There are a huge number of causes of knee pain. Sometimes it occurs after a knee injury, but often the pain in the knee results from a slow build up over time rather than an obvious one-off event. Things might get swollen or worn, or problems develop due to muscle imbalance.
Please note: This section concentrates on pain that has developed gradually without a specific injury. There are other knee injuries caused by one off events such as a fall or sports activity, including treatment and recovery information.