Fascia Iliaca Block

  • Authors: Anna Forbes, Tapi Kundishora, James Waiting 
  • Editors: James Waiting
  • Reviewer: Thomas MacMahon, Mohammed Hamza
  • Codes: CAP23, CAP33, HAP19, PAP15, PAP17, PC1, PC3, PhC4, PhP1, SLO4, SLO5, SLO6, TC2, TP7
  • Published: 27/02/2023


The Fascia Iliaca (FI) Block was first described in the late 1980’s in the context of children undergoing lower limb surgery1. Its use for the management of femoral neck and shaft fractures in the emergency department has become more common since, initially using a landmark technique.

Ultrasound has been shown to increase the success of blocks and increases safety by allowing injection of local anaesthetic under direct vision2,3.

The use of FI blocks in the emergency department has been shown to provide effective pain relief in the acute setting and to reduce the use of opiate analgesia4,5. This is particularly important in the elderly population as it may decrease risk of delirium6.

It is important to remember that surgery is the definitive analgesia for hip fractures, and a patient’s journey to the operating theatre should not be unnecessarily delayed7.

Indications and Contraindications

The most common indication for fascia iliaca block in the emergency department is for a fractured neck of femur. It is now considered a part of the standard of care for this patient cohort.

NICE recommends that paracetamol should routinely be prescribed for these patients, along with judicious use of opiates8. Nerve blocks should be considered as an adjunct if preoperative pain relief is inadequate, or if opiates need to be limited for clinical reasons. Nerve blocks should never be considered a substitute for early surgery.

Nerve blocks should be administered by trained personnel. This could include nurse practitioners or paramedics in addition to physician practitioners9,10.

Absolute contraindications:

  • Competent patient refusal
  • Allergy to local anaesthetic
  • Infection over the proposed injection site

Relative contra-indications

  • Significant swelling around fracture site (risk of masking compartment syndrome)
  • Previous femoral bypass surgery (due to post-operative adhesions limiting anaesthetic spread within fascial plane)
  • Known peripheral neuropathy in the affected limb
  • Recent failed block (repeat blockade could be considered by an alternative operator provided cumulative safe anaesthetic dosage is not exceeded)

Anticoagulation (this is no longer an absolute contraindication, and with training and ultrasound guidance, nerve blocks can be considered for all anticoagulated patients)11.

The aim of the FI block is to introduce a high volume of local anaesthetic to spread into the potential space under the fascia iliaca. It targets the 3 nerves which run in this area. These are the femoral nerve, the lateral femoral cutaneous nerve and the obturator nerve. In the FI compartment block the obturator nerve is usually only partially blocked.

The needle is inserted laterally and the structures pierced during passage are skin, subcutaneous tissue, fascia lata and then fascia iliaca. The landmark technique has been called the “two pop” technique as loss of resistance is felt as the needle passes through the 2 fascial layers.

The ultrasound approach is safer and more accurate as it allows visual confirmation that local anaesthetic is delivered to the correct fascial plane.

The sonographic anatomy is shown in the later section on performing the block.

Preparing the equipment

A sample procedure pack would contain:

  • Sterile gloves
  • Chlorhexidine for skin cleaning
  • Sterile drape for skin
  • Sterile ultrasound cover
  • Sterile ultrasound jelly
  • Two 20ml syringes
  • Ultrasound nerve block needle (Size depends on size of patient 50mm to 100mm)
  • Blunt 19G Needle (for drawing up local anaesthetic)
  • Local anaesthetic (see later)
  • Dressing

An assistant may be required if a two‑person injection technique is required.

Preparing the equipment_image

Preparing the local anaesthetic

This is a volume dependent block. The effect is provided by spread of the local anaesthetic below the fascial layer, washing around the three targeted nerves. As a result, a low concentration and high volume of local anaesthetic is required.

Different trusts/hospital groups will have different protocols for FIB local anaesthetic regimes. Some will mix a rapid acting with a longer duration local anaesthetic, or may include steroid to prolong duration further (consult local guidelines in your hospital)12.

For simplicity and to reduce dose calculation errors, levobupivacaine alone is often used. It may have less cardio and neurotoxicity whilst providing similar analgesic effect as bupivacaine13.

Local anaesthetic maximum dose should probably be calculated using ideal body weight14.

The maximum safe dose of bupivacaine or levobupivacaine is 2mg/kg.

Worked example:

  • For 0.25% levobupivacaine, 1ml contains 2.5mg.
  • For a 50kg patient the maximum dose is 100mg. (2*50)
  • Therefore the maximum volume that can be given to this patient is 40mls

To allow a safe margin, no more than 30mls should be administered to a patient of this weight.

Preparing the patient

Ensure there are no contraindications to performing a FIB.

Gain informed consent by discussing the risks and benefits. Include the following risks:

  • Block failure (20%)
  • Nerve damage
  • Bleeding
  • Infection
  • LA toxicity, including the early signs of toxicity so the patient can report them immediately (see later)

Talk them through the procedure and allow them to ask questions. Consent should be documented in the patient’s notes.

Once this is done, position the patient flat on the bed (slight elevation of the head can be possible) with the leg slightly abducted and externally rotated (as pain allows).

Ensure there is a working IV cannula and the patient is connected to a cardiac monitor.

Method 1. Femoral artery identification and lateral scanning

Sonographic image_1 Sonographic image_2

Step 1. With probe marker pointing towards ASIS (from the femoral artery and vein are identified. The nerve lies lateral to the artery. Probe depth should be set to 3cm, and a linear 5-11Hz probe selected.

Sonographic image_3 Sonographic image_4

Step 2. The probe is moved lateral towards the ASIS, the iliacus muscle is identified with the fasia iliaca and fascia late superior.

Sonographic image_5

Sonographic image_6

Step 3. The needle is inserted and visualised in plane. A pop may be felt as it passes through the fascia lata and fascia iliaca. The needle should be placed under the fascia iliaca and the fascia hydro-dissected from the ilacus muscle. The syringe should be aspirated prior to infiltration, and then a test dose of 1-2mls injected to confirm position. The probe can scan medially to confirm spread towards the femoral nerve. (Local anaesthetic spread shown in blue.)

This flow chart can help guide you through the block process.

For further information on this block click here, An excellent video demonstrating the sonographic technique is available here.

Following the block, the patient should be observed for at least 30 minutes. Observations should be recorded at 5-minute intervals for the first 15 mins then at the 30-minute mark15.

The block should be recorded in the patient’s notes, documenting the site, side and time of the block, with the local anaesthetic prescribed on the patient’s drug chart.

The anaesthetic effect should last between 8 and 12 hours (if levobupivacaine used).

Local anaesthetic systemic toxicity (LAST) is rare with fascia iliaca block. Direct intravascular injection can be avoided by direct visualisation. It is important to be aware of the signs and symptoms. These include:

  • Oral numbness / paraesthesia
  • Disinhibition, restlessness, confusion
  • Muscle twitching, tremor
  • Hypertension, tachycardia
  • Reduced consciousness, hypotension, seizures, arrhythmias

The AAGBI has a clear summary which may be useful to print out and keep in the department.

Management includes stopping the infiltration, resuscitation, control of seizures and intravenous lipid emulsion (intralipid).

You should be aware of the location and availability of intralipid in your department.

  1. Dalens B, Vanneuville G, Tanguy A. Comparison of the fascia iliaca compartment block with the 3-in-1 block in children. Anesth Analg. 1989 Dec;69(6):705-13. Erratum in: Anesth Analg 1990 Apr;70(4):474.
  2. Scurrah A, Shiner CT, Stevens JA, Faux SG. Regional nerve blockade for early analgesic management of elderly patients with hip fracture – a narrative review. Anaesthesia. 2018 Jun;73(6):769-783.
  3. Lewis SR, Price A, Walker KJ, McGrattan K, Smith AF. Ultrasound guidance for upper and lower limb blocks. Cochrane Database Syst Rev. 2015 Sep 11;2015(9):CD006459.
  4. Fadhlillah F, Chan D, Pelosi P, Rubulotta F. Systematic review and meta-analysis of single injection fascia iliaca blocks in the peri-operative management of patients with hip fractures. Minerva Anestesiol. 2019 Nov;85(11):1211-1218.
  5. Amin NH, West JA, Farmer T, Basmajian HG. Nerve Blocks in the Geriatric Patient With Hip Fracture: A Review of the Current Literature and Relevant Neuroanatomy. Geriatr Orthop Surg Rehabil. 2017 Dec;8(4):268-275.
  6. Morrison RS, Magaziner J, Gilbert M, Koval KJ, et al. Relationship between pain and opioid analgesics on the development of delirium following hip fracture. J Gerontol A Biol Sci Med Sci. 2003 Jan;58(1):76-81.
  7. Membership of the Working Party; Griffiths R, Alper J, Beckingsale A, et al. Management of proximal femoral fractures 2011: Association of Anaesthetists of Great Britain and Ireland. Anaesthesia. 2012 Jan;67(1):85-98.
  8. National Institute for Health and Clinical Excellence. Hip fracture: management. NICE Clinical guideline [CG124], 2011. Last updated: 06 January 2023.
  9. Bulger JK, Brown A, Evans BA, Fegan G, Ford S, Guy K, et al. Rapid analgesia for prehospital hip disruption (RAPID): protocol for feasibility study of randomised controlled trial. Pilot and feasibility studies. 2017;3:8.
  10. Association of Anaesthetists of Great Britain and Ireland, Regional Anaesthesia UK. Fascia iliaca blocks and non-physician practitioners. AAGBI position statement 2013 London.
  11. Association of Anaesthetists of Great Britain and Ireland, Obstetric Anaesthetists’ Association, Regional Anaesthesia UK. Regional anaesthesia and patients with abnormalities of coagulation. Anaesthesia. 2013;68(9):966-72.
  12. Kumar N S, N K, M R, Sebastian D, Gowda Rm P. Dexamethasone as an additive to bupivacaine in fascia lliaca compartment block: a prospective, randomized and double blind study. J Clin Diagn Res. 2014 Aug;8(8):GC05-8.
  13. Gristwood RW. Cardiac and CNS toxicity of levobupivacaine: strengths of evidence for advantage over bupivacaine. Drug safety. 2002;25(3):153-63.
  14. Christie LE, Picard J, Weinberg GL. Local anaesthetic systemic toxicity. BJA Education. 2015;15(3):136-42.
  15. Royal College of Emergency Medicine (RCEM). Fascia Iliaca Block (FIB) Safety Newsflash, 2018.