[Post-surgery cognitive disorders: prevention, diagnosis and treatment strategies].

Hip fracture is an important step in the autonomy evolution in elderly. As gait is particularly jeopardised after such a traumatism, cognition may also be acutely impaired. Elderly post-surgery delirium is frequent, but chronic progression of cognitive impairment and dementia may occur. The concept of cognitive reserve is crucial for understanding risk factors of post-surgery delirium in elderly. The more the cognitive reserve is decreased before such a traumatism, the higher the delirium and dementia progression risk is. A neurodegenerative disease such as Alzheimer's disease may be clinically silent prior the traumatic event, and may decompensate soon after as the cognitive reserve is not sufficient anymore. Dementia may then lead to progressive autonomy loss. A systematic interdisciplinary approach is needed to prevent frail patients from delirium, and to early cure it to decrease the risk of long-term autonomy loss.