The influence of cognitive status on outcome and walking ability after hemiarthroplasty for femoral neck fracture: a prospective cohort study

INTRODUCTION: Femoral neck fracture (FNF) is a devastating injury with serious medical and social consequences. One-third of these patients have some degree of impaired cognitive status. Despite this, a high proportion of hip fracture trials exclude patients with cognitive impairment (CI). We aimed to evaluate whether moderate to severe CI could predict walking ability, quality of life, functional outcome, reoperations and mortality in elderly patients with displaced FNF treated with hemiarthroplasty (HA). METHODS: This cohort study included a consecutive series of 188 patients treated with HA for a displaced FNF. Patients were assessed for estimated preoperative and 1 year postoperatively with regard to walking ability, cognitive status, quality of life with EQ-5D and hip function with Harris hip score. RESULTS: There were 188 patients who met the inclusion criteria. A total of 130 patients were in the control group, and 58 were in the CI group. At 1-year follow-up, 31 patients (24%) had died in the control group and 22 patients (38%) had died in the cognitive impaired group. This difference in reoperation and mortality rate was statistically significant (log-rank test, p = 0.016). The CI had a significantly higher incidence of being non-walker (28 vs. 4%, OR 9.2, p = 0.001). The EQ-5D was higher in the control group, while the Harris hip score was comparable in the two groups. CONCLUSIONS: Moderate to severe CI was associated with a high incidence of non-walking ability, worse quality of life, high mortality and re-operation rate after femoral neck fractures treated with HA.