Local anaesthetic nerve blocks for people with a hip fracture

Background: Peripheral nerve blocks consist of an injection of local anaesthetics close to the nerves to transiently block pain transmission to the brain. This review examined evidence from randomized controlled trials that evaluated the use of peripheral nerve blocks to manage pain for people with a hip fracture.

Search dates: This is an update of a previously published review. We updated the search in August 2016.

Study characteristics: We included 31 trials (1760 adult participants: 897 randomized to peripheral nerve blocks and 863 to no regional blockade) performed in various countries and published between 1980 and 2016.

Study funding sources: Trials were funded by a charitable organization (n = 3), by a governmental organization (n = 1) or by departmental resources (n = 5), or did not specify the source of funding.

Key results: Compared with other modes of analgesia, peripheral nerve blocks used to treat hip fracture pain reduce pain on movement better within 30 minutes (equivalent to a difference of -3.4 on a scale from 0 to 10 between the two analgesic regimens). The risk of pneumonia is also reduced when peripheral nerve blocks are used to treat hip fracture pain. For every 7 people with a hip fracture, one less person will suffer from pneumonia. Studies noted no major complications related to peripheral nerve blocks and reported reduced time to first mobilization after hip fracture surgery (approximately 11 hours earlier). We did not identify enough trial participants to determine if regional blockade makes a difference in terms of acute confusion, myocardial ischaemia and death within six months after surgery. Peripheral nerve block given as a single injection led to reduced cost of analgesic drugs.

Quality of evidence: We rated the quality of evidence as high for reduction of pain on movement within 30 minutes, and as moderate for pneumonia, time to first mobilization and costs of analgesic drugs. We would need more information before we could draw final conclusions on effects of peripheral nerve blocks on the risk of acute confusional state, myocardial ischaemia and mortality.

Authors' conclusions: 

High-quality evidence shows that regional blockade reduces pain on movement within 30 minutes after block placement. Moderate-quality evidence shows reduced risk for pneumonia, decreased time to first mobilization and cost reduction of the analgesic regimen (single shot blocks).

Read the full abstract...
Background: 

Various nerve blocks with local anaesthetic agents have been used to reduce pain after hip fracture and subsequent surgery. This review was published originally in 1999 and was updated in 2001, 2002, 2009 and 2017.

Objectives: 

This review focuses on the use of peripheral nerves blocks as preoperative analgesia, as postoperative analgesia or as a supplement to general anaesthesia for hip fracture surgery. We undertook the update to look for new studies and to update the methods to reflect Cochrane standards.

Search strategy: 

For the updated review, we searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8), MEDLINE (Ovid SP, 1966 to August week 1 2016), Embase (Ovid SP, 1988 to 2016 August week 1) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO, 1982 to August week 1 2016), as well as trial registers and reference lists of relevant articles.

Selection criteria: 

We included randomized controlled trials (RCTs) involving use of nerve blocks as part of the care provided for adults aged 16 years and older with hip fracture.

Data collection and analysis: 

Two review authors independently assessed new trials for inclusion, determined trial quality using the Cochrane tool and extracted data. When appropriate, we pooled results of outcome measures. We rated the quality of evidence according to the GRADE Working Group approach.

Main results: 

We included 31 trials (1760 participants; 897 randomized to peripheral nerve blocks and 863 to no regional blockade). Results of eight trials with 373 participants show that peripheral nerve blocks reduced pain on movement within 30 minutes of block placement (standardized mean difference (SMD) -1.41, 95% confidence interval (CI) -2.14 to -0.67; equivalent to -3.4 on a scale from 0 to 10; I2 = 90%; high quality of evidence). Effect size was proportionate to the concentration of local anaesthetic used (P < 0.00001). Based on seven trials with 676 participants, we did not find a difference in the risk of acute confusional state (risk ratio (RR) 0.69, 95% CI 0.38 to 1.27; I2 = 48%; very low quality of evidence). Three trials with 131 participants reported decreased risk for pneumonia (RR 0.41, 95% CI 0.19 to 0.89; I2 = 3%; number needed to treat for an additional beneficial outcome (NNTB) 7, 95% CI 5 to 72; moderate quality of evidence). We did not find a difference in risk of myocardial ischaemia or death within six months, but the number of participants included was well below the optimal information size for these two outcomes. Two trials with 155 participants reported that peripheral nerve blocks also reduced time to first mobilization after surgery (mean difference -11.25 hours, 95% CI -14.34 to -8.15 hours; I2 = 52%; moderate quality of evidence). One trial with 75 participants indicated that the cost of analgesic drugs was lower when they were given as a single shot block (SMD -3.48, 95% CI -4.23 to -2.74; moderate quality of evidence).

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