The most common site of fracture neck of femur that cause Avascular necrosis is-

The more proximal the location of a femoral neck fracture, the more likely there is to be nonunion and/or AVN. *Thus non-union and AVN will be most common in subcapital fracture and least in basicervical fracture. M/c affects => Femoral Head M/c site => Anterolateral aspect (Being principal Wt. bearing poion) Incidence&;d/t t Steroid usage & Trauma AVN only occurs in FATTY MARROW, which contains a Sparse vascular supply. In contrast to Hematopoietic marrow which has a rich blood supply CAUSES * Trauma * Alcohol consumption * Coicosteroid intake * Gout and hyperuricemia * Hypercholesterolemia * Hypercoagulable states Hypercoisolism * Hyperlipidemia * Cushing disease * Hyperparathyroidism * Hemoglobinopathies * Intravascular coagulation (SCD;Hb S/C;Polycythemia) * Organ transplantation * Caisson disease * Pregnancy (Dysbaric osteonecrosis) * Congenital dislocation Hip * Pancreatitis * Ehlers-Danlos synd * Neoplasms * Heredity dysostosis * CRF * Legg-Calve-Pehes dis * Hemodialysis * Fabry disease * Cigarette smoking * Gaucher disease * Collagen Vascular dis * Giant cell aeritis * SLE * Thrombophlebitis * Idiopathic Ref: maheswari 9thed p.311