Femoral neck fracture of three weeks old in a young adult should be best treated by one of the following -
Total hip replacement
Reduction of fracture and femoral osteotomy with head
Prosthetic replacement of femoral head
Reduction of fracture and multiple pin or screw fixation
Up to 3 weeks, treatment of choice for fracture femoral neck in a young patient is closed reduction and internal fixation by multiple screws.