Preoperative nerve blocks for hip fracture patients: A pilot randomized trial

To determine the: 1) impact of pre-operative femoral nerve block(PreopFNB) on: a) pain; b) opioid use; and c) early post-operative mobilization relative to usual care(CONTROL) and 2) feasibility of a definitive randomized clinical trial(RCT).

This pilot RCT, performed in a Canadian tertiary center, compared PreopFNB to CONTROL in 73 participants aged ≥65 years, who a) were ambulatory pre-hip fracture, b) had Mini Mental Status Examination(MMSE) score ≥13 and c) provided consent(direct/proxy). Participants were randomized to PreopFNB or CONTROL using 2 PreopFNB:1 CONTROL(48 PreopFNB:25 CONTROL) allocation. Pain, opioid use and early post-operative mobilization were compared between groups. Inclusion of those with cognitive impairment and PFNB treatment fidelity were also assessed.

The PreopFNB group was slightly older than CONTROL(mean ±SD: 79.9 ± 8.9 versus 76.8 ± 9.0; p = 0.15) with more males(21[42%] versus 5[22%]; p = 0.04). The overall mean MMSE score was ≥24. Mean pain scores were not significantly different between groups at rest(p = 0.17), with activity(p = 0.21) or non-verbal assessment(p = 0.79). Opioid use(oral morphine equivalents) was non-significantly higher and more variable in CONTROL than PreopFNB pre-operatively(Median [25,75 quartiles] 13.1[0,398] versus 7.5[0,125]) and post-operatively(15.0[0,950] versus 10.0[0,260])(p = 0.28). On day 1 post-operative, 40(87%) PFNB and 17(71%) CONTROL participants mobilized(p = 0.10).

We found similar reported pain between groups. Although not significant, opioid use was higher and more variable in CONTROL and more PreopFNB patients mobilized day 1 post-operatively. Participants with cognitive impairment were not frequently enrolled. With modification, a definitive RCT is feasible and would inform pain management after hip fracture.