Obturator Nerve Block in Patients With Hip Fracture

Proximal Obturator Nerve Block After Insufficient Analgesic Effect of Femoral Nerve Block in Patients With Hip Fracture

About 10-30% of all patients with hip fracture have only insufficient analgesic effect of a femoral nerve block. One of the possible causes of this failure to provide analgesia from a single nerve block could be the that other nerves occasionally are involved in transmitting the pain signal. One of the nerves that is believed to give off branches to the hip is the obturator nerve.

With ultrasound it is possible to make a selective proximal nerve block of the obturator nerve.

The aim of this trail is to give patients with hip fracture and only insufficient effect of a femoral nerve block a supplementary obturator nerve block in a randomized manner with either local anesthetics or placebo in order to access the preoperative analgesic effect.

About 10-30% of all patients with hip fracture have only insufficient analgesic effect of a femoral nerve block. One of the possible causes of this failure to provide analgesia from a single nerve block could be the that other nerves occasionally are involved in transmitting the pain signal. One of the nerves that is believed to give off branches to the hip is the obturator nerve. Earlier it was believed that the so called '3-in-1-block' or the iliac fascia compartment block would anesthetize also the obturator nerve, and these two nerve blocks have been uses extensively in the emergency ward for preoperative analgesia. Today that is not believed to be true and consequently is the part of the obturator nerve in patients with hip fracture unknown.

With ultrasound it is possible to make a selective proximal nerve block of the obturator nerve before it branches into an anterior and a posterior branch. A selective nerve block af the obturator nerve to access its effect in patients with hip fracture has to our knowledge never been done.

The aim of this trail is to give patients with hip fracture and only insufficient effect of a femoral nerve block a supplementary obturator nerve block in a randomized manner with either local anesthetics or placebo in order to access the preoperative analgesic effect.

Inclusion Criteria:

• Clinical suspicion of hip fracture
• Successful sensory cutaneous effect of the femoral nerve block
• Age ≥ 55 years
• Mentally capable of comprehending and using verbal pain score
• Mentally capable of differentiating between pain from the fractured hip and pain from other locations
• Mentally capable of understanding the given information
• Arrival in the emergency room at times when one of the doctors who do the nerve blocks for this investigation are on call
• Possible sonographic visualization of the structures needed for the nerve block
• Verbal numeric pain scale score (NRS 0-10) > 5 with passive leg raise of the fractured leg at the time of inclusion OR NRS > 3 at rest, 30 minutes after a femoral nerve block
• Patients informed consent

Exclusion Criteria:

• Hip fracture not confirmed by x-ray
• Weight < 45 kg
• Patient has previously been included in this trial
• If the patient wishes to be excluded
• Allergy to local anesthetics or adrenocortical hormone
• Visible infection in the area of the point of needle injection