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. However, studies suggest that Physicians frequently provide inadequate analgesia to patients, and particularly children, with extremity fractures.1,2
The hematoma block is a technique to inject a local anesthetic solution into the hematoma between the fractured bone fragments. Fracture manipulation can then often be undertaken painlessly or with significantly reduced pain. Hematoma blocks of the distal forearm are considered safe in children and adults.3–8 Another advantage is the relative ease of the procedure. A hematoma block may be superior to intravenous sedation in alleviating discomfort during fracture reduction.9 The hematoma block, unlike procedural sedation, avoids the side effects of sedating drugs, does not require intravenous access and cardiac monitoring, and is not associated with a prolonged recovery phase. One Physician can safely perform a hematoma block, whereas the presence of two Physicians is generally recommended for procedural sedation. The disadvantages of the hematoma block include the discomfort and anxiety resulting from injecting into the fracture site, and the potential for a rare complication.
Extremity fractures, when displaced or angulated, generally result in the formation of a hematoma between the fracture fragments. The hematoma is easily accessible with a needle and the injection of local anesthetic solution can significantly alleviate pain. The majority of important neurovascular structures in the upper extremity are contained in the volar soft tissue, making the dorsal or lateral approach preferred. The majority of 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. Some authors have concluded that a Bier block (intravenous regional anesthesia, Chapter 127) may lead to more effective anesthesia and require fewer re-manipulations for the reduction of forearm fractures when compared to the hematoma block.10–12 However, the Bier block is a technique that most Emergency Physicians are not familiar and have not developed proficiency, 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, though not as well studied or widely utilized as a hematoma block, have also been advocated as safe and effective.13,14 The joints of the extremities are easily entered by performing an arthrocentesis (Chapter 77). 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 ...