Presentation
Knee swelling for a few days, after a fall, unclear mechanism of trauma.
Patient Data
Lateral dislocation of patella, joint effusion and laxity of the patellar ligament and quadriceps tendon. There are a few small loose bone fragments adjacent to the patella. The presence of pnsumoartrosis without a penetrating trauma is concerning for infection, particularly considering the age group and the unclear trauma history and mechanism.
Case Discussion
The features are suggestive of a traumatic patellar lateral dislocation. Pneumarthoris without an obvious break in the skin and, in the setting of this unclear trauma history a few days ago in an elderly patient, is concerning for associated septic arthritis.