<prompt> The most common site of fracture neck of the femur that causes avascular necrosis is -Sub-capitalIntertrochantericTrans-cervicalBasal  <response>: The more proximal the location of a femoral neck fracture, the more likely there is to be nonunion andor AVN. Musculoskeletal traumaThus non-union and AVN will be most common in subcapital fracture and least in basicervical fracture. 