[QUOTE=JB;8817100]
Hiking the leg up is a neurological issue, not UFP. Either shivers as a genetic defect, or from EPSM/PSSM, or nutritional, or something else that isn’t shivers but presents similarly.
I asked about occasional, because you said “just on occasion, he’ll misstep with a back leg.”
sounds like a slipping/catching stifle, which is not as severe as UFP, or actual locking. Contrary to how it sounds, Upward Fixation of the Patella" is not the leg “fixating” in the up/flexed position. It is the patellar ligament getting stuck over the patellar hook, causing the leg to not be able to flex at all, it’s rigid, it’s stuck with the hock and stifle in the extended position.
Having difficulty backing up is also a symptom of shivers, or shivers-like issues. Unless a stifle is locked (which keeps the foot on the ground, leg unable to flex to take a step) a horse with purely UFP issues has no issues backing up.[/COLOR][/QUOTE]
In my gelding’s case, his leg would just momentarily “catch” behind him (in the same position as UFP), but then release with a sudden jerk upwards. He hit his own stomach a few times. The first time it caught and then released while I was trying to pick out his hooves was quite a surprise for me 
And he absolutely had issues backing. To be honest, haven’t tried backing him since starting the estrogen, but I’m guessing it will be a lot easier for him now. The worse the “catching” got, the more he resisted backing up.
