Is dual cup mobility better than hemiarthroplasty in patients with dementia and femoral neck fracture? A randomized controlled trial.

PURPOSE

Treatment of patients with dementia and hip fracture is challenging. Total hip arthroplasty (THA) with dual mobility cup (DMC) has been designed to reduce the rate of dislocation by increasing the stability of the implant. This study aimed to compare the dislocation rates of DMC THA with hemiarthroplasty (HA) in elderly patients with displaced femoral neck fracture (FNF) and a diagnosis of dementia.

METHODS

All patients with a displaced FNF and dementia diagnosis were prospectively randomized to hemiarthroplasty or THA with DMC treatment during a 2-year period. Finally, the outcomes of 30 patients in the HA group were compared with those of 30 patients in the DMC THA group. Dislocation rate at a minimum follow-up of 1 year was evaluated as the primary outcome. Reoperation rate, time to surgery, surgical time, length of hospital stay, and 30-day and 1-year mortality were also evaluated.

RESULTS

There was a significant difference regarding rates of dislocation in favor of THA with DMC and with regard to length of surgery (p = 0.04) in favor of bipolar HA. Dislocation occurred in five patients (16.6%) treated with bipolar HA and no one (0%) in patients treated with THA with DMC (p = 0.019). There was no difference with regard to the 30-day mortality, 1-year mortality, reoperations, and length of hospital stay between the two groups of patients.

DISCUSSION

THA with DMC seems to be a safe and reliable choice to reduce the rate of dislocation at 1 year in patients with dementia and FNF without a higher risk of mortality.