Background: Recent randomized, controlled trials performed at two years postoperatively have shown that a primary total hip replacement is superior to internal fixation for the treatment of a displaced femoral neck fracture in a relatively healthy, mentally competent, elderly patient. The primary aim of the present study was to evaluate the outcomes at four years. Methods: One hundred and two patients (mean age, eighty years) who had an acute displaced femoral neck fracture were randomly allocated to be treated with total hip replacement or internal fixation. The inclusion criteria were an age of at least seventy years, absence of severe cognitive dysfunction, an independent living status, and the ability to walk independently. The main outcome measurements were hip complications, reoperations, hip function, and health-related quality of life. Results: The mortality rate was 25% in both groups. At the forty-eight-month follow-up evaluation, the rate of hip complications was 4% in the patients treated with total hip replacement and 42% in those treated with internal fixation (p < 0.001) and the reoperation rates were 4% and 47%, respectively (p < 0.001). The arthroplasty group had no additional hip complications or reoperations between the twenty-four and forty-eight-month follow-up visits. In the fixation group, the percentage of hip complications increased from 36% to 42% and the percentage of reoperations increased from 42% to 47% during the same period. The hip function was significantly better and the decline in health-related quality of life was less pronounced in the arthroplasty group than it was in the fixation group at the four, twelve, and twenty-four-month follow-up evaluations. Ninety-seven percent of the patients in the arthroplasty group and 57% of the patients in the fixation group who were available for follow-up at forty-eight months had no hip complications (p < 0.001). Conclusions: Compared with internal fixation, primary total hip replacement provides a better outcome for mentally competent elderly patients with a displaced femoral neck fracture. The complication and reoperation rates were significantly lower and hip function and health-related quality of life were at least as good at four years after the surgery.
