Between the smooth gliding surfaces and the shapes of the articulating joints there is very little inherent stability in the knee. As a result, there should be no surprise when, after an activity that you’ve no doubt performed hundreds of times before without incident, you sit staring in utter agony at your knee wondering what in the world happened. In such situations, however, it may be useful to know some of the most common knee injuries; or, just what the heck should you do now?!