Postop Pain Control in Hip Fracture Surgery: Fascia Iliaca Compartment Block Versus Fracture Block

The incidence of fragility hip fractures in elderly patients is increasing steadily in the United States and worldwide, and the mortality, morbidity and economic impact of this injury is staggering. The injury itself can result in severe pain, both preoperatively and throughout the perioperative course. These patients are also at increased risk for delirium. They are by definition elderly, and often have multiple comorbidities in addition to underlying cognitive dysfunction. Current studies estimate that the incidence of delirium after a hip fracture approaches 30%, and there is a well-established though not completely understood interaction between opioid use in elderly patients and delirium. Pain and delirium are not only poor outcomes in themselves, but they can also interfere with the rehabilitation necessary for a successful outcome after hip fracture surgery. For this reason, the topic of multimodal pain management in hip fracture patients has gained considerable traction.

One popular "opioid-sparing" strategy in these patients is regional pain blockades, administered by an anesthesia block team or by emergency room physicians. Due to the neuroanatomy of the hip region, which has sensory innervations from the sciatic, femoral, and obturator nerve, with lesser contributions from the nerve to quadratus femoris and superior gluteal nerve, effective regional blockade of the hip joint with existing methods can be a challenge. One commonly employed and researched block is the fascia iliaca compartment block (FICB), a regional block administered under ultrasound guidance or anatomical landmarks that targets the femoral nerve, the lateral femoral cutaneous nerve, and to a lesser extent, the obturator nerve. Various studies of FICB and the closely related femoral nerve block have demonstrated benefits in pain control, ease of positioning, and reduction in opiate use, and systematic reviews have concluded that the fascia iliaca compartment block is a useful and safe method to enhance preoperative pain control in hip fracture patients. However, prior research has focused on the preoperative period, with blocks placed by an anesthesia team or emergency room physicians shortly after presentation and diagnosis of a hip fracture. Additionally, no distinction is made between intracapsular or extracapsular hip fractures, except in scattered post-hoc analyses. Our project aims to investigate the efficacy of a FICB administered intraoperatively by the operating surgeon on extracapsular hip fracture patients. In addition, the investigators propose investigating intrafragmentary blockade at the fracture site itself. Fracture hematoma blocks are used extensively in orthopedics, and have demonstrated pain control equivalent to conscious sedation for the manipulation of ankle and distal radius fractures.

Study Design

The investigators propose to investigate the effect of intraoperative FICB and intrafragmentary fracture blockade on postoperative pain and opiate consumption using a randomized controlled trial study design. There will be three treatment groups: (1) fascia iliaca compartment blockade administered after surgical fixation using the loss of resistance technique with 30cc 0.25% marcaine (2) intrafragmentary fracture block using fluoroscopy guidance after surgical fixation with 30cc 0.25% marcaine and (3) placebo group, with no intervention

Randomization will occur at time of enrollment using unmarked envelopes. After consent, patients will be assigned a study ID that will be transcribed on the opaque envelope. The envelope will be unsealed in the operating room at time of surgery to determine the planned intervention, and it's contents will not be made available to the study personnel gathering postoperative pain data. The envelopes and randomization assignments will be kept in a locked, secured location. The only study personnel who will be unblinded are the operating surgeon and residents and physican assistants assisting in the operating room. Study personnel who participate in the case will not collect postoperative pain data.

The investigators will monitor various safety outcomes, including perioperative cardiac or respiratory events, mortality, and escalation of care (i.e. SICU transfer). Each adverse event will be analyzed by the senior operating surgeons to determine if the study intervention could have had a role in the event.

Our outcome measurements are pain visual analogue scores and narcotic use postoperatively. Calculations of narcotic use will be standardized to IV morphine equivalents. The associated primary and secondary hypotheses are as follows:

• Primary: There is a statistically significant difference in pain visual analogue scale (VAS) between extracapsular hip fracture patients treated intraoperatively with fascia iliaca block, fracture block, or conventional analgesia in the first 24 hours postoperatively.
• Secondary: There is a statistically significant difference in opioid consumption (measured in IV morphine equivalents / time) between extracapsular hip fracture patients treated intraoperatively with fascia iliaca block, fracture block, or conventional analgesia in the first 24 hours postoperatively.

Study Population

Our study population will be focused on elderly patients with low energy extracapsular (intertrochonteric, subtrochanteric) hip fractures. Inclusion criteria will include age 60 years or older, low energy mechanism (i.e. mechanical or syncopal fall from ground level), and extracapsular location as defined on AP and lateral radiographs of the hip. Exclusion criteria includes polytrauma patients with multiple injuries, high energy mechanisms (i.e. pedestrian struck, motor vehicle collision, fall from height), inability for the patient to consent for themselves, pathologic fracture types (secondary to tumor or atypical fractures due to bisphosphonate use), and intolerance or allergies to opioids or local anethestics.

Sample size projections target a sample of 105 patients, 35 in each group. This is based on calculation of 80% power to detect a 10mm difference in the VAS score using means and standard deviations from previous publications with measurements of pain scores in hip fracture patients. Since the duration of followup is limited to the immediate postoperative period, the investigators do not anticipate a significant drop out or loss-to-follow up rate.

Recruitment

Recruitment will occur in the emergency department by study personnel. After diagnosis of an extracapsular hip fracture is made, the exclusion and inclusion criteria will be reviewed, and eligible patients will be approached for voluntary participation in the research study.

Informed Consent

Study personnel will obtain consent in the emergency room or shortly after admission to the floor. Please find attached the planned consent form.

Risks

The proposed intervention, marcaine for regional blockade, has been studied extensively, and has been demonstrated to be safe. The risk of intravascular introduction of lidocaine is possible, but exceedingly rare. Per standarad procedure, the investigators will plan to aspirate the syringe before injection to confirm extravascular targeting. Another known risk of regional blockade is muscle weakness in the immediate postoperative period due to blockade of motor nerves. If not appropriately managed, this could create a risk of falling. Patients are routinely assessed by physical therapy for strength and muscle control before attempting ambulation postoperatively, and this will continue to be the practice. Furthermore, postoperative hip fracture patients, if they do ambulate post operative day 0, are closely assisted by physical therapists, reducing the risk of fall.

Data Analysis

Differences between study groups in regards to their baseline characteristics and outcomes will be assessed using two-sided Fisher's exact tests, chi-square tests for categorical variables, and independent samples student T-tests for continuous variables. The investigators will plan to undertake a multivariable analyses as well.

Data Quality and Management

The investigators plan to use a REDCap database for data collection and monitoring. Patient specific data will be entered by study personnel into the REDCap database after completion of the patient's intervention and postoperative followup. This will avoid disrupting the blinding of study personnel gathering postoperative pain data. Postoperative narcotic use will be gathered from a chart review of ordered and administered medications.