3.2 Neuraxial Anesthesia Reduces Perioperative
Morbidity and Mortality
Neuraxial anaesthesia (epidural and spinal anaesthesia) is
an important component of the multimodal approach to
pain management both during and after total knee
replacement. Compared with general anaesthesia, neuraxial
and combined neuraxial-general anaesthesia was associated
with lower 30-day mortality, length of stay, and in-hospital
complication rate in a large population-based study of hip
and knee arthroplasty patients [20] and supported earlier
data also demonstrating reduction in morbidity and mortality
[21]. This reduction in perioperative morbidity and
mortality may be especially relevant for elderly patients
who frequently have pre-existing risk factors for perioperative
complications. For postoperative pain management,
continuous epidural analgesia has been shown to provide
pain relief similar to that of continuous FNB (cFNB);
however, it is associated with more frequent side effects
than cFNB [4]. Intrathecal morphine has also been demonstrated
to provide effective analgesia after TKA with
similar results [22] compared with single-injection FNB
(SFNB) [23]. Intrathecal morphine is associated with a
greater frequency of side effects including nausea, vomiting,
and pruritus, and decreased patient satisfaction [23]. A
meta-analysis of side effects related to intrathecal morphine
(non-specific to knee arthroplasty) suggested that
low-dose intrathecal morphine was associated with more
nausea, vomiting, and pruritus than placebo but only highdose
morphine was associated with more frequent respiratory
depression [24]. Overall, the addition of intrathecal
morphine to spinal anesthesia can provide effective pain
relief but, because of the significant risk of side effects,
would not be a technique of first choice, especially when
used in isolation [25].