Fascia iliaca block for hip replacement – adjuvants and ethics

We commend Kearns et al. for their compelling study demonstrating non-inferiority of spinal morphine to fasica iliaca block (FIB) 1. We would like to invite the authors to comment on some further questions we have about this paper. Firstly, non-steroidal anti-inflammatory drugs (NSAIDs) are well known to be opioid-sparing, reducing the consumption of morphine by 30–50% 2. Do the authors have data on any difference between treatment groups pre- and postoperatively in NSAID consumption? Secondly, the authors reported a non-significant (p = 0.146) difference in pre-operative paracetamol consumption between treatment groups. Given that pain is a prominent feature prompting hip arthroplasty, could the authors comment on whether relative changes in pain scores might have been more appropriately reported than absolute pain scores? Finally, the authors suggest that a fascia iliaca block has a low complication rate, justifying the use of sham fascia iliaca blocks. However, in their study there was one incidence of temporary femoral nerve palsy (1 in 54). The sensory, motor and/or functional effects are not described, but this complication is important in a group of patients where a key aim of the surgical intervention is ambulation. Given that FIB does not offer any analgesic advantage (or perhaps even any analgesia 4) over spinal morphine for hip arthroplasties, do the authors consider FIB to be too risky for hip patients? Also, if there is risk but no clear benefit of fascia iliaca for hip arthroplasty, do the authors think it was justified to use sham fascia iliaca blocks in this study?