Programmed intermittent adductor hiatus block enhances early recovery after total knee arthroplasty: a randomized controlled trial.

backgroundMultimodal analgesia based on ultrasound-guided regional block is widely used after total knee arthroplasty (TKA). The goal of this study was to investigate the analgesic efficiency and knee motor function of programmed intermittent infusion combined with adductor hiatus block in total knee arthroplasty.

methodsThis prospective randomized controlled trial was approved by the Medical Ethics Committee of the First Affiliated Hospital of Chongqing Medical University (ethical approval number: 2024-302-01) and was registered in the Chinese Clinical Trial Registry ( http://www.chictr.org.cn , ChiCTR2400090031); the study was conducted from October 2024 to March 2025. A total of 148 patients undergoing unilateral total knee arthroplasty with general anesthesia were assigned to the continuous adductor canal block (CACB) group (G1, n = 50), the continuous adductor hiatus block (CAHB) group (G2, n = 50), or the programmed intermittent adductor hiatus block (PIAHB) group (G3, n = 48). The main outcome was the active flexion angle of the knee joint. The secondary outcomes were performance on the timed up-and-go (TUG) test; the muscle strength of the quadriceps femoris, ankle dorsiflexors, and metatarsal flexor; and Visual Analogue Scale (VAS) scores of anterior and posterior sides of the knee at rest and during active 30-degree flexion.

resultsThe PIAHB group had a significantly greater active knee flexion angle than the CAHB and CACB groups on the 1st, 2nd, and 3rd post-operative days (F = 14.313, p < 0.001; F = 16.793, p < 0.001; and F = 18.097, p < 0.001, respectively); the TUG times in the PIAHB group were shorter than those in the CAHB and CACB groups on the 1st and 2nd post-operative days (F = 26.059, p < 0.001) (F = 18.102, p < 0.001), but there was no difference in TUG test results on the 3rd post-operative day. There was no significant difference in the muscle strength of lower limb; VAS scores of the posterior side of the knee at rest and during active flexion were significantly lower in the PIAHB group than in the CAHB and CACB groups (F = 5.860, p = 0.004; F = 80.015, p < 0.001), but there was no difference in the VAS scores of the anterior side of the knee. The number of patients receiving remedial analgesia within 72 h was reduced in the PIAHB group (F = 7.405, p = 0.030), and the consumption of ropivacaine was significantly reduced in that group (F = 24.995, p < 0.001), but there was no difference in the incidence of postoperative complications or in HSS (post-operativeHospital for Special Surgery) scores 6 months post-operatively.

conclusionsPIAHB increased the analgesic effect on the popliteal fossa without decreasing the strength of the quadriceps femoris, resulting in improved ROM on the 1st and 2nd post-operative days in patients who underwent TKA.