The central area of the articular surface shows irregular pitting with iron staining of the floor. The
depth of the erosions suggests that they extend to expose bone. At the periphery there are irregular
areas where the cartilage has been lost and around the articular surface there is haemosiderin
This young man had a Factor VIII of 2%. Over some 9 years he had had several episodes
of bleeding into the left knee joint with pain and limitation of movement and ultimately, at the age
of 21, the patella was removed.