Possible torn ACl

Question
I was playing with my 1 year old lab Tasha yesterday, nothing rough or out of the ordinary, just throwing her the ball, I didn't notice her twist or fall or anything like that but then later that night she was limping.  This morning I had to carry her up the stairs, long story short I took her to the vet this afternoon and without any tests or anything they said it is a torn ACL, don;t they need to look into this a little more before they can be positive??  I am definately getting a second opinion, but do you think if she needs the surgery $3,500-$4,000 is around the right price? If you can give me any advice that would be great, she is like our child and we love her to death, this is an awful lot to swallow from last night to now, but if the money needs to be spent thats fine I'll have to get it together some how, please any advice let me know Thanks Jeff    Email-  jrt1470@comcast.net

Answer
I am very sorry to hear that.  I am glad you are getting a second opinion.  A torn ACL is tricky to diagnose.  X-Rays are of little help on soft tissues.  Any surgery seems to be outlandishly expensive, but I haven't heard about enough people having them done to say if it is typical.  

The one thing I can say is keeping her lean will help any joint problem.  Your dog definitely should be narrower at the waist than the hips and chest.
You should be able to easily feel the ribs, but not see them.  Each dog is
different.  Standard recommendations are a good place to start, but each dog
must have its food adjusted to its individual needs. Here is a link to a good illustrated guide,
http://www.longliveyourdog.com/twoplus/RateYourDog.aspx