31-year-old male 2 weeks status post injury to the left knee while walking the dog. Presents with locking and catching on exam. The ACL feels stable. MENISCI: There is increased signal intensity within the posterior horn and body of the medial meniscus suggestive of mucoid degeneration, but we see no discrete tear. There is a small lobulated collection of fluid signal intensity between the lateral meniscus and IT band which may represent a small ganglion or parameniscal cyst, although we see no discrete meniscal tear.ARTICULAR CARTILAGE AND BONE: There is mild heterogeneity of the signal intensity of the articular cartilage of the lateral tibial plateau suggestive of mild degeneration and possibly a small cleft beneath the posterior horn of the lateral meniscus. The articular cartilage otherwise appears normal for age. There is mild edema-type signal intensity within the lateral tibial spine which is nonspecific.LIGAMENTS: There is thickening of the proximal fibers of the PCL as well as increased signal intensity within the mid fibers, indicating a mid-substance rupture. The ACL appears intact. The collateral ligaments appear intact. EXTENSOR MECHANISM: The extensor mechanism appears intact.ADDITIONAL
Midsubstance tear of the PCL and other findings as described above. We see no discrete meniscal tear.