) in his knee and he never gets to have the rest needed for it to heal properly so as an adult, while the pain is mostly gone, it flares up sometimes. he's way past giving a fuck what anyone might think about seeing him limp with a cane in hand so he periodically, but quite often uses one. also might use it to hit people.
Khan occasionally once he gets into his mind that it's not a big deal & if he needs it he needs it. he already has a messed up knee as a kid (p2 model bandage) but i'm still deciding how extensive of a wound that is. more than what that is i think this guy gets inflammatory arthritis as a plague residual symptom, and while most of it is concentrated in his hands, fingers and wrists, it sometimes, rarely, attacks his ankles & knees, which is when he gets on his legs wobbly like a newborn foal. while his coping mechanism for it is to lie down and suffer through gritted teeth because he still has in mind that showing pain is showing weakness and is undignified of a man of his rank (the imaginary kingdom he once had) he eventually, from being yelled at "hey moron CATCH" and thrown a cane at, gets into his mind that he should use one for such moments and not even his Mortal Enemy* will care. his own would be a fanciful thing, black-lacquered wood, silver rings, a silver dog's head at the end of the handle. too proud and proper to hit people with it but he can't say he doesn't think about it.
Burakh, later in his life (his 40s). he also has a bad leg as of Being In His Twenties, but copes and manages without a physical aid for a while. he's on homemade painkillers and various rest regiments (when he can). when it gets too bad & arthritis sets in around 40s he's on that wood and bone tool in a blink and keeps it. maybe his father used on in his old(er) age... he reuses it...