The lateral knee x-ray shows a large effusion in the knee joint. This finding alludes to the possibility of a fracture in the knee.
The most obvious finding on the frontal view is a small fragment of bone in the superolateral aspect of patella. This is not a fracture, but a developmental variant called bipartite patella.
There is a fracture of the lateral tibial plateau visible on the frontal view which is very subtle finding.
Bipartite patella is a developmental variant seen in about 2-3 % of the general population and is often an incidental finding on knee x-rays. It is bilateral in about 50%. It is usually seen as a well corticated fragment of patella in the superolateral pole.
Further reading https://www.orthobullets.com/pediatrics/4049/bipartite-patella