It's not exactly en pointe but related: back in the 1980s, Terry Frazier was flying contests in, IIRC, an ASW 20 using his prosthetic legs (he was a double amputee). I know he also went through getting approval for full hand controls in a 2-33, though I don't think he ended up needing or using them. There's an article in the Dec 1980 Soaring:
https://magazine.ssa.org/viewer?y=1980&m=12&p=26&o=0&q=terry%20amputee%20. Others from that era might recall more details. I met Terry at a nationals in Cordele and I know he was quite active for a while.
Chip Bearden
JB