16-year-old female with knee pain. MENISCI: The medial and lateral menisci are normal.ARTICULAR CARTILAGE AND BONE: There is a bipartite patella and a contusion is present within the patellar accessory ossification center. The bones are otherwise intact. The articular cartilage is normal.LIGAMENTS: The medial retinaculum demonstrates a somewhat wavy contour with mild surrounding edema near its insertion on the patella, which suggests a partial tear. The cruciate and collateral ligaments are intact.EXTENSOR MECHANISM: The quadriceps and patellar tendons are normal. ADDITIONAL
Probable partial tear of the medial retinaculum and contusion of the patellar accessory ossification center likely reflects a prior patellar dislocation. There is evidence of patellar instability given findings suggestive of patella alta and trochlear dysplasia. However, the patella is currently in anatomic alignment. 