Single-injection nerve blocks for total knee arthroplasty: femoral nerve block versus femoral triangle block versus adductor canal block—a randomized controlled double-blinded trial

Abstract

Introduction Femoral nerve block (FNB) is a well-established analgesic technique for TKA. However, it associates quadriceps weakness. Therefore, femoral triangle block (FTB) and adductor canal block (ACB) were proposed as effective alternative motor-spearing techniques. The primary objective was to compare quadriceps muscle strength preservation between FNB, FTB and ACB in TKA. The secondary objective was to analyze pain control and functional outcomes. Methods This is a prospective, double-blinded RCT. From April 2018 to April 2019, patients who undergo a primary TKA were randomized into three experimental groups: FNB-G1/FTB-G2/ACB-G3. Quadriceps strength preservation was measured as the difference in maximum voluntary isometric contraction (MVIC) preoperatively and postoperatively. Results Seventy-eight patients (G1, n = 22; G2, n = 26; G3, n = 30) met our inclusion/exclusion criteria. Patients with FNB retained significantly lower baseline MVIC at 6 h postoperatively (p = 0.001), but there were no differences at 24 and 48 h. There were no differences between the groups in functional outcomes at any time point. Patients in the FNB-G1 presented significant lower pain scores at 6 h (p = 0.01), 24 h (p = 0.005) and 48 h (p = 0.01). The highest cumulative opioid requirement was reported in ACB-G3. Conclusion For patients undergoing TKA, FTB and ACB preserve quadriceps strength better than FNB at 6 h postoperatively, but there are no differences at 24 and 48 h. Moreover, this early inferiority does not translate to worse functional outcomes at any time point. FNB is associated with better pain control at 6, 24 and 48 h after surgery, while ACB presents the highest cumulative opioid requirement. Clinical trial registration This study was registered in clinicaltrials.gov (NCT03518450; https://clinicaltrials.gov/ct2/show/NCT03518450; submitted March 17, 2018).

The Effects of Perineural Dexamethasone on Rebound Pain After Nerve Block in Patients with Unicompartmental Knee Arthroplasty A Randomized Controlled Trial

“…In recent years, single adductor canal block and continuous catheter adductor canal block have been widely studied in nerve block analgesia for knee surgery. However, considering the limited analgesic effect of adductor canal block, it is necessary to routinely use high-dose opioids to aid analgesia during surgery 12 . The use of opioids, especially remifentanil, is likely to cause postoperative hyperalgesia, which is one of the risk factors for the occurrence of rebound pain, and it will interfere with the treatment outcomes 13,14 .…”