19-year-old male patient with increased right knee pain and swelling. Known OCD lesion at the medial femoral condyle. Assess for loose body. MENISCI: The medial meniscus and lateral meniscus are intact.ARTICULAR CARTILAGE AND BONE: Again seen is a large ovoid focus of subchondral marrow signal abnormality within the medial femoral condyle consistent with a known osteochondral defect. The lesion is low signal intensity on T1-weighted images and heterogeneous on T2 weighted images. Extensive subchondral cyst formation is noted within this region along with bone marrow edema surrounding the defect within the posterior medial femoral condyle. The defect is similar in size to the prior examination measuring approximately 3 cm in the transverse dimension and 2.4 cm in craniocaudal dimension. The underlying cartilage appears degenerated though no intervening T2 signal is identified to suggest instability. There is a new crescentic region of signal abnormality within the anteromedial aspect of the medial femoral condyle consistent with an osteochondral defect. This defect measures approximately 1.3 cm in the AP dimension, 1.2 cm in the transverse dimension, and has a depth of approximately 0.9 cm. The defect itself demonstrates increased T2 signal though there is no intervening T2 signal to suggest instability. The underlying cartilage is degenerated without full-thickness defect.LIGAMENTS: The collateral and cruciate ligaments are intact. EXTENSOR MECHANISM: The extensor mechanism is intact.ADDITIONAL
1. New osteochondral defect with the anterior aspect of the medial femoral condyle. Similar appearance of an existing osteochondral defect with the posterior medial femoral condyle.2. Large Baker's cyst. No definite loose body.