Abstract
We performed a randomized feasibility trial to examine the impact of preoperative femoral nerve block (FNB) on elderly patients with hip fractures, including those with mild to moderate cognitive impairment. We evaluated the impact of preoperative FNB on the following outcomes within 5 days of surgical fixation: 1. Pain levels, 2. Total narcotic consumption, 3. Postoperative mobilization.
Randomized allocation of 73 patients in a 2:1 intervention:control ratio. To allow comparison between the 2 groups as well as sub- analysis of the intervention group to examine treatment fidelity (i.e. the ability to deliver the intervention as planned).
Inclusion criteria: Patient age≥ 65 years admitted with a low energy hip fracture, ambulatory preinjury, Mini Mental State Exam MMSE score≥13 (moderate dementia), Able to provide direct or proxy consent. Exclusion criteria: Admission ≥ 30 hours after injury, prior regular use of opiates. Potential participants were identified and either participants or proxy respondents provided signed informed consent. Participants allocated to the intervention group received a FNB administered by the UAH acute pain service (APS) within 20 hours of admission to hospital in addition to the usual care. Participants in the control group received usual care. Participants were followed for 5 days postoperatively with daily assessment of pain, narcotic consumption, delirium and mobility.
Main outcome measure: (1) Pain at rest and activity (2) Preoperative and postoperative opioid consumption, (3) Mobilization in POD#1.
Overall, 73 participants were enrolled (23 Control: 50 FNB). The FNB group was slightly older (mean [SD] 80.1 [8.7] vs. 76.2 [9.2], p=0.09) and had more males (21 [42%] vs. 5 [22%], p=0.09) than the Control group. The mean MMSE score for both groups was >24 (p=0.35 for group comparison), suggesting minimal cognitive impairment of participants. The FNB group reported significantly less pain at rest and activity than the control group over time (p < 0 .001 for both). Opioid consumption were non-significantly higher and more variable in the control group preoperatively (Median [25, 75 quartile] 10.6 [0, 398] vs 7.5 [0, 125], p=0.26) and postoperatively (13.1 [0, 950] vs 10 [0, 260], p=0.31). 41 (85%) of FNB participants mobilized on day 1 vs. 16 (73%) of control participants (p=0.21).
Preoperative FNB significantly reduced pain. Opioid consumption was not significantly different, but more variable in the control group. Although not significant, more FNB patients successfully mobilized on day 1 postoperatively. Participants with cognitive impairment were not enrolled due to difficulty in obtaining proxy consent. A definitive randomized trial would be feasible and add valuable information about pain management following hip fracture.
