It will vary by person. Depends on how fast your swelling goes down after surgery, which is mainly influenced by your time spent icing and elevating the knee, as well as working ligaments and muscles by pushing bends and stretches of PT into the discomfort zone starting immediately after surgery. The ideal goal is to get to 130 degrees bend after 8 to 10 weeks of PT. Not everyone can make it, my right knee got to 130, but my left knee got stuck at 120, which is still good enough for most bending and climbing.