- Patient supine with leg straight
- Examiner applies anterior to posterior pressure over the patella
- Examiner gently oscillates the patella, palpating for motion
Patellar Ballottement Test
Increased motion or spongy joint feel: Intra-articular knee swelling
Normally the patella should move approximately 1 mm, in the presence of joint swelling the anterior to posterior motion will be increased as local edema raises the patella further off the femur. Trauma is the most common cause of joint effusion at the knee (internal derangement, ligament sprain or rupture, vascular damage, fracture).