Prevalence of neurocognitive disorders five years after elective orthopaedic surgery: a lesson for informed consent

Elective orthopaedic surgery comprises a significant amount of the UK NHS elective workload. With an ageing population, the demand for these services is expected to increase [1]. A cohort study of patients aged > 60 y undergoing elective orthopaedic surgery showed that more than half of all patients had some form of neurocognitive disorder five years after surgery, and this was major in 16.8% [2]. This is higher than the population prevalence of 6.8%, suggesting that anaesthesia and surgery may contribute to cognitive decline. These findings indicate that a considerable proportion of patients experience cognitive decline within five years of undergoing what is, typically, non-life-threatening or non-essential surgery. It is unlikely that we are counselling our patients adequately pre-operatively about this significant risk of morbidity. Consent in anaesthesia is a multifaceted and broad subject. The Association of Anaesthetists' 2017 guidelines recommend informing patients about common components of anaesthetic techniques, procedure-specific risks and common or significant adverse effects [3]. Ultimately, it is the responsibility of the clinician to decide what information is most relevant for each individual patient. In an editorial, Meek discusses the complexity of consent in the context of data from the 7th National Audit Project, which explored the incidence of potentially serious complications from anaesthesia [4]. The project captured extensive UK data, providing valuable information on complication rates [5]. However, interpreting the data and using them appropriately is where the challenges lie. The landmark Montgomery vs. Lanarkshire Health Board case in 2015 stressed the necessity of informed consent. The ruling clearly has a considerable impact on the way anaesthetists approach the consent process. The exhaustive list of anaesthesia risks, combined with the limited time often available for pre-operative discussions, makes it challenging to cover all potential risks in depth. Patients are also more likely to agree with the anaesthetist on the morning of surgery, feeling committed to the procedure despite possible risks [6]. The study by Atkins et al. highlights the importance of informed consent for anaesthesia, indicating that the risk of cognitive decline may outweigh the risks of the surgery in some cases [2]. Pre-operative clinics and assessments should integrate these findings, allowing patients to consider their options as early as possible. The Association of Anaesthetists is currently reviewing its guidelines on consent and an updated version is forthcoming.