Ultrasound-guided peripheral nerve blocks for preoperative pain management in hip fractures: a systematic review

Systematic reviews associate peripheral nerve blocks based on anatomic landmarks or nerve stimulation with reduced pain and need for systemic analgesia in hip fracture patients. We aimed to investigate the effect of ultrasound-guided nerve blocks compared to nerve blocks without the use of ultrasound and to conventional analgesia for preoperative pain management in hip fractures. Five databases were searched until June 2021 to identify randomised controlled trials. Two independent authors extracted data and assessed risk of bias. Data was pooled for meta-analysis and quality of evidence was evaluated using Grades of Recommendation Assessment, Development and Evaluation (GRADE). Our search did not identify trials comparing ultrasound-guided nerve blocks to different block techniques without use of ultrasound. However, we included 12 trials (976 participants) comparing ultrasound-guided nerve blocks to conventional systemic analgesia. In favour of ultrasound, pain after block placement decreased with a mean difference of -2.35 (VAS 0 to 10); (p<0.001) 95% CI [–3.07 to –1.62]. In favour of ultrasound, preoperative analgesic usage of iv. morphine equivalents in milligram decreased with mean difference of –5.34 (p=0.003) 95% CI [–8.11 to –2.58]. Further, ultrasound-guided nerve blocks may be associated with a lower frequency of delirium, fewer serious adverse events and higher patient satisfaction. However, the quality of evidence was judged low or very low. In conclusion, no trials comparing ultrasound to other block techniques were found, thus not permitting conclusions on our primary aim. Despite low quality of evidence, ultrasound-guided blocks were associated with benefits compared to conventional systemic analgesia.