Comparison of Continuous Proximal Versus Distal Adductor Canal Blocks for Total Knee Arthroplasty

Abstract

ClinicalTrials.gov (NCT02701114).

Continuous Block at the Proximal End of the Adductor Canal Provides Better Analgesia Compared to that at the Middle of the Canal After Total Knee Arthroplasty: A Randomized, Double-blind, Controlled Trial

“…RCTs by Mariano 5 , Romano 6 and Meier 7 had investigated the "proximal AC" and "distal AC" and failed to detect signi cant differences in regard to 24 h postoperative opioid consumption, as well as in quadriceps strength or motor function. The discrepancies between the present study and these three RCTs can likely be attributed to the different de nitions of the AC [5][6][7] . Base on their description, these studies actually compared the distal FT 5,6 or the proximal AC 7 with a more cephalad injection in the FT 5-7 , instead of the distal AC with the proximal AC.…”

“…First, the quadriceps muscle strength was only evaluated manually by a physiotherapist on a Lovett's scale, which is not as precise as by using the force dynamometer such as the measurement of maximum voluntary isometric contraction. 7,29 In addition, we did not implement a validated test to measure patient mobilization ability, such as the Timed "Up and Go" measurement, 30 which could directly re ect the balance between "pain-control during movement" and "preserving strength" that is important for effective pain management after TKA. 31 The current study is unable to show whether continuous infusion will increase blockade related side effects.…”

“…4 The optimal location for continuous ACB for TKA has been investigated by previous randomized clinical trials (RCTs). [5][6][7][8] However, identi cation of the adductor canal (AC) was not consistent, [5][6][7][8] and the results differed. The AC is a musculoaponeurotic tunnel that runs proximally from the apex of the femoral triangle (FT)/proximal end (entrance opening) of the AC where the medial borders of the sartorius muscle (SM) and adductor longors muscle (ALM) align, to the adductor hiatus distally where the femoral artery (FA) diverges from the SM and becomes deep.…”

Is the proximal adductor canal block a better choice than the distal adductor canal block for primary total knee arthroplasty?

“…Among the 5 RCTs, 3 RCTs [ 16 , 19 , 20 ] reported using computer-generated randomization. Two RCTs [ 17 , 18 ] described allocation concealment via sealed envelopes or other methods. A double-blind method was carried out in 2 studies.…”

‘Inverse Double Bubble’ sign for an effective adductor canal block: a novel approach for the ultrasound confirmation of being on the right site

“…In daily clinical practice, US-ACB is usually performed by a distal approach or alternatively by a proximal one, at the midpoint of the thigh. A successful block needs the identification of the superficial femoral artery deep to the sartorius muscle and the needle to pass over the subsartorial membrane (SSM) to enter the adductor canal, where a volume of 20 mL of local anesthetic is injected 6. However, in some cases it could not be easy to understand if the SSM has been crossed by the needle, especially in obese or old patients, who may have deeper or not easily detectable target anatomic structures.…”