A joint effusion is present. There is extensive thickening and contrast enhancement of the synovium in the joint and its recesses, extending into the gastrocnemius-semimembranosus bursa as well - features of synovitis.
Articular cartilage is markedly thinned in the medial compartment.
Recent erosions are visible in the medial tibial plateau and lateral femoral condyle, with enhancing synovium within them.
There are subchondral changes in the posterior part of the lateral femoral condyle and in the peripheral medial tibial plateau, being a predictor for future erosive changes.
Additionaly, decreased volume and slightly irregular margins of the PHMM are seen, in keeping with chronic degenerative changes associated most likely with medial compartment cartilage loss.