Distal Nerve Blocks for Closed Reduction of Distal Forearm Fractures

Multicenter randomized controlled trial comparing the standard hematoma block as the local anaesthetic procedure for reduction of distal forearm fracture with ultrasound guided radial and median nerve blocks.

Among all dislocated fractures of the distal forearm only the true Colles' fracture can potentially be treated adequately with a closed reduction and a cast, while the other fracture types are unstable by definition and require surgical stabilization. Most dislocated forearm fractures, however, require a primary reduction and this procedure requires the patient to be relieved of pain and the muscle traction on the fracture to be minimal. The conventional local anaesthetic procedure used in Denmark is the hematoma block where the local anaesthetic agent is injected directly in the fracture. This is done using either a blind technique or with the aid of X-ray to visualize the fracture line. The radial and median nerves supply periosteal innervation for the radius and the ulna as well as muscular innervation for the majority of muscles in the forearm and wrist. Blocking these nerves at the level of the cubital fossa should relieve pain and minimize muscular traction when performing closed reductions on distal forearm fractures.

The investigators hypothesize that ultrasound guided blocking of the radial and median nerves will improve fracture reduction satisfaction for the true Colles' fractures and improve analgesia for reduction of all fracture types compared to the standard haematoma block.

Patients eligible for screening for inclusion are identified in the Emergency Department (ED) at all recruitment sites upon primary contact. When an X-ray has revealed the relevant fracture, the ED-staff will call the available anaesthesiologist or anaesthesiologist trainee who will perform the inclusion process and randomisation. Participants will be randomized in either the intervention or the control group using the online randomization tool Research Electronic Data Capture (REDCap, Aarhus University, Denmark). In both groups, the reduction process will begin 10 minutes after the block has been performed. The technique for the actual reduction may vary amongst physicians. To best reflect the clinical practices and to avoid the risk of an insufficient reduction due to the physician being forced to comply to a technique unfamiliar to him, no further standardisation will be made in this regard. Following casting of the fracture a control X-ray will be performed and subsequently evaluated independently by two skilled orthopaedic surgeons to establish if the reduction was satisfactory. In case of disputes a third orthopaedic surgeon will evaluate the X-ray and make a final ruling. The fracture will be deemed satisfactory using a binary outcome measure (yes/no) if all the following requirements set by the National Clinical Guideline for Treatment of Distal Radius Fractures are met.

Binary data, including primary endpoint will be analysed using chi squared test. For normally distributed measurements the differences between groups will be compared using Student´s t-test. Variables considered not to be normally distributed will be analysed by Mann-Whitney´s U-test. Two-tailed P-values < 0.05 will be considered statistically significant.