The effect of suprainguinal fascia iliaca blocks on morphine use after total hip arthroplasty: a retrospective cohort study

Background: Good pain control after total hip arthroplasty improves patient outcomes. Fascia iliaca blocks are used as part of multimodal pain management. Objectives: We compared patient-controlled intravenous ( PCIA) morphine use between patients with preoperatively placed suprainguinal fascia iliaca compartment block (SFICB), using 40 ml ropivacaine 0.375%, and a control group (NB). Design and setting: Retrospective, single-centre cohort study. Methods: A database of the Imeldaziekenhuis in Bonheiden, Belgium was analysed. This database contained data of total hip arthroplasties performed between April 29 2019 and May 7 2021. Inclusion criteria were age > 18 years and undergoing an elective total hip arthroplasty. The exclusion criterium was incomplete data registration. 277 patients were included in the study, 203 patients in the SFICB group and 74 in the NB group. A retrospective comparison between these two groups was performed. Main outcome measures: The primary endpoint was PCIA morphine use at 24 hours. Secondary endpoints were PCIA morphine use between 24 and 48 hours, Numeric Rating Scale pain scores, peroperative sufentanil use, postoperative piritramide consumption and nausea. Results: The median dose of PCIA morphine at 24 hours was 5 [ 2 to 9] mg in the SFICB group compared to 9.5 [5 to 15.75] mg in the NB group (P=0.000034). Lower pain scores at 48 hours (P=0.0003) and peroperative sufentanil consumption (P=0.015) were reported in the SFICB group. The median NRS pain score (P=0.02) and intravenous piritramide consumption ( P= 0.014) on the recovery ward were significantly higher in the SFICB group than in the NB group. No difference was reported for PCIA morphine use between 24 and 48 hours, pain score at 24 hours and nausea. Conclusions: Preoperative suprainguinal fascia iliaca block leads to less PCIA morphine consumption the first 24 hours, lower NRS pain scores at 48 hours and lower peroperative opioid need for total hip arthroplasty.