Effects of adductor-canal-blockade on pain and ambulation after total knee arthroplasty: a randomized study.
BACKGROUND
Total knee arthroplasty (TKA) is associated with intense post-operative pain. Besides providing optimal analgesia, reduction in side effects and enhanced mobilization are important in this elderly population. The adductor-canal-blockade is theoretically an almost pure sensory blockade. We hypothesized that the adductor-canal-blockade may reduce morphine consumption (primary endpoint), improve pain relief, enhance early ambulation ability, and reduce side effects (secondary endpoints) after TKA compared with placebo.


METHODS
Patients aged 50-85 years scheduled for TKA were included in this parallel double-blind, placebo-controlled randomized trial. The patients were allocated to receive a continuous adductor-canal-blockade with intermittent boluses via a catheter with either ropivacaine 0.75% (n = 34) or placebo (n = 37) (http://www.clinicaltrials.gov Identifier: NCT01104883).


RESULTS
Seventy-five patients were randomized in a 1 : 1 ratio and 71 patients were analyzed. Morphine consumption from 0 to 24 h was significantly reduced in the ropivacaine group compared with the placebo group (40 ± 21 vs. 56 ± 26 mg, P = 0.006). Pain was significantly reduced in the ropivacaine group during 45 degrees flexion of the knee (P = 0.01), but not at rest (P = 0.06). Patients in the ropivacaine group performed the ambulation test, the Timed-Up-and-Go (TUG) test, at 24 h significantly faster than patients in the placebo group (36 ± 17 vs. 50 ± 29 s, P = 0.03).


CONCLUSIONS
The adductor-canal-blockade significantly reduced morphine consumption and pain during 45 degrees flexion of the knee compared with placebo. In addition, the adductor-canal-blockade significantly enhanced ambulation ability assessed by the TUG test.
Department of Anaesthesia, Hamlet Hospital, Frederiksberg, Denmark.
M T
MT
Jenstrup
P
P
Jæger
J
J
Lund
J S
JS
Fomsgaard
S
S
Bache
O
O
Mathiesen
T K
TK
Larsen
J B
JB
Dahl
D000368:Aged; D000369:Aged, 80 and over; D000577:Amides; D016058:Analgesia, Patient-Controlled; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D000779:Anesthetics, Local; D019645:Arthroplasty, Replacement, Knee; D004311:Double-Blind Method; D023381:Endpoint Determination; D005260:Female; D006801:Humans; D007866:Leg / Q000294:innervation; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D009407:Nerve Block; D010147:Pain Measurement / Q000187:drug effects; D010149:Postoperative Pain / Q000188:drug therapy / Q000453:epidemiology*; D017060:Patient Satisfaction; D011229:Preanesthetic Medication; D011446:Prospective Studies; D000077212:Ropivacaine; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*
D000577:Amides; D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D009020:Morphine; D000077212:Ropivacaine