Presentation
Knee pain and large swelling at the back of the knee and posterior upper leg. No history of trauma
Patient Data













Moderate intra-articular joint effusion with large medial popliteal cyst (Baker's cyst).
Diffuse thickening of the synovial lining of the knee joint more at supra-patellar recess.
Small osteochondral ulcers and erosions involving medial tibiofemoral condyles and lateral tibial condylar and patellar articular surfaces.
Rather thickened outline of the ACL with intra-substance bands of altered signal intensity suggesting its mucoid degeneration.
Markedly attenuated both menisci (involving body and horns) with fraying edges and intra-substance signal alteration.
Small left femoral condyle patchy subchondral marrow oedema eliciting bright STIR signal.
Multiple popliteal fossae rounded and oblong-shaped lymph nodes likely reactive.
Case Discussion
This case presents features of both OA and RA, including mild synovitis, joint effusion, cartilage loss as well as a large Baker's cyst.
Serological results revealed positive rheumatoid factor (RF) and anti-CCP as well as elevated ESR and CRP.
Findings are suggestive of mixed knee osteoarthritis and rheumatoid arthritis (RA).