Hello, From what you re told, sharp pain in the knee among with fever and a history of flu, I suspect that you may have chikungunya. Once bitten by a mosquito carrying the virus, the symptoms will begin to feel at 3 to 12 days afterward. The symptoms initially resemble flu symptoms. Symptoms of chikungunya: 1. High fever 2. Pain in the joints, especially on the neck and knee 3. Low back pain The other possibility is rheumatoid arthritis, which is an autoimmune condition, in which the immune system attacks its own joint which can affect almost every joint in the body, including the knee. Although, rheumatoid arthritis includes long-term (chronic) illness, but its severity tends to vary and may even come and go. Right now I suggest you to meet your local rheumatologist to get further evaluation, the tests that may be needed are: 1. Serological tests, such as enzyme-linked immunosorbent assays (ELISA), may confirm the presence of IgM and IgG anti-chikungunya antibodies. 2. Erythrocyte sedimentation rate (ESR, or sed rate) or C-reactive protein (CRP), which may indicate the presence of an inflammatory process in the body. 3. Other blood tests look for rheumatoid factor and anti-cyclic citrullinated peptide (anti-CCP) antibodies. Some tips for you: 1. Get enough rest to keep the knee from being pressed so that the injury can recover faster. 2. Compressing knees with ice. This step can reduce pain as well as inflammation. 3. Minimize movement of the knee 4. Put an injured foot in a higher position. An example is to put your feet on a pillow. This can help reduce swelling. 5. You can take Naproxen or Ibuprofen as a painkiller. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Nurul Falah