Analgesic efficacy of the continuous femoral nerve block in combination with the posterior infiltration of the posterior knee capsule for total knee replacement surgery

Abstract

Postoperative acute pain is a sub treated entity as it was demonstrated by Apfelbaum in 2003 when he
published one of the most important articles in the subject. Several therapeutic options have been described
for total knee replacement (TKR) postoperative pain. Some authors state that the best analgesic option for
this surgery is the one that not only offers no pain in a secure fashion but also adequate to the capabilities
and the environment of the treating anaesthesiologist. In the quest of an optimal analgesic treatment for
TKR scheme two analgesic technics were compared in a single medical institution. In order to identify the
best option an observational, retrospective and analytic study was conducted in patients that were scheduled
for TKR in Clinica Universitaria Reina Fabiola; patients were randomized in two groups: EV Group
(received an intravenous analgesic scheme) and BNPC + LIA Group (received a combined analgesic
scheme that consisted in a continuous femoral nerve block combined with a posterior knee capsule
intraoperative infiltration with a local anaesthetic mixture). The result analysis demonstrated a reduced
global opioid consumption in the BNPC + LIA Group (Group BNPC + LIA: 6,16 ± 4,68 mg Vs Group EV:
11,33 ± 8,89 mg; p= 0,01) (figure 1 - Table 1). Moreover, a prolongation in the hospital stay in the BNPC
+ LIA Group was detected (BNPC + LIA 3,20 ± 0,92 Vs Group EV 2,62 ± 0,96; p=0,008) (figure 2). Finally
a statistic difference was also detected in the occurrence of postoperative complications (figure 3) that
favoured the BNPC + LIA Group (Group BNPC + LIA: 0,26 ± 0,44 Vs Group EV: 0,66 ± 0,78; p=0,04).
In the light of this results, we can affirm that the combination of a continuous femoral nerve block and
intraoperative infiltration of the posterior knee capsule with local anaesthetics is a secure and effective
analgesic option for postoperative TKR acute pain. mitosis/mm.
.