The kneecap is also known as the patella. A dislocated kneecap is not uncommon, especially among athletes. Treatment, however, depends on the severity of the injury. Some kneecaps will relocate themselves. On the other hand, others need the help of a physician or knee specialist.
When your knee will not bend, it is a “locked knee.” The inability to straighten your knee can be painful. It can hurt to sit, stand, and step up. To relieve pain, you need to identify the cause.
An ACL (anterior cruciate ligament) injury commonly puts people on the bench. In fact, the pain is sharp and sudden and can limit what you do.