I did have something similar with an incision from a non-knee related surgery. I had a laparoscopic surgery, and my navel incision basically rejected the internal sutures used to close the incision. Like your doctor said, started a few weeks after surgery, it became irritated, red and partially re-opened and started to leak - but never infected (or at least seriously). Went on for about a month. It didnít clear-up/heal until I fished the sutures out myself as they started to push out. But once I got that irritation out of there, it closed up and healed within a week. Just keep a close eye on it.