Case scenario: Patient presents for recheck of knee pain in the clinic today. Was initially seen in the ER over the weekend by same physician for this knee injury. Slipped on the ice and his foot went under bumper of car hitting his knee. Aspirated the knee joint today. Diagnosis of knee pain. What is the correct diagnosis codes for this visit. If you code knee pain 719..46 and the E codes, insurance will not recognize as an injury because have not used an 800 or 900 code. Insurance companies generally look at the first diagnosis code and often times pay 100% on accidents. Can we code knee injury 959.7, then knee pain 719.46, then the E codes? Please advise. Thanks.