@Prosper , I will accept that surmising a knee injury (vs other soft tissues) is jumping to conclusions. I will propose that hearing/feeling a pop indicates something fairly serious has happened.
My evidence of poor diagnosis of knee injuries by GPs is anecdotal, but it is based on a sample size of around 5. In conversations about knee injuries, several other people have had similar experiences where their GP missed it. I have never had anyone say, "oh no, in my case my GP got it right."
I guess maybe we should score my knees as one-out-of-two. My first knee was the experience I described. For my second knee (a different year and a different doctor), the diagnosis was a) its probably not a bone but we will xray to be sure, and b) you have clearly done
something to your knee, and should see an ortho.
Of course, the first knee was looked at months later after everything had resolved except an intermittent instability.
The bottom line still stands: if you know or suspect you have done something to a joint, see an orthopedic doctor.