Chondromalacia patella is a symptom complex characterized by aching pain behind the knee cap, retropatella tenderness that is aggravated by the stair climbing. Malalignment is an important factor causing chondromalacia patella. And to recognize it, is important in the diagnosis and treatment. We studied 3 parameters in the chondromalacic knee and nonchondromalacic knee and the following results was obtained. l. In nonchondromalacic knee, the sulcus angle is 141° 7′ and the congruence angle is −5° 1′ 2. In chonduomalacic knee the sulcus sagle is 139° 2′ and the congruence angle is +5° 3′ 3. In the group with abnormal congruence angle, there was much degenerative changes in the patellofemaral joint. So, it can be inferred that chondromalacia is a precursor of the osteoarthritis and the patient with abnormal congruence angle should be treated actively at the early stage if the conservative treatment had failed.