Conversation: The conversation between human and AI assistant.
[|Human|] My 16 year old son hurt his knee in football a few weeks ago, it instantly swelled, there is a hard spot in the middle with fluid around it and feels mushy, he was able to rub the knot down a week ago, however, he came home this evening and its bigger and he cant put any pressure on it, any suggestions?
[|AI|]  Hello, The most frequent and probable problem of the knee injury with a mechanism and signs like you are describing is anterior cruciate ligament tear. Anterior cruciate ligament is the ligament that links the tibia bone and femur bone in the knee. When it is torn, the knee swells up immediately, and you cannot continue the game. It causes the knee to "give away" often. If that is the case I would recommend doing an MRI of the knee and consult an orthopedic surgeon for possible treatment. The second option is a fracture of the bones around the knee that usually happen with a more high energy mechanism such as fall from height or car accident. Third option might be meniscus tear. Usually, the swelling of the knee here is not immediately like anterior cruciate ligament tear right away, but later in the evening or next morning. Again here an MRI of the knee would diagnose the problem and orthopedic consult is needed. Hope I have answered your query. Let me know if I can assist you further.