I know a lady in her 50s who just underwent knee replacement surgery.  They gouged open her leg, snipped off tendons attached to her leg muscles, and sawed the existing bones out, including parts of the leg bones.  Then they inserted a new knee made of metal and plastic. 

That was right around Thanksgiving weekend.  No more than 2-3 weeks later, this woman was walking.  This is absolutely amazing.  I'm over the fact that doctors can replace bones with pieces of metal.  That's cool in itself, but I'm over it.  The part that I'm amazed at is how quickly this woman recovered.  Sure, she went through (and continues to go through) a rigorous physical therapy program.  They had her out of bed within a couple days of the operation, and they continued to push her beyond her limits.  That's the nature of the recovery program.  But I'm still completely amazed that a person can have a piece of their leg sawed off and replaced by a chunk of lifeless material, and they can recover fully and quickly. 

When I was 16, I sprained my ankle playing soccer.  A sprain is when the ligament (bone to bone connection) becomes slightly torn or snaps from a sudden over-extension.  I had a slight tear, and the trainer said it was a "bad sprain".  This bad sprain took about 3-4 weeks to fully heal, during which time I was doing strengthening exercises and keeping it wrapped.  My point here is that it took me about the same time to heal from a slight ligament tear as it took for a woman to heal from a "slight" muscle tear, bone removal, and foreign object insertion.  Amazing. #health