Rebel did the exact same thing when he was 8 months old! He already had the luxated patella in his rear left leg, but the jump tore a ligament.
I took him to a wonderful surgeon in Gordon, Ga, who completely understood my reservations about having my baby anesthetized ( he weighed barely 4 lbs at the time) and repaired Reb's leg while I was there.
He stayed overnight, and after a couple of days of complete rest, my problem was keeping him from overdoing it and re-injuring the leg. He's had no problems with that leg at all since the surgery. Once the stitches were out I'd fill the bathtub and support his belly while he "swam". The vet said that was great physical therapy for him.
Good luck with your baby!
__________________ Kim , Rebel ,and baby Dixie 
RIP my sweet Lucy |