I just have one interesting thing to tell you. My brother was having problem with his knee & running and was seeing physiotherapist specialist for this kind of problems in Belgrade . And she told him that she was in some seminar of physiotherapist held in Seoul, South Korea and that she spoke with Nadal physio and that she asked him what will happen with him for 10 years . Nadal's physio told her that his knees are in bad condition, but they request from him to make him fit to play no matter what is the price.
So what was the prognosis in ten years time? Chronic pain? Limp?