Anterior knee pain refers to pain or ache towards the front of the knee possibly just behind the patella (kneecap). Often patients report their pain being aggravated by walking on stairs, prolonged sitting with a bent knee, squatting, running or jumping activities.  The thigh muscles may feel weak and you may have episodes of giving way, especially when walking down stairs. You may hear a cracking or feel a grating sensation behind the kneecap when moving the knee. Occasionally swelling may be present towards the front of your knee.