This TINY (3 pound) Chihuahua, surrendered because her owner "didn't have room for her," had almost no use of her back legs, and walked balanced on her front legs, with her back legs held off the ground,  She needed surgery to repair the luxating patella on both hind legs.  She is shown here right after surgery,  but now, after just two weeks, she is like a new dog -- prancing around happily, no longer in pain!

Treatment cost: $1,000 (due to reduced vet fee; initial quote was $3,500)