The *Continuous peripherAl neRve blockadE FoR lowEr limb surgEry* (CAREFREE) trial

Patients undergoing (orthopedic) surgery are at risk for postoperative acute
and chronic pain. Reliance on opioids for pain management has led to growing
public health problems due to potential addiction. Additionally, opioids may
contribute to chronic postsurgical pain (CPSP). Peripheral nerve blocks (PNBs)
are state-of-the-art for postoperative analgesia in extremity surgery. PNBs
reduce opioid consumption, shorten hospital length of stay, improve pain
control and patient satisfaction, and prevent hospital readmission. However,
analgesic properties of single shot peripheral nerve blocks (sPNBs) last no
longer than 12 to 24 hours and may induce rebound pain, thereby leading
physicians to prescribe opioids.

Placement of a perineural catheter (continuous peripheral nerve block, cPNB)
assures continuous infusion of local anesthetic, ensuring ongoing analgesia and
reducing rebound pain. cPNBs are a regular part of in-hospital analgesic
treatment plans, however, outpatient cPNB is not yet common practice due to
organizational challenges resulting from financial restraints. Therefore,
current standard of practice utilizes multimodal analgesia consisting of sPNB
and opioids to expedite recovery and discharge. cPNBs can, however, play a role
in perioperative care for lower extremity surgery by facilitating quality of
analgesia comparable to in-hospital in an outpatient setting. Furthermore,
widespread adoption of cPNB may provide broad public health benefits by
limiting opioid requirement.

We hypothesize that implementation of ambulatory cPNB for postoperative
analgesia in lower limb surgery will be non-inferior regarding patient-reported
overall benefit of analgesia, when compared to standard care for pain control
using sPNB and systemic opioids. Ambulatory cPNB will be cost-effective, reduce
opioid consumption and incidence of CPSP, enhance patient-reported quality of
recovery, improve postoperative pain scores and shorten length of hospital
stay.

The main goal of this study is to investigate the effect of postoperative
analgesia using a cPNB on patient-reported overall benefit of analgesia, as
measured by the Overall Benefit of Analgesic Score (OBAS). It is hypothesized
that cPNB is non-inferior when compared to standard therapy for
patient-reported overall benefit of analgesia. Secondary objectives are to
study the effect on cost-effectiveness, postoperative opioid consumption,
length of hospital stay, postoperative pain, quality of recovery, and incidence
of CPSP.

Randomized clinical non-inferiority trial.

The proposed intervention in this study constitutes an organizational change.
Research subjects randomized to *fast-track recovery* participate in a novel
perioperative treatment pathway. In the intervention group, research subjects
receive a cPNB and are discharged as soon as medically reasonable. The control
group is treated for postoperative analgesia according to standard care, using
a sPNB and systemic opioids.

PNBs are a recognized expertise of anesthesiologists and as such cPNB is a
common part of in-hospital analgesic treatment plans. However, utilization of
outpatient cPNBs is currently limited due to organizational challenges
resulting from financial restraints. As such current standard of practice
utilizes multimodal analgesia consisting of sPNB and opioids to facilitate
recovery and discharge. This study will therefore explore cost-effectiveness as
a secondary objective.

cPNBs and sPNBs will be performed employing ultrasound guidance, by a selected
group of experienced anesthesiologists. Possible burden to research subjects
may be hospital readmission due to insufficient analgesia, this applies to both
the intervention arm and the control group. Research subjects will be requested
to complete questionnaires three days, thirty days and three months after
surgery. Benefits include the positive effects that cPNB may have on length of
hospital stay, postoperative pain, quality of recovery, and prevention of
negative side-effects of opioids.