60 year-old female with history of medial joint line tenderness. Evaluation of the proximal tibia is limited due to metal susceptibility artifact from intramedullary rod which is incompletely imaged on this study.MENISCI: There is attenuation of the body and posterior horn of the medial meniscus. In particular, there is very little meniscal tissue identified near the root. In the absence of prior meniscectomy, this represents a radial root tear with additional attritional tearing of the remaining posterior horn and body. Alternatively, these findings may be due to prior meniscectomy. There is linear signal abnormality within the posterior horn of the medial meniscus which extends to the articular surface. In absence of prior surgery, this represent a tear, although this also could simply represent residual degenerative signal from prior partial meniscectomy.ARTICULAR CARTILAGE AND BONE: There are severe degenerative changes of the articular cartilage of the medial tibial-femoral compartment with areas that are devoid of cartilage. There are small foci of signal abnormality in the underlying bone, likely degenerative in etiology. There are a few small foci of signal abnormality within the medial femoral condyle which could conceivably represent tiny regions of avascular necrosis, but this is equivocal. There is near full thickness articular cartilage degeneration of the lateral femoral condyle above the posterior horn of the lateral meniscus. There is also severe osteoarthritis of the patellofemoral joint with areas along the medial facet of the patella which are devoid of cartilage. There are tricompartmental osteophytes.LIGAMENTS: The fibers of the ACL are indistinct. The distal fibers of what may be the ACL extend to a focus of signal abnormality within the anterior aspect of the joint that we believe corresponds to an ossicle seen on recent radiographs. This constellation of findings may represent a chronic ACL avulsion injury from the tibial plateau. The PCL, MCL, and LCL are intact.EXTENSOR MECHANISM: The quadriceps tendon is intact. There is thickening of the medial aspect of the patellar tendon which may reflect tendinosis or scarring from prior surgery.ADDITIONAL
1.Severe osteoarthritic changes as described above.2.Small foci of signal abnormality within the medial femoral condyle may conceivably represent tiny foci of avascular necrosis, but this is equivocal.3.Postoperative changes as above.4.Medial meniscal abnormalities as described above which may reflect prior partial meniscectomy, but we cannot exclude the possibility of a tear.5.Possible chronic avulsion injury of the ACL off the tibial plateau.6.Thickening of the patellar tendon which may be postoperative or degenerative in etiology.