Hello serena,
could it be those who developed neuropathy after knee surgery were already predisposed to neuropathy and without symptoms prior to their surgeries and the surgery trauma triggering the neuropathy?
The reason I am saying this and I don't know if it compares, is when I had a right middle trigger finger surgery and was doing very well with therapy after less than 2 weeks and suddenly I developed what no one would have known, Dupuytren's contacture, where the right middle and ring finger would close shut by scar tissue under the skin that turns into ropes and contracts. The surgeon who did both my carpal tunnel and Dupuytren's contarcture surgery at the same time told me that the contracture was triggered by the trigger finger surgery done three or 4 weeks prior to the second surgery. Believe it or not, I had a functional hand capacity test for 3 hours and the hand was deemed permanently damaged and disabled and I am right handed. the hand will not fully open or close and I can perform very small things with it. The numbness and pain in it can be hellish most days. That's on top of my neuropathy and cerviacal and lumbar radiculopathy.
Take care and keep smiling,
gus