What are the causes for AVN?
Toxic (steroids, alcohol, immuosuppressants, NSAIDs); Traumatic (radiotherapy, idiopathic, fractures, burns); Inflammatory (RA, SLE, scleroderma, infection, pancreatitis); Metabolic/endocrine (pregnancy, diabetes, Cushing sydrome, gout); Haemopoietic disorders (haemoglobinopathies, polycythaemia, Gaucher disease, haemophilia); Thrombotic/embolic (dysbaric osteonecrosis, arteritis)
There is flattening of the left femoral head indicating cortical collapse. Appearances are typical for avascular necrosis.