(Portland, OR) -- The FDA has granted marketing approval for an implantable shock absorber to help patients with osteoarthritis of the knee. Oregon Health & Science University conducted research to validate the new treatment. Total knee replacement was recommended for people older than 60. But, younger people had to rely on physical therapy and anti-inflammatory medicine that isn't very effective in reducing the pain. OHSU is among five centers nationwide that tested the new approach, called MISHA, and will be able to offer the procedure in the coming months.