Obturator Nerve Block in Patients With Hip Fracture (OPAD)

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.