What are the causes of avascular necrosis (AVN) of the femoral head?

Causes of avascular necrosis (AVN) of the femoral head

• Congenital dislocation of the hip
• Perthes' disease
• Trauma (subcapital fractures of the femur)
• Steroid therapy
• SLE
• Sickle cell anaemia
• Diabetes mellitus
• Alcohol abuse
• Gaucher's disease
• HIV inflection
• Caisson's disease 

Source:

• Rapid review of clinical medicine for MRCP part 2, 2nd Edition, by Sanjay Sharma and Rashmi Kaushal; Q-357
• Kumar and Clark's clinical medicine, 9th Edition; page 659
• Davidson's Principles and Practice of Medicine; 23rd Edition; page 1055