How Should Knee Pain With Movement Problems And Crepitus Be Treated?

hello doctor im suffering from a knee problem which been sustaining for long.it happened out few months month back while playing football.i was caught up in the air and gt collided with an offender which i believe happened to twist my knee. i heard a crackling sound and i fell. i reached the hospital with an xray but it dint show any injuries. i was prescribed some drugs and i took them, but i still had troubles in bending the knee at the end,like we say attending the call of nature using the indian latrines. and this problem longed and i usually hear i crackling sound when the knee undergoes any stresses, it gives its way out. can u help me at the earliest.jaseen