Local nerve blocks around the time of hip fracture surgery reduced pain on movement within 30 minutes of injection. People had less need for opioid pain-relief and were quicker to mobilise after surgery. Also, one case of pneumonia was prevented for every seven people given pain relief using a nerve block.
By injecting local anaesthetics close to the nerves to relieve pain after a hip fracture, it is hoped that the need for opioids can be reduced and people might recover more quickly. Nerve blocks are not standard in UK hospitals for this.
This updated Cochrane review identified 31 trials providing moderate to high-quality evidence. The benefits were small but could make a meaningful difference to the patient’s experience and outcomes.
This lends further support to guideline recommendations and the added evidence might increase the use of nerve blocks for hip fracture.
Why was this study needed?
Each year about 65,000 people in the UK fracture their hip, costing the NHS around £1 billion. Older adults are most susceptible to hip fracture. A third will die within one year, often as a result of associated illness. Opioid drugs are commonly used to manage the pain, but these can have serious adverse effects. The use of local nerve blocks may reduce the need for opioids before, during and after surgery. This may, in turn, improve outcomes for patients.
However, peripheral nerve blocks are not routinely used for people with hip fracture. The Royal College of Physicians reported in 2016 that only around half of UK hospitals were using local nerve blocks around the time of surgery. Considering this low rate, this updated Cochrane review aimed to re-evaluate the effects of peripheral nerve blocks for hip fracture.
What did this study do?
The review included 31 small randomised controlled trials assessing the use of peripheral nerve blocks in 1,760 adults having hip fracture surgery.
In 21 trials the blocks were given before surgery, four trials used them during surgery and five after surgery. The most common procedure was femoral nerve block. Blocks were by a single injection or a continuous or repeated infusion and were given for a duration ranging from 15 to 92 hours. Doses were equivalent to lidocaine five to 22.5mg/mL.
The main outcomes were pain, acute confusion and heart attack. The most common comparator was intravenous or intramuscular opioids.
Trials were published between 1980 and 2016, and five came from the UK. Potential sources of bias included staff being aware of the treatment allocated.
What did it find?
- People receiving peripheral nerve blocks had reduced pain scores on movement within 30 minutes of block placement (standardized mean difference [SMD] -1.41, 95% confidence interval [CI] -0.67 to -2.14; eight trials, 373 people). This is equivalent to scoring 3.4 points lower on a scale of 0 to 10. No differences were found in pain scores at later time points.
- Three moderate quality trials with 131 participants, showed a lower risk of pneumonia (relative risk 0.41, 95% CI 0.19 to 0.89). This means that for every seven people treated with a nerve block for hip fracture, one less person will contract pneumonia.
- Seven trials showed that peripheral nerve blocks reduced opioid use up to 24 hours after surgery (SMD -0.70, 95% CI -0.96 to -0.44). Results were consistent across individual studies, and for both single shots and continuous infusions.
- In two moderate quality trials with 155 participants, peripheral nerve blocks reduced time to mobilisation after surgery (mean difference -11.25 hours, 95% CI
-8.15 to -14.34 hours).
- Very evidence from seven trials found no effect on rates of acute confusion.
What does current guidance say on this issue?
The 2017 NICE guideline on the management of hip fracture says that nerve blocks should be considered before surgery if paracetamol and opioids do not provide sufficient pain relief, or to limit opioid dosage. They should also be considered intraoperatively for all patients undergoing surgery. NICE doesn’t make recommendations about the type of block to use.
NICE provides procedural guidance about performing ultrasound-guided regional nerve block to help ensure the block is properly placed.
What are the implications?
The findings suggest small benefits, but any improvements in pain relief and comfort are highly relevant for patients. Earlier mobilisation combined with less need for opioids and their associated risk of respiratory depression may have contributed to reduced risk of pneumonia.
The results of this review strengthen the case for the use of nerve blocks for patients with hip fracture in UK hospitals especially those at risk of poor mobility due to frailty or with pre-existing respiratory problems.
Citation and Funding
Guay J, Parker MJ, Griffiths R, Kopp S. Peripheral nerve blocks for hip fractures. Cochrane Database Syst Rev. 2017;5:CD001159.
NHS Choices. Hip fracture. London: Department of Health; 2016.
NICE. Hip fracture: management. CG124. London: National Institute for Health and Care Excellence; 2017.
NICE. Ultrasound-guided regional nerve block. IPG285. London: National Institute for Health and Care Excellence; 2009.
RCP. National Hip Fracture Database annual report 2016. London: Royal College of Physicians; 2016.
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