Wrist Fracture in Emergency Medicine

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Background

The wrist is the most commonly injured region of the upper extremity. Fractures of the distal radius and ulna account for three fourths of wrist injuries. The carpal bones themselves are injured much less frequently but account for up to 10% of injuries to the structures of the hand. Not only are these injuries frequently encountered in the emergency department setting, but the mobility and delicate functional requirements of the hand make accurate diagnosis and treatment crucial to avoiding long-term loss of function and disability.

Volar dislocation of the lunate is shown in the image below.


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Lateral radiograph of the wrist illustrating volar dislocation of the lunate.

Pathophysiology

Anatomic considerations

The wrist or carpus is a highly mobile structure composed of a large number of small bones and joints. This complex system of articulations works in unison to provide a global range of motion for the wrist joint. Motion at the wrist joint occurs between the radius and the carpal bones, which function as a single unit, and between the carpals and metacarpals.

Carpal fractures and dislocations

Fractures of the distal radius and ulna

Fractures of the distal radius, ulna, or both account for approximately three quarters of bony injuries of the wrist. The radius articulates directly with the carpal bones; the ulna has attachments to the triangular fibrocartilage, which is interposed between the distal ulna and the triquetrum in the proximal row of carpal bones. The radius and ulna themselves articulate at the DRUJ, about which occurs the movements of supination and pronation at the wrist. They are enveloped in a common joint capsule and share multiple ligamentous attachments. Along the midshaft of both bones is the interosseus membrane. Several muscle groups attach on the distal aspect of both bones and contribute to the displacement of fracture fragments.

Epidemiology

Frequency

United States

Fractures of the distal radius account for one sixth of all fractures seen and treated in the ED.

Mortality/Morbidity

Little or no risk of death is associated with isolated wrist fractures. The potential does exist for substantial morbidity, including primarily arthritis, chronic pain, limitation of motion, and physical deformity. Morbidity also may be related to associated injuries, including those of the median and ulnar nerves and the radial and ulnar arteries.

Age

Patients aged 6-10 years and those aged 60-69 years have the greatest frequency of distal radius fractures. Injuries to the carpal bones are common in all age groups but are more common in adolescents.

History

History for wrist fracture includes the following:

Physical

Physical examination should begin with inspection of the injured extremity using the uninjured extremity as a comparison. The site of injury may be identified by ecchymosis or swelling. Fractures of the distal radius may have characteristic deformities. Look for any evidence of a break in the skin indicating an open fracture. Palpation with localization of the point of maximal tenderness further defines the injury.

Causes

Causes of wrist fracture are as follows:

Scaphoid navicular

Other mechanisms of injury have recently come to light in addition to a fall on the outstretched hand with hyperextension. These include forced palmar flexion of the wrist with axial loading of the wrist in a fixed position and hyperpronation.[4]

Laboratory Studies

No laboratory studies are indicated in patients with isolated wrist injury.

Imaging Studies

Prehospital Care

The injured extremity should be splinted gently from above the elbow to the hand to prevent additional injury from inadvertent manipulation.

As with all trauma, address the possibility of additional injuries. Attend to ABCs, and use spine precautions if indicated by history and mechanism.

Urgent reduction of fractures may be necessary when neurovascular status has been compromised. This should be completed in the prehospital setting only when estimated ED arrival is more than 6 hours after the time of injury.

Emergency Department Care

In the ED, obtain a thorough history. Exclude additional injuries, and, if warranted, provide a full trauma evaluation. Maintain gentle, temporary splinting when not directly examining the injured wrist.

Wrist fractures are managed by reduction and immobilization following administration of adequate anesthesia and analgesia. Such reductions are typically performed by emergency physicians or orthopedic surgeons.[9]

Prior to closed reduction and fixation but after a careful neurovascular examination, administer proper sedation/anesthesia for the following 2 reasons: (1) to reduce or eliminate discomfort to the patient and (2) to reduce muscle spasm and splinting, which allow easier reduction and stabilization.

Options for analgesia or anesthesia prior to closed reduction include parenteral narcotics, conscious sedation, local/regional blocks, and hematoma blocks. Oral analgesics are suitable only for those injuries that do not require manipulation.

Conscious sedation increasingly is becoming the method of choice as more emergency physicians become skilled in its use. Properly performed, conscious sedation provides excellent anesthesia and muscle relaxation and leaves the patient with little or no recall of the event.

Hematoma block is performed by inserting a needle into the area of the fracture, aspirating blood to confirm placement, and injecting local anesthetic. The skin should be well prepared to avoid introduction of bacteria into the fracture site. For either hematoma or regional blocks, 0.5% bupivacaine (Marcaine) is ideal because of its low toxicity and long duration of action. For hematoma blocks, 10 mL of 0.5% bupivacaine is injected into the hematoma and another 5 mL is injected around the site. Allow 10-15 minutes prior to attempting manipulation.

Brachial block, while providing excellent anesthesia, is best left to those skilled in its use.

Reduction and immobilization

Always assess and document neurovascular status before starting reduction. Accurate reduction of the fracture is essential to obtaining good functional results. Early reduction lessens morbidity and improves patient comfort. Anatomic reduction is obtained by manipulation and plaster fixation and confirmed by repeat radiographs, portable fluoroscopy, or bedside ultrasonography. Anatomic reduction of distal radius fractures, both Colles and Smith fractures, are difficult to judge clinically. Ang et al adds ultrasonography to the traditional approach and offers the clinician a noninvasive way to identify proper alignment prior to post reduction radiographs.[10] The method of immobilization varies with the specific injury involved.

Colles fracture

The 2 keys to successful reduction of the typical Colles fracture are as follows:

ED treatment includes application of a plaster sugar-tong splint with the wrist held in slight flexion, with slight ulnar deviation and pronation of the forearm.

Obtain postreduction radiographs; assess and document neurovascular status of the extremity after reduction. Document function of the median nerve and the sensory branch of the radial nerve.

Smith fracture

For proper reduction of a Smith fracture, the forearm must be supinated fully while the elbow is fixed by an assistant or with the aid of the Weinberg traction device.

Extend the wrist to 90° and fully supinate the forearm. Then, recreate the position of the hand at injury to relax the periosteal attachments. Move the hand into the hyperflexed position and reduce the fracture segment with traction at approximately negative 60° while moving the fragments into alignment along the volar aspect of the wrist, pushing the fragment upwards and backwards with the thumbs. The wrist is forced into ulnar deviation and dorsiflexion for reduction. This position is held until a plaster sugar-tong splint is placed.

These fractures are very difficult to hold in position, especially if dorsiflexion and ulnar deviation is lost during application of the plaster.

Postreduction radiographs and documentation of the neurovascular status of the extremity is the standard of care.

Volar and dorsal dislocations

For volar dislocations, the hand is hyperpronated. For dorsal dislocations, it is hypersupinated. A sugar-tong splint is then placed. For volar dislocations, the hand is splinted fully pronated, whereas for dorsal dislocations, the hand is splinted in supination.

Appropriate consultation by an orthopedist must follow within the next 48 hours.

Scaphoid fractures

The diagnosis of scaphoid fracture is often made on clinical suspicion alone.

Immobilize the wrist in all patients with documented or suspected fractures.

Place the injured extremity in either a short- or long-arm thumb spica case with the distal interphalangeal (DIP) joint of the thumb included. The length of the cast remains controversial; however, the long-arm thumb spica has been demonstrated to improve rotational stability. Orthopedic follow-up is required.

Other carpal fractures

Lunate fractures require a short-arm spica cast or splint with thumb immobilization.

Emergency treatment of capitate, trapezium, and trapezoid fractures consists of position of function and orthopedic consultation. The isolated triquetral avulsion fracture can be treated with splint immobilization for 3-6 weeks. Midcarpal and ulnar side wrist instability must be ruled out before assuming that this is the correct treatment. The clinical examination should include a lunate-triquetral shear test to rule out lunotriquetral interosseous ligament tears,[11] and midcarpal instability should be evaluated with an axial compression and ulnar deviation test.[12] If ligamentous instability is suspected, an MRI is indicated for further evaluation.

Fractures of the pisiform can be immobilized with a volar splint.

Injuries to the triquetrum are best treated with a sugar-tong splint.

Treatment of a hamate fracture involves a short-arm cast with the fourth and fifth MCP joints held in flexion.

Pronation and supination injuries

Management of wrist articular injuries exactly mirrors the mechanism of injury. For example, with pronation injuries, the hand is supinated with the elbow held flexed at 90°. With a supination injury, pronation corrects the defect.

Nerve injury

Upon presentation and after treatment, the ED physician must evaluate the neurovascular status of the extremity. Careful note must be taken of ulnar and median nerve function.

The ulnar nerve is often injured with closed fractures of the pisiform, triquetrum, hamate, and fourth and fifth metacarpals.

The motor branch of the ulnar nerve is the chief motor nerve of the hand. The sensory branch rarely is affected. Blunt trauma to the hypothenar eminence may result in contusion to the ulnar nerve, with resulting neurapraxia. If a large hematoma is present, it may be aspirated or surgically removed after appropriate consultation.

Median nerve injury, including traumatic carpal tunnel syndrome, is manifested by sensory disturbances in the thumb and index and long fingers.

Median nerve injury is associated with Colles fractures, Smith fractures, perilunate dislocations, and carpal bone injuries. Compression along the volar ligament results in pain and paresthesias along the median nerve. Only late in this disorder does the thenar eminence exhibit muscle atrophy.

Recognition of the injury and referral for consultation is the aim of the ED physician. If an acute injury is secondary to a displaced fracture, and physical signs indicate compression of the nerve, acute reduction of the displaced fracture is indicated.

Consultations

Obtain immediate consultation with a hand specialist or orthopedic surgeon for open or unstable fractures and those requiring fixation.

All other fractures should have adequate orthopedic follow-up care to ensure proper wrist function.

Medication Summary

Drugs used to treat fractures include analgesics and anxiolytics. In addition, proper antibiotics must be administered for open fractures.

Fentanyl (Duragesic)

Clinical Context:  Short duration (30-60 min), ease of titration, and rapid and easy reversal by naloxone make this an excellent choice for pain management and sedation.

Morphine sulfate (Duramorph, Astramorph, MS Contin)

Clinical Context:  DOC for narcotic analgesia because of its reliable and predictable effects, safety, and ease of reversibility with naloxone. Administered IV, may be dosed in a number of ways and commonly is titrated until desired effect obtained.

Propoxyphene/acetaminophen (Darvocet N-100)

Clinical Context:  Propoxyphene was withdrawn from the US market. Drug combination indicated for treatment of mild to moderately severe pain.

Acetaminophen and codeine (Tylenol #3)

Clinical Context:  Drug combination indicated for treatment of mild to moderately severe pain.

Hydrocodone bitartrate and acetaminophen (Vicodin ES)

Clinical Context:  Drug combination indicated for relief of moderately severe to severe pain.

Class Summary

Pain control is essential to quality patient care. It ensures patient comfort, promotes pulmonary toilet, and aids physical therapy regimens. Most analgesics have sedating properties that benefit patients who have sustained traumatic injuries.

Propoxyphene products were withdrawn from the United States market on November 19th, 2010. The withdrawal was based on new data showing QT prolongation at therapeutic doses. For more information, see the FDA MedWatch safety information.

Lorazepam (Ativan)

Clinical Context:  Sedative hypnotic in benzodiazepine class that has short onset of effect and relatively long half-life. By increasing action of GABA, a major inhibitory neurotransmitter, may depress all levels of CNS, including limbic and reticular formation.

Alprazolam (Xanax)

Clinical Context:  Indicated for treatment of anxiety and management of panic attacks.

Midazolam (Versed)

Clinical Context:  DOC for acute sedation/anxiety as adjuvant for reduction of acute fracture/dislocations. Titratable effect and anterograde amnesia for 1-2 h make this an ideal agent. Onset of action within 2 min, and effective duration of action 30 min IV and 45 min IM.

Class Summary

Patients with painful injuries usually experience significant anxiety. Anxiolytics allow a smaller analgesic dose to achieve the same effect.

Further Inpatient Care

Further Outpatient Care

Inpatient & Outpatient Medications

Transfer

When proper orthopedic care is not available at a site, transfer the patient to a higher-level care facility once neurovascular stability has been addressed adequately.

Deterrence/Prevention

Since a large number of wrist fractures occur secondary to in-line skating accidents and other sporting activities, encourage wrist protection during these sports.

Complications

Prognosis

Prognosis depends on many variables, including the following:

Author

Bryan C Hoynak, MD, FACEP, FAAEM, Associate Clinical Professor of Emergency Medicine, University of California at Irvine School of Medicine; Director of Emergency Services, Chairman of Division of Emergency Medicine, Placentia-Linda Hospital

Disclosure: Nothing to disclose.

Coauthor(s)

Laura Hopson, MD, Staff Physician, Assistant Professor, Clinical Track, Department of Emergency Medicine, University of Michigan

Disclosure: Nothing to disclose.

Specialty Editors

Michelle Ervin, MD, Chair, Department of Emergency Medicine, Howard University Hospital

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

Tom Scaletta, MD, Chair, Department of Emergency Medicine, Edward Hospital; Past-President, American Academy of Emergency Medicine

Disclosure: Nothing to disclose.

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD, Attending Physician, Department of Emergency Medicine, Cambridge Health Alliance, Division of Emergency Medicine, Harvard Medical School

Disclosure: WebMD Salary Employment

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Lateral radiograph of the wrist illustrating volar dislocation of the lunate.

Lateral radiograph of the wrist illustrating volar dislocation of the lunate.