Two hundred and thirty-six patients with or without dementia who had sustained a hip fracture, either trochanteric or cervical, were randomized to receive a femoral nerve block (FNB) or conventional pain management; opioids were administered as required for both groups. The outcomes of interest included complications both pre- and post-operation, including delirium, length of hospital stay, cognitive status as per the Mini Mental State Examination, depression as per the Geriatric Depression Scale, morale as per the Philadelphia Geriatric Center Morale Scale, and pain on a Visual Analogue Scale. Subgroup analysis was conducted for patients with dementia. No significant differences were observed between the FNB and conventional treatment arms with respect to the incidence of complications, including delirium. In the subgroup analysis of patients with dementia, no significant differences in the incidence of complications were observed, with the exception of the incidence of diarrhea which was significantly lower in the FNB group. Furthermore, in patients with dementia who received FNB, a significantly lower number of complications were observed compared to patients with dementia in the control group.