Thank you... This seems like one of those basic things we should learn in elementary school -- the healing rates of various parts of our body. We should know what needs the most protection/care. I still do not know that information, and it seems that somebody has to be damaged in order for others to learn about it. Mentally putting "ligaments and knee cartilage" on my list of things to be careful about. I didn't know there was no regeneration there. :(