What is the subtype of dementia in patients with fragility hip fracture?

Cognitive function is an important factor that affects functional recovery after hip fracture (HipFx) surgery. The literature on the pathophysiology of dementia in HipFx patients is scarce. We performed a differential diagnosis of dementia in HipFx patients using clinical and brain MRI findings. This is a prospective study in which brain MRI was evaluated for patients with HipFx for research purposes. One-hundred-and-five HipFx patients (85 females and 20 males) who underwent surgery and were subsequently able to undergo brain MRI at our hospital were evaluated. The mean age was 84 years. The presence of dementia was determined based on clinical findings and whether the patient meets its diagnostic criteria according to the International Classification of Diseases 10th Edition (ICD-10). The differential diagnosis of dementia was made based on brain MRI findings and the dementia diagnostic flow chart published in the Clinical Practice Guideline for Dementia 2017 (Japanese Society of Neurology). The Voxel-based Specific Regional Analysis System for Alzheimer's Disease (VSRAD) advance 2 diagnostic software was used to evaluate atrophy of the para-hippocampal gyrus. Fifty-six (53%) patients were clinically diagnosed with dementia according to the ICD-10 criteria. The MRI findings were diverse: Alzheimer's disease (AD)-type, asymptomatic multiple ischemic cerebral lesions, past symptomatic cerebral infarction or cerebral hemorrhage, Binswanger's disease (BW)-type, chronic subdural hematoma, disproportionately enlarged subarachnoidal hydrocephalus (DESH), and their combinations thereof. A combination of MRI and clinical findings of dementia patients demonstrated the following distribution of dementia subtypes: AD (n = 20), vascular dementia (n = 33), AD and BW vascular dementia (n = 3). This study revealed that the brain MRI findings of HipFx patients were diverse. Although vascular dementia is found to be common in this particular population, this could be an incidental finding. Further study is warranted to clarify the specificity of our findings by increasing the number of patients, setting the control, and investigating whether dementia subtypes affect postoperative gait acquisition and fall risk.