Medial plica syndrome is usually a rare cause of anterior knee pain, but in adolescent athletes it is more common. A prospective investigation of clinical criteria for the diagnosis of medial plica syndrome was carried out. Investigating the stress test for the diagnosis of medial plica syndrome, we used active extension as a kick test and flexion to test blocking of swinging of the shank. The aim of this investigation was to examine these two new tests. The tests we used improved the accuracy of the clinical examination and allowed diagnosis of the symptomatic medial plica.