I have tendonosis. It attacks the tendons and if they tear, it makes it so the won't heal properly. I've have it in both Achilles and my bicep/shoulder. The 2nd surgery was an attempt to have it heal the second time, but it torn again during rehab and I just can't get the strength back, so my doctor decided not to operate again. It's mostly pain free, but very little strength, so we called it best option. My Achilles are sure a slow recovery! Sucks