Case Report #48: Hip Fracture

There are approximately 76,000 hip fractures each year in the UK and this is projected to increase as our population ages¹. Hip fractures are the most common reason for older people to require emergency surgery and have significant morbidity and mortality associated with them². Guidance from the Association of Anaesthetists emphasises the importance of timely surgery in these patients, stating that ‘surgery should be delayed [beyond 36hrs from fracture] only if the benefits of additional medical treatment outweigh the risks of delaying surgery’. One risk of delayed surgery is complications that arise from prolonged pain and immobility including post operative delirium³. Deciding who may benefit from a non-operative approach is not straightforward⁴.

So, this raises the question – in those whom surgery is delayed, either for medical or prognostic reasons, such as Mrs D, how can we best manage their pain to minimise suffering but also reduce the risk of post operative complications such as delirium? 

Firstly, we need to assess pain.

Pain assessment in the elderly, especially those with cognitive dysfunction, as is present in 30% of patients with hip fractures² can be challenging. Guidelines from 2018 advise that whilst subjective self-reported pain assessment is the most valid and reliable indicator of pain, it may be necessary to re-word our standard pain questioning to bypass the ‘stoicism’ present in many elderly patients. In patients with cognitive impairment Numerical Rating Scales or verbal descriptors can be reliably used. However, alternatives such as Pain in Advanced Dementia (PAINAD) and Doloplus-2 are required in severe cases. Many UK centres commonly use the Abbey Pain scale for this purpose⁵. 

Pain management in the elderly can also be challenging. It is important to consider the side effect profile and the impacts that aging and co-morbidity have on physiology often necessitating dose adjustment. Older adults’ ability to metabolise drugs will often be reduced due to changes in body composition, cardiovascular, renal and hepatic systems. Following the World Health Organisation (WHO) analgesic ladder: paracetamol is largely safe and no dose reduction is required unless the patient has a body weight less than 50kg. NSAIDs carry increased risks of gastrointestinal bleeding in this age group and have been linked with increased cardiovascular risks and worsening of renal impairment. Moderate pain can be treated with codeine, but variable metabolism may lead to inadequate analgesia and side effects such as constipation can be particularly significant in older adults and associated with cognitive dysfunction. Other weak opioids such as tramadol may be used but have a prolonged half-life in the older adult and can interact with other medications as well as causing hallucinations. Management of severe pain will usually require strong opioids in some format. These should be started ‘low and slow’ with side effects anticipated and mitigated (nausea, constipation, drowsiness, respiratory depression)⁶. In line with recent MHRA guidance regarding the use of prolonged-release opioids, only immediate-release opioids should be used for acute or perioperative pain⁷. 

Novel approaches to pain management are emerging and may offer an improved side effect profile to traditional systemic options. Lower limb regional blocks have been widely used in hip surgery as analgesic adjuncts. A variety of approaches have been described⁸ with Niu et al reporting a successful operation in a frail patient with PENG, lateral femoral cutaneous nerve, sacral plexus and paravertebral nerve blocks⁹.

Fascia iliaca blocks are regularly used at initial presentation with hip fracture. In patients where surgery is delayed (or not felt suitable), local anaesthetic infusions via nerve catheters can be helpful in managing severe pain without the side effects of systemic analgesia. The provision of these will likely depend on individual site anaesthetist skill mix, availability and ward capability to run continuous infusions.