Comparison between supra-inguinal fascia iliaca and pericapsular nerve group blocks on postoperative pain and functional recovery after total hip arthroplasty: A noninferiority randomised clinical trial.

Background: Pain after a posterolateral approach for total hip arthroplasty (THA) may affect early functional recovery. Supra-inguinal fascia iliaca (SFIB) and pericapsular nerve group (PENG) blocks have been proposed as promising analgesia techniques.

Objectives: This trial was conducted to compare a PENG with a SFIB for controlling postoperative pain and for providing functional recovery.

Design: Noninferiority monocentric randomised controlled study.

Setting: One hundred and two patients scheduled for a total hip arthroplasty via the posterolateral approach under spinal anaesthesia were prospectively allocated to two groups. Data acquisition occurred between October 2021 and July 2022 at the University Hospital of Liege.

Patients: One hundred and two patients completed the trial.

Interventions: Group SFIB received supra-inguinal fascia iliaca block (SFIB) (40 ml ropivacaine 0.375%), whereas group PENG received a PENG block (20 ml ropivacaine 0.75%).

Main Outcome Measures: Rest and mobilisation pain on a 0 to 10 numeric rating scale at fixed time points: 1 and 6 h after surgery, on day-1 and day-2 at 8 a.m.,1 p.m. and 6 p.m. On day-1 and day-2, evolution of quality-of-recovery-15 score was assessed, and timed-up-and-go, 2 and 6 min-walking tests. The noninferiority margin was set as 1 numeric rating scale point 6 h after surgery.

Results: Six hours after surgery, pain scores in group PENG were noninferior to those of group SFIB, with a difference between medians at 0 (95% CI -0.93 to 0.93). There were no significant differences between the groups regarding rest and dynamic pain trajectories during the first 48 postoperative hours, with no significant effects of group (rest P  = 0.800; dynamic P  = 0.708) or interaction between group and time (rest P  = 0.803; dynamic P  = 0.187). Similarly, no significant differences were observed regarding motor and functional recovery as assessed by timed-up-and-go ( P  = 0.197), 2 min ( P  = 0.364), and 6 min walking ( P  = 0.347) tests and quality-of-recovery-15 ( P  = 0.417) score.

Conclusion: Following a total hip arthroplasty via the posterolateral approach, a PENG block is noninferior to SFIB regarding postoperative pain control 6 h after surgery, and functional recovery.

Trial Registration: European Clinical Trial Register under EudraCT-number 2020-005126-28 ( https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-005126-28/BE ).