35-year-old male with left knee pain. Evaluate patellar tendon instability. MENISCI: The medial and lateral menisci are morphologically normal.ARTICULAR CARTILAGE AND BONE: Note is made of a patella alta with an Insall-Savlati ratio of 1.9. The patellar tendon is intact and morphologically normal. The articular cartilage of the patella at the mid to inferior pole is markedly irregular with areas of full-thickness defects/intermediate signal intensity in the cartilage extending to the subchondral bone surface (for example series 601, image 13). There is hypoplasia of the trochlear groove which is abnormally flattened. Tibial tubercle to trochlear groove distance measures 9 mm, within normal limits.The articular cartilage of the femoral condyles and proximal tibia are morphologically normal. Bone marrow signal intensity is normal. There is no significant fluid within the knee joint.LIGAMENTS: The cruciate and collateral ligaments are morphologically normal.EXTENSOR MECHANISM: The extensor mechanism is intact and morphologically normal.ADDITIONAL
1. Patella alta as well as hypoplasia and abnormal flattening of the femoral trochlear groove.2. Patellar articular cartilage degeneration with areas of full-thickness defects extending to the subchondral bone surface.