Hello Chris,

I am not an expert physio, but the presentation you gave us seems to be pretty serious.
Would be interesting to know the exact degree of lesion on the structures you mentioned, but my personal understanding of the injury you had sounds quite nasty.
If the ACL is fully ruptured then you need a surgical operation, and same applies to a 2/3 degree sprain of the MCL and ACL. If your menisci were to be removed than you would lose a great biomechanical advantage on your knee for what concern joint congruity and weight dissipation. (without menisci our the force passing through the tibial plateau is 5 times greater, so you can understand that putting even more weight on your knee is not the best thing to do)
I am puzzled that your surgeon suggested that, but it is true as well that surely he/she may have lot of experience and surely a better understanding of the your case.

Wish you all the best