lb1lb1

sounded like splay leg
http://www.ehow.com/how_4479614_treat-splay-leg.html
card紙 is not strong enough
膠杯 doesn't sound like it would work as well, it will cut the bb's skin
need to use sponge (make up ones)
and it is better if you don't put the bb back after u put the treatment tool on the bb because the parent will bite at it and it might hurt the bb in the process
get calcium water every 2 to 3 days for the bb as well

lb1lb1

your cup isn't going to work
u need to tie the 2 legs together
keep them just a bit closer than normal width

easiest method is using make up sponge and poke 2 holes (about 1cm apart) and put the 2 legs through the holes to just above the knee
!don't remove it for 2 weeks!
after 2 weeks you can remove it and check it, if it is ok, make another one for another week and it should be heal
give it calcium water (i use calivet) every 2 to 3 days during the process as well