Q. My 13 year old Yorkie isn't putting any weight on her right back leg. She might have been stepped on or landed on. She weighs 2 1/2 to 3 lbs.
DAVID ELBEZE, DVM, MRCVS
A. Yorkies can also hurt their knee cap, it's a condition called "patelar luxation" which is common in the breed. otherwise it might be a trauma just like you suspect, the best thing if it's very painful would be to take her to the vet to get it checked and he will prescribe some pain killers if there is no fracture. if it's just slightly painful, try to rest her for a few days and see if it helps (short walks, no running).