Pre-operative femoral nerve block for hip fracture-A systematic review with meta-analysis

Background Pre-operative pain management of hip fracture patients is complex. Femoral nerve block (FNB) is used for hip fractures to reduce pain and demand for systematic analgesia. The objective of the study was to systematically investigate the efficacy of single-shot FNB for hip fracture patients. Methods Five databases were searched from inception until 8 May 2019. We included randomized controlled trials (RCT's) assessing pain relief in patients with hip fractures. Intervention was pre-operative FNB compared to any systemic analgesic (eg opioids, non-steroidal anti-inflammatory drugs or paracetamol). Primary outcomes assessed were pre-operative pain and use of rescue analgesics. Secondary outcome was cognitive impairment. We present a bias assessment, a meta-analysis and a grading of certainty of evidence. Results We included five trials (n = 254), where participants received FNB 30 minutes or more prior to surgery; all were judged as having high risk of bias. All studies found significantly decreased pain scores at least once in the intervention group compared to the control group. Meta-analysis on the primary outcome of pain showed significance. Mean difference was -2.13 point (in cm) (CI:-3.53,-0.72) on visual analogue scale in the intervention group, but is judged low on certainty. Conclusions The quantity of evidence supporting pre-operative single-shot FNB for hip fractures is very low, and the certainty of evidence supporting pre-operative single-shot FNB for hip fractures is low. No studies using ultrasound guided technique were identified. Data on non-ultrasound guided FNB's suggest a decreased pain score compared to the use of systemic analgesia.