You might not want to rush into knee surgery. Physical therapy can be just as good for a common injury and at far less cost and risk, the most rigorous study to compare these treatments concludes.

Therapy didn't always help and some people wound up having surgery for the problem, called a torn meniscus. But those who stuck with therapy had improved as much six months and one year later as those who were given arthroscopic surgery right away, researchers found.

"Both are very good choices. It would be quite reasonable to try physical therapy first because the chances are quite good that you'll do quite well," said one study leader, Dr. Jeffrey Katz, a joint specialist at Brigham and Women's Hospital and Harvard Medical School.