Comparison of suprainguinal fascia iliaca compartment block and adductor canal block for postoperative analgesia in total knee arthroplasty: a randomized clinical trial

This study aimed to compare suprainguinal fascia iliaca compartment block (S-FICB) and adductor canal block (ACB) in terms of postoperative pain scores, opioid consumption, and clinical outcomes in total knee arthroplasty (TKA). In this prospective, randomized clinical trial conducted in Turkey, patients undergoing TKA under spinal anesthesia were randomized to receive either S-FICB or ACB. Postoperative pain at rest and with movement was evaluated using a numerical rating scale (NRS). Opioid consumption, duration of motor block, patient satisfaction, and adverse effects, such as nausea, vomiting, and pruritus, were also recorded. Eighty-six patients were analyzed (S-FICB: n = 43; ACB: n = 43). Longitudinal analysis using generalized estimating equations demonstrated significant overall treatment-group effects for resting and movement NRS scores over the first 24 postoperative hours (Wald χ 2 = 7.29, p = 0.007 and Wald χ 2 = 17.09, p < 0.001, respectively). In exploratory Mann–Whitney U comparisons performed to facilitate clinical interpretation, median (IQR) resting NRS scores in the S-FICB and ACB groups were 1 (0–2) versus 1 (0–3) at 1 h, 2 (1–3) versus 3 (2–4) at 12 h, and 2 (1–3) versus 3 (2–4) at 18 h, respectively (all p < 0.05). Movement NRS scores were significantly lower in the S-FICB group at all assessed time points (all p < 0.05). Total 24-h opioid consumption was significantly lower in the S-FICB group ( p = 0.002). Although motor block duration was longer, patient satisfaction scores were higher with S-FICB than with ACB ( p < 0.001 and p = 0.006, respectively). Under the dosing protocols evaluated in this study, S-FICB was associated with lower postoperative pain scores, reduced opioid consumption, and higher patient satisfaction compared with ACB following TKA. These findings, however, should be interpreted with caution because different local anesthetic doses and injectate volumes were used in the two treatment groups. The study was registered at ClinicalTrials.gov (NCT07040709) on June 10, 2025; retrospectively registered.