You can put limping dog in the search box or bump on knee.
This is a thread about CCL surgery, read the whole thread //www.curezone.org/forums/fm.asp?i=1779399
Our 12 year dog last year started limping so we got some medication. Did not get better and an X-ray showed cancer. I would go to a regular vet and if he does not know what it is I would ask for an xray.
We took him to Tufts for only one procedure a needle aspiration. They thought he had more spots but we did not want more testing. Turned out an aggressive bone cancer. After one month he could not walk anymore and we had to put him down. We kept him comfortable with pain medication and spoiled him with delicious food. Not easy but we did not want him to suffer.
We adopted an eight year old right away, it looks like she has Arthritis and I give her Synflex for dogs. There are also homeopathics, you can do a search for it.