Reader Question - What To Do When My Doctor Is Gaslighting Me?

I got the following question from reader Kyrie:

I started having pain in my knee after I jumped out of a truck and twisted it. I went to my regular doctor and he referred me to an orthopedist. He (the orthopedist) told me that the only thing that could possibly help was to lose weight. I asked the question that I learned from you “what would you recommend for a thin patient in this situation?”  The orthopedist said “I don’t have to talk to thin patients about knee pain.” Obviously that’s a complete lie, but what can I do as a patient when a doctor just says something like that?