If the tests did not show any evidence of infection, perhaps the infection was not present when you were initially admitted and only happened after you had been in the hospital a while. As I understand it, what happened first was that you fell and injured it. At some point after you were admitted a needle was put into the knee to do testing to check for infection. If it did not find it - and it almost certainly would have - the infection was not there at the time the test was done.
I realize you will never be convinced, though. Have you ever actually sat down with any of the doctors who took care of you and asked for clarification of the course of events?
By the way, you cannot diagnose a knee infection with MRI. MRI cannot identify staph. You have to have a culture done to do that.
https://www.healthline.com/health/ba...t-inflammation
"Bacterial joint inflammation is a serious and painful infection in a joint. It’s also known as bacterial or septic arthritis. Bacteria can get into your joint and cause rapid cartilage deterioration and bone damage. This can lead to significant pain, swelling, redness, and loss of movement."
"The following medical tests can help them make a diagnosis:
- blood tests to detect the presence of harmful bacteria
- joint X-ray to assess the extent of joint and cartilage damage
- joint fluid sampling to determine the type of bacterial infection"
Note that MRI is not on that list.
On the other hand, the unfortunate woman in your link was obviously mismanaged.