"Supracondylar Radial Nerve Block Guided by Ultrasound Versus Hematoma Block for Analgesic Management in Closed Reduction of Distal Radius Fractures"

Approval has been obtained from the ethics committee. A process of informed consent will be conducted with all participants, ensuring confidentiality and data protection. Once the informed consent is signed, either an orthopedic surgeon or resident will gather demographic data such as age, sex, height, weight and analgesics taken during the same day of the intervention. Additionally, the type of fracture according to the AO classification and the perceived pain before the intervention will be registered in REDCap

Subsequently, this healthcare personnel in the emergency room will contact a member of the research team, who will conduct randomization of the intervention though REDcap and determine which analgesic approach should be offered to the participant.

Training and education will be provided to orthopedic surgeons working in the emergency room to standardize the local analgesic interventions, following the recommendations outlined in the study protocol.

Since this study involves two non-invasive, clearly distinguishable interventions, it is not possible to blind the patient to the assigned treatment or to blind the healthcare professionals administering the intervention or recording the outcome. However, data analysis will be conducted with blinding of the administered intervention.

After a 10-minute waiting period following the analgesic procedure, the participants' pain will be reassessed using the numeric pain scale. After this, all patients will undergo closed reduction through manual reduction maneuvers. This involves the patient being placed in supine position, while two doctors perform traction along the axis of the arm and countertraction at the elbow for 2-5 minutes to impact the fracture. Subsequently, wrist extension, flexion, and ulnar deviation of at least 15° will be performed, with manual pressure applied on the dorsal aspect of the radius if necessary. Finally, the patient will be immobilized with a brachy metacarpal closed cast or splint, and post-reduction radiographs will be taken. Patients will be asked to rate the pain experienced during this reduction.

Radiographs before and after the reduction will also be taken, following a standardized protocol. The posteroanterior projection will be performed with the wrist and elbow at shoulder height, aligning the joints in the transverse plane. The palm of the hand will be in contact with the cassette, as in this position, the radius and ulna are parallel. The lateral projection will be taken with the shoulder, elbow, and wrist aligned in the sagittal plane, positioning the edge of the distal ulna on the cassette. In the posteroanterior projection, the radial height, ulnar variance, and radial inclination will be measured, while the dorsal/volar tilt will be measured on the lateral projection.

Finally, all complications during the procedure or adverse effects occurring 3 hours after the intervention will be registered.

An intention-to-treat analysis will be conducted. Descriptive statistics will be generated using R studio for the demographic variables. The proportion of patients experiencing a reduction greater than two points (which corresponds to the minimal clinically important difference) between baseline pain and pain experienced after the analgesic procedure and during the reduction will be registered and compared using an exact Fischer test.

Additionally, the proportion of patients with an adequate reduction will be compared between the two interventions for each of the radiographic measures, categorized as within or outside the ideal range. Finally, the proportion of complications and adverse effects for each intervention will be compared using an exact Fischer test.

An interim analysis will be conducted when half of the sample has been recruited to evaluate the efficacy and safety of the interventions in a blinded manner. The study will conclude if clear benefits are found with an intervention or if statistically significant harm is evidenced. An O'Brien-Fleming method will be employed to adjust the significance level for this interim analysis, aiming to control Type I error.

The results will be reported collectively for publication in a peer-reviewed journal.

Inclusion criteria

• Patients over 18 years old with skeletal maturity evidenced in the initial radiographs.
• Patients with a radiological diagnosis of distal radius fracture
• Patients whose clinical condition is considered acute (duration of symptoms less than one week).
• Patients who have an indication for closed reduction as a definitive or initial management of their distal radius fracture
• Patients treated at San Ignacio University Hospital in Bogotá, Colombia

Exclusion criteria

• • Patients with bilateral distal radius fractures

• Patients with open distal radius fractures.
• Patients with another fracture in the same limb
• Patients in a state of intoxication or under the influence of psychoactive substances.
• Patients with hemodynamic instability that prevents prioritizing closed reduction as management.
• Patients with a known allergy to local anesthetics
• Patients on full-dose anticoagulant therapy.
• Patients who refuse to participate in the study
• Patients with cognitive, visual, or auditory impairments that prevent the proper completion of questionnaires