Fixation of femoral neck fractures is associated with a higher incidence of complications than any other fracture. The rates of nonunion and avascular necrosis with open reduction and internal fixation continue to be unacceptably high. These complications are the main reason for resorting to primary endoprosthetic replacement of the femoral head in the presence of displaced fractures in elderly patients. However, with the increasing life span of the patients with these prostheses, late complications of endoprosthetic replacement of the femoral head are becoming significant. With these complications, it may be argued that the most cost-effective solution to the femoral neck fracture in the majority of patients is open reduction and internal fixation, with elective conversion, when necessary, to total hip arthroplasty in patients who have a complication. Because the literature does not contain a systematic review of reasons for failure of internal fixation, the authors will attempt to review the common means of failure of internal fixation in young and older patients in an attempt to better understand and prevent these complications.