65-year-old male with an acute knee injury presents with left knee pain and swelling. MENISCI: There is horizontally oriented signal within the posterior horn and body of the medial meniscus extending to the tibial articular surface indicating a horizontal tear. This tear extends through the peripheral fibers of the posterior horn of the medial meniscus and is associated with small parameniscal cysts, posteriorly. There is additional globular signal replacing much of the root of the medial meniscus which extends to the free edge of the meniscus likely representing mucoid degeneration and additional tearing. There is blunting of the free edge of the posterior horn of the lateral meniscus indicating degeneration/radial tearing. There is additional intrasubstance degeneration noted within the body of the lateral meniscus.ARTICULAR CARTILAGE AND BONE: There is superficial degeneration of the articular cartilage of the patella with small subchondral cysts noted inferiorly. There is focal degeneration of the articular cartilage of the medial facet of the femoral trochlea, inferiorly. There is heterogeneity of the articular cartilage of the medial femoral condyle posteriorly indicating mild degeneration. LIGAMENTS: The ACL appears intact. The proximal fibers of the PCL appears thickened with foci of increased signal intensity internally. This likely represents chronic degeneration with acute interstitial tearing considered less likely. The MCL and LCL appear intact.EXTENSOR MECHANISM: There is a tear of the quadriceps tendon and its patellar insertion. The tear involves predominantly the middle and posterior components of the tendon (tendons of the vastus musculature) with approximately 1 cm of retraction. The anterior fibers of the rectus femoris can be traced to the patella, although there is increased signal intensity within the rectus femoris fibers approximately 3 cm proximal to its insertion, suggesting partial thickness tearing. There is heterotopic ossification within the proximal patellar tendon indicating chronic tendinosis. The patellar tendon otherwise appears intact. ADDITIONAL
1. Insertional quadriceps tear as described above.2. Medial and lateral meniscus degeneration and tears as described above.3. Thickening and increased signal intensity of the proximal fibers of the PCL likely representing chronic degeneration rather than acute tearing.4. Small joint effusion and Baker's cyst.5. Cartilage degeneration and other findings as described above.