What Causes Pain In The Knee After A Car Accident?

hi, i had an car accident two months ago, i hurt my knee, under my steering wheel there is a metal rod i think i hit my knee on this, the doctors have told i have not broken any thing but the pain is still their, i can not bend my knee for long and if i do, when i stretch it it make a noise and it hurts. can u please tell me what is wrong