Comparison of Adductor Canal Block and Femoral Triangle Block for Total Knee Arthroplasty.

Objectives: Adductor canal block (ACB) could provide effective postoperative pain control for patients after total knee arthroplasty (TKA). However, some authors pointed out that the ACB as originally described may be more similar to a femoral triangle block (FTB). Recent neuroanatomic evidences made the authors conjecture that the "true" ACB would provide superior analgesia compared with FTB. Therefore, the study was designed to determine the hypothesis that postoperative analgesia after TKA could be improved by a "true" ACB compared with FTB.

Materials And Methods: Patients undergoing unilateral, primary TKA were randomized into the ACB group or FTB group. The primary outcome was postoperative pain during active flexion at 8 hours after surgery measured by the visual analog scale (VAS). In addition, pain scores at other time points, quadriceps strength, morphine consumption, satisfaction of the patient, and side effects of morphine were also evaluated.

Results: Sixty participants completed the research. The VAS scores were lower in the ACB group than the FTB group at 8 and 24 hours at rest (P<0.05). The VAS scores were lower in the ACB group than the FTB group at 4, 8, 24, and 48 hours during active flexion (P<0.05). The quadriceps strength was superior in the ACB group than the FTB group at 4, 8, and 24 hours (P<0.05). The consumption of morphine was lower in the ACB group than the FTB group (P<0.05). However, there were no significant differences for both patient satisfaction and the incidence of adverse reactions (P>0.05).

Discussion: ACB can provide superior analgesia and preserve more quadriceps strength than FTB. ACB facilitates functional recovery in the early stages and is compatible with the highly recognized concept of rapid rehabilitation, which should be promoted in the clinic.