Distal extremity fractures are commonly seen in the Emergency Department. These fractures often require closed reduction by manipulation which can be a painful and frightening experience for the patient. Achieving adequate analgesia is important to facilitate reduction and to minimize patient discomfort. Physicians frequently provide inadequate analgesia to patients, and particularly children, with extremity fractures.1,2
ANATOMY AND PATHOPHYSIOLOGY
The hematoma block is a technique to inject a local anesthetic solution into the hematoma between the fractured bone fragments. Fracture manipulation can often be undertaken painlessly or with significantly reduced pain after performing a hematoma block. Hematoma blocks of the distal forearm are considered safe in children and adults.3-8 A hematoma block may be superior to intravenous sedation in alleviating discomfort during fracture reduction.9 Other advantages are the relative ease of the procedure, no worries concerning aspiration, and ability to potentially manage the airway. The hematoma block avoids the side effects of sedating drugs, does not require intravenous access and cardiac monitoring, and is not associated with a prolonged recovery phase. The Emergency Physician can safely perform a hematoma block alone whereas two health care providers are needed for procedural sedation. The disadvantages of the hematoma block include the discomfort and anxiety resulting from injecting into the fracture site. There is the potential for a rare complication.
Extremity fractures that are displaced or angulated result in the formation of a hematoma between the fracture fragments. The hematoma is easily accessible with a needle. The injection of local anesthetic solution can significantly alleviate pain. Most important neurovascular structures in the upper extremity are contained in the volar soft tissue, making the dorsal or lateral approach preferred. Most important neurovascular structures in the lower extremity are contained in the proximal anterior thigh or posteriorly in the leg, making the lateral approach preferred in the proximal thigh and the anterior or lateral approach from the mid-thigh distally.
Other techniques are available to provide analgesia and anesthesia. A Bier block (Chapter 157) may lead to more effective anesthesia and require fewer repeat manipulations for the reduction of forearm fractures when compared to the hematoma block.10-12 The Bier block is a technique with which most Emergency Physicians are not familiar and have not developed proficiency. It often requires equipment not commonly available in the Emergency Department and can be associated with adverse outcomes. Intraarticular injection of local anesthetic solution for the reduction of intraarticular fracture-dislocations has been advocated as safe and effective.13,14 The joints of the extremities are easily entered by performing an arthrocentesis (Chapter 97). Local anesthetic solution injected intraarticularly diffuses throughout the joint cavity and exits through the fracture site to alleviate pain.
A hematoma block is indicated in adult and pediatric patients with closed fractures of the extremity that require manipulation ...