Within the last year I have seen this twice and I’ve never seen it before. The person has a full leg cast bent at the knee at a 90 degree angle. They have a peg leg stand which goes over the cast which allows them to put some weight on the leg for ease of mobility. I’ve seen them online listed as hands free crutch.
My question is simple, what injury or surgery would be treated by setting the leg at a 90 degree angle? I've never broken a leg but I've know people with breaks in every leg bone (not at the same time) and I've never seen a leg set like that until recently.