1)      Persistent localized pain (X-ray to exclude osteosarcoma)

2)      Persistent localized swelling (X-ray to exclude osteosarcoma)

3)      Night pain (severe OA, inflammatory arthritis, tumors, infection, crystals)

4)      Marked morning stiffness – more than 30 mins (inflammatory arthritis, rheumatoid arthritis )

5)      Arthritis of the knee following a sore throat, tachycardia (exclude acute rheumatic fever)

6)      Sudden onset knee pain and swelling without preceding trauma in immunocompromised patients with cancer, diabetes, alcoholism, AIDS, corticosteroid therapy (Septic arthritis)

7)      Painful swelling of the knee within 2 hrs of knee trauma (haemarthrosis with ligamental ruptures)

8)      Adolescent with knee pain, knee clicks, knee giving-way, inability to fully extend the knee, positive Wilson’surgical technique sign – ie. Flex the knee to 90* and then internally rotate the tibia while extending the knee slowly (Osteochondritis Dissecans of the knee)