Downsides
- Invasive surgery can cause more harm than good - and should be elected with care.
Examples
- An artificial knee may get infected, leading to pus discharge, swelling and pain. Immune system cells have a harder time getting there and cleaning up.
- Myopes considering refractive surgery are advised that surgically correcting their nearsightedness may actually be a disadvantage after the age of 40 when the eyes become presbyopic and lose their ability to accommodate or change focus because they will then need to use glasses for reading. [Wikipedia article on Presbyopia]