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 bones

The 8 carpal bones are arranged in 2 rows to form a compact, powerful unit. Each is cuboid with 6 surfaces; 4 are covered with cartilage to articulate with the adjacent bones, and 2 are roughened for ligamentous attachment. The proximal carpal row contains the scaphoid (also called the navicular), lunate, triquetrum, and pisiform. It articulates proximally with the radius and the triangular cartilage. The ulna does not articulate directly with the carpus but is separated from the triquetrum by a triangular fibrocartilage, which acts as a stabilizing structure. The distal carpal row contains the trapezium, trapezoid, capitate, and hamate and articulates with the 5 metacarpals.

Joints and ligaments

The wrist includes 5 large joint cavities in addition to the intercarpal joint spaces: the radiocarpal joint, the distal radio-ulnar joint (DRUJ), the midcarpal joint, the large carpometacarpal joint (between the carpus and the second, third, fourth, and fifth metacarpals), and the small carpometacarpal joint (between the first metacarpal and the trapezium).

The strength of the wrist is dependent on the integrity of the ligamentous network, which links the carpus together. The volar carpal ligament extends from the trapezium to the hook of the hamate and forms the anterior roof of the osseous/fibrous tunnel. Within this tunnel lie the tendons for the finger flexors and the median nerve. Encroachment on this space results in median nerve compression. The second and third metacarpals are fixed at their bases and are immobile.

The muscles of the hand originate primarily in the forearm and pass over the wrist. The only muscle with insertion into the wrist is the flexor carpi ulnaris, which inserts into the pisiform, a small sesamoid bone.

Movement of the wrist is 80° in flexion, 70° in extension, 30° in ulnar deviation, and 20° in radial deviation. Pronation and supination occur at the radial-ulnar articulation in the forearm not at the wrist.

Neurovascular anatomy

The wrist comprises several important neurovascular structures. The deep branches of the ulnar nerve and the ulnar artery run deep to the flexor carpi ulnaris tendon through the Guyon canal. They pass near the hamate and capitate and can be involved with injuries to these structures. The ulnar nerve innervates the intrinsic muscles of the hand, including the hypothenar muscles, interossei, ulnar lumbricals, and adductor pollicis.

The median nerve lies between the flexor carpi radialis and the palmaris longus tendon in the carpal tunnel. The median nerve innervates the thenar compartment and provides sensation to the radial portion of the hand. Any displacement of the normal anatomic alignment of the wrist can injure this nerve.

The blood supply to the hand is via the radial and ulnar arteries, which form the dorsal palmar arch. The scaphoid bone receives its blood supply from the distal part of this arch, which is prone to injury.

Surface anatomy

Several anatomic landmarks are important to recognize when performing an accurate and thorough examination of an injured wrist. The anatomic snuffbox lies on the radial aspect of the dorsum of the wrist. It is defined in the ulnar aspect by the tendon of the extensor pollicis longus and radially by the tendons of the extensor pollicis brevis and abductor pollicis longus. The floor is composed of the scaphoid proximally and the trapezium distally. The anatomic snuffbox is most easily observed with the thumb held in a position of extension with the wrist slightly deviated in the radial aspect.

The next landmark is the Lister tubercle, a bony prominence over the dorsum of the distal radius. With the hand held in neutral, a line drawn between the third metacarpal and the Lister tubercle will cut through the capitate distally and the lunate proximally. Just distal to the ulnar styloid, the triquetrum can be palpated. At the base of the hypothenar eminence on the volar aspect of the wrist lies the pisiform. The hook of the hamate can be felt with deep palpation of the palm approximately 1 cm distant from the pisiform along a line pointing to the index metacarpophalangeal (MCP) joint.

Carpal fractures and dislocations

Scaphoid fracture

The scaphoid bone is based in the proximal row of carpal bones but extends into the distal row, making it more vulnerable to injury than the other carpal bones. It is the most frequently injured carpal bone, accounting for 60-70% of all carpal fractures. It is also a frequently missed injury, as approximately 10-15% of fractures are not demonstrated on routine radiographs. More than three fourths of all fractures occur at the narrow midportion or waist of the scaphoid. Because blood is supplied to the scaphoid along its dorsal surface near its waist, fractures at this location potentially compromise flow to the proximal portion of the bone. As a result, avascular necrosis is a serious complication of this injury.

Hyperextension of the wrist is the most common mechanism of scaphoid fracture either by a fall on an outstretched hand or by a direct blow to the palm. Often, the wrist has some degree of radial deviation. Hyperextension causes the radial styloid to impinge on the waist of the scaphoid as it crosses between the 2 rows of carpal bones. Scaphoid fractures are often associated with other injuries of the wrist, including dislocation of the radiocarpal joint, dislocation between the 2 rows of carpal bones, fracture-dislocation of the distal end of the radius, fracture at the base of the thumb metacarpal, and dislocation of the lunate.

Lunate fracture

Although a relatively uncommon injury, fracture of the lunate is the third most frequent carpal bone fracture. The lunate is located in the center of the proximal carpal row and articulates with the radius. Fractures can occur in any orientation, and diagnosis often requires a high degree of clinical suspicion.

Fractures of the lunate most often result from hyperextension of the wrist or impact of the heel of the hand on a hard surface. This injury can also occur from a fall on the outstretched hand. Patients usually present with weakness of the wrist and pain aggravated with compression along the third digital ray.

Triquetrum fracture

The triquetrum is one of the more commonly injured carpal bones. The triquetrum is the second most injured carpal bone associated with sports injuries.[1] It lies on the ulnar aspect of the proximal row of carpal bones. Strong ligaments attach the triquetrum to the lunate, which adjoins its radial aspect. In addition, the triquetrum is connected to the distal ulna by a triangular fibrocartilage complex.

The most common mechanism of injury is forced hyperextension of the wrist with ulnar deviation. In this position, the triquetrum is forced against the ulnar styloid, generating a shearing force that results in avulsion of ligaments and a dorsal chip fracture of the triquetrum. A second, less common, mechanism is a direct blow to the dorsum of the hand, which causes a transverse fracture through the body of the triquetrum. This is a high-energy injury and is frequently associated with injury to other carpal bones.

Capitate fracture

The capitate is the largest carpal bone and articulates with 7 other bones, including the second, third, and fourth metacarpals. It is located in the center of the distal row of carpal bones. Axial motion of the third metacarpal depends on a functional articulation with the capitate. These fractures account for fewer than 10% of carpal bone injuries and usually are transversely oriented. Blood supply to the capitate enters its dorsal segment and is often disrupted following fracture, resulting in avascular necrosis.

Two mechanisms of injury are common in capitate fractures. Like most carpal bones, the capitate can be injured by a fall on an outstretched hand with forced dorsiflexion and a degree of radial deviation of the wrist. In this position, the dorsal lip of the radius is able to strike the body of the capitate. A second mechanism is a direct blow or crush injury to the dorsum of the wrist

Hamate fracture

The hamate occupies the ulnar aspect of the distal row of carpal bones. It is an unusually shaped bone, with a hook that protrudes toward the palmar surface and serves as an attachment site for several ligaments. The most common injury pattern is a fracture through the base of this hook. This is an uncommon injury. Clinical examination is very important as plain radiographs often miss this fracture. The hook of the hamate is found by palpating the pisiform bone and then moving in an oblique line toward the index finger metacarpophalangeal joint about 2 cm. Reproducible pain indicates a suspected hamate fracture.[1] If plain films are normal, a CT scan has 100% sensitivity, 94.4% specificity, and 97.2% accuracy.[2, 3]

The hook of the hamate is typically fractured by a direct blow when the hand is held slightly dorsiflexed and with some degree of ulnar deviation. A common history is that a golf club, racket, or bat struck a stationary object during full swing, resulting in immediate pain over the hypothenar eminence. This pain is exacerbated by any type of gripping activity.

Trapezium fracture

Fractures of the trapezium are rare, comprising no more than 5% of fractures of the carpal bones. Fractures of the body of the trapezium result when an adducted thumb is forced onto the articular surface of the carpal bone. In addition, forced radial deviation of the thumb may result in small avulsion fractures due to capsular strain.

Trapezoid fracture

Fractures of the trapezoid are rare, accounting for fewer than 1% of carpal bone fractures. The mechanism of injury is axial loading along the line of the second metacarpal.

Pisiform fracture

The pisiform is a sesamoid bone within the tendon of the flexor carpi ulnaris. It articulates only with the triquetrum and lies near the deep ulnar nerve and artery. Fractures are rare. The pisiform is typically injured by a fall on an outstretched hand in a dorsiflexed position, with the impact on the hypothenar eminence.

Lunate and perilunate dislocation

Dislocations of the carpal bones are usually the result of extreme flexion or extension of the wrist. The type of dislocation or fracture-dislocation produced by these mechanisms depends on the direction and intensity of the injuring force and the position of the hand in relation to the forearm at the moment of impact. The integrity of the lunate-capitate relationship is the most crucial factor in all dislocations of the wrist. The resulting lesions are related directly to disruption or preservation of this articulation.

These rare injuries may have a poor outcome if not recognized in a timely fashion. The exact diagnosis can often be difficult to determine by radiography. Four specific projections can help when taking comparison radiographs: anteroposterior (AP), lateral, 45° of pronation, and 45° of supination. An accurate history can be a clue to the diagnosis. Knowledge of the exact mechanism of injury can allow prediction of the resulting dislocation.

Extension injuries

Dorsal perilunate or volar lunate dislocation is caused when the hand is forced into extension such as in a fall on the outstretched hand. Commonly, a fracture or fracture-dislocation of the scaphoid complicates the dorsal perilunate dislocation.

Flexion injuries

Dorsal dislocation of the lunate can occur when the hand and carpus are hyperflexed, as occurs with a fall onto the back of the hand. The upward force generated when the hand contacts the ground, together with the downward force acting through the radius, forces the capitate to rotate anteriorly and drive the lunate backward into a dorsal position.

With a volar perilunate dislocation, the lunate remains in its normal position relative to the radius and the rest of the carpus dislocates anteriorly. This dislocation is often associated with a scaphoid fracture.

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.

Extension fractures of the distal radius

Multiple classification schemes have been developed for extension injuries of the distal radius. These tend to be complex and cumbersome. In general, however, the greater the degree of displacement and comminution, the more severe the injury. Extension of a fracture into the radiocarpal or the DRUJ is also a marker for a more severe injury. More complex fractures tend to be more unstable.

Extension fractures result from a fall on an outstretched pronated hand with the impact on the palm and subsequent forced dorsiflexion or hyperextension. On striking a hard surface, the hand becomes fixed while the momentum of the body produces the following 2 forces: twisting force that causes excessive supination of the forearm, and compression force that acts vertically through the carpus to the radius.

The lunate acts as the apex of a wedge against the articular surface of the radius and causes injuries that vary by the age of the patient. Very young children usually sustain a greenstick fracture of the distal radius, with or without an associated fracture of the distal ulna. In adolescents, the lower epiphysis separates, with dorsal displacement or crushing. In adults, fracture occurs within 1 inch of the carpus. The distal fragment is usually displaced upward and backward. In all age groups, the fracture may be complicated by injury to the median nerve or the sensory branch of the radial nerve, by fracture of the scaphoid or dislocation of the lunate, or both.

If a concomitant supinating force is applied, often the distal ulna also fractures. Approximately 60% of distal radius fractures are associated with fracture of the ulnar styloid. Approximately 60% of ulnar styloid fractures also have an associated fracture of the ulnar neck.

Colles fracture is the most common extension fracture pattern. The term is classically used to describe a fracture through the distal metaphysis approximately 4 cm proximal to the articular surface of the radius. However, now the term tends to be used loosely to describe any fracture of the distal radius, with or without involvement of the ulna, that has dorsal displacement of the fracture fragments.

Colles fractures occur in all age groups, although certain patterns follow an age distribution. In elderly individuals, because of the relatively weaker cortex, the fracture is more often extra-articular. Younger individuals tend to require a relatively higher-energy force to cause the fracture and tend to have more complex intra-articular fractures. In children with open physes, an equivalent fracture is the epiphyseal slip. This is a Salter I or II fracture with the deforming forces directed through the weaker epiphyseal plate.

Flexion fractures of the distal radius (reverse Colles fracture/Smith fracture)

A Smith fracture is relatively uncommon compared with the Colles fracture. This term is used loosely to refer to any fracture of the distal radius, with or without involvement of the ulna, that has volar displacement of the distal fragments. A true Smith fracture comprises a fracture of the entire thickness of the distal radius, 1-2 cm above the wrist. The lower end of the radius is displaced forward and upward.

This fracture is typically caused by a fall onto a supinated forearm or hand with generation of a hyperflexion force. On striking the ground, the hand locks in supination while the body's momentum forces the hand into hyperpronation. A direct blow to the dorsum of the wrist with the hand in flexion and forearm pronated can also produce a similar fracture pattern. Another mechanism is punching with the wrist in a slightly flexed position.

Pseudocarpal injuries

Pseudocarpal injuries are those that involve the distal end of the radius and ulna just proximal to the carpus and manifest with clinical signs that mimic carpal bone injuries. Specifically, these include articular disk injuries of the wrist, dislocations of the inferior radioulnar joint, and traumatic dislocation of the distal end of the ulna. These are rare injuries and require orthopedic consultation for definitive management. Recognition of these injuries in the ED is important if functional outcome is to be optimized.

Wrist articular injuries

Injury to the articular disk of the wrist occurs from multiple mechanisms. It usually coexists with other more common injuries, but isolated injuries to the articular disk can occur. The most common pathologic defect is tearing of the disk from its attachment at the margin of the ulnar notch of the radius. The primary function of the triangular disk of the wrist is to prevent lateral displacement of the ulna. The most common mechanism of injury is dorsiflexion and pronation of the hand. Less frequently, extreme hyperextension and supination may cause injury. Volar or dorsal dislocation of the head of the radius may coexist.

The Barton or push-off fracture is an intra-articular injury involving the dorsal or volar articular surface of the radius. It is an uncommon fracture pattern. This type of fracture is generally observed with extreme dorsiflexion of the wrist with concomitant exertion of a pronating force.

Traumatic dislocation of the distal ulna

Dislocation or subluxation of the distal ulna is most often associated with fractures of the radius. However, acute traumatic dislocation/subluxation of the head of the ulna without fracture can occur and often is not recognized in the ED.

The ulnar head may be displaced anteriorly or posteriorly, depending on the mechanism of injury. Extreme extension and pronation of the hand produces a dorsal dislocation of the head of the ulna. Extreme extension and supination of the hand produces a volar dislocation of the ulnar head.

Radial styloid fracture

A Hutchinson fracture, an isolated fracture of the radial styloid, is typically caused by a direct blow to the radial aspect of the wrist. It may also be referred to as "chauffeur's fracture" or "backfire fracture," as it initially was described in individuals struck by the hand crank on early automobiles when the engine suddenly backfired during starting.

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]

Imaging Studies

Routine radiographs of the wrist include AP, lateral, and oblique views. These are adequate to identify most fractures. Look for evidence of displacement of carpal bone fractures because this often indicates the need for operative intervention.

When evaluating a fracture of the distal radius or ulna, carefully check the normal anatomic alignments. The radiocarpal joint viewed on the lateral film normally has 11° of palmar angulation with a range of 1-23°. Ulnar angulation on the AP film is normally 15-30°. The radial length, which is the distance between the ulnar aspect of the distal radius and the tip of the radial styloid, normally measures 11-12 mm.

Look for an associated ulnar styloid fracture and involvement of the radiocarpal joint or DRUJ. If the radius appears to be angulated and/or displaced significantly, maintain a high degree of suspicion for a concomitant fracture of the ulna.

Scaphoid fractures often are not seen on routine radiographs. Scaphoid views taken with the wrist deviated toward the ulna and slightly supinated may help to demonstrate a fracture. The approximately 10-15% of fractures that are occult may be apparent on plain films after 10-14 days as bony reabsorption occurs at the fracture site. While not appropriate for ED workups, CT scans and bone scans as early as 3 days after injury may aid in the diagnosis.

Bone scan or MRI may be necessary to detect occult fractures not visualized on plain radiographs. MRI is superior to repeat radiographs for detecting occult scaphoid fracture[5] and is the criterion standard for detecting scaphoid fractures, with a sensitivity of 95-100% and specificity approaching 100%.[6, 7, 8]

In a systematic review of 75 studies, MRI was determined to be the most accurate imaging test to diagnose scaphoid fractures in ED patients with no evidence of fracture on initial x-rays. If MRI was unavailable, CT was adequate to rule in scaphoid fractures but inadequate for ruling out scaphoid fractures. Both MRI and CT shared the added benefit of identifying alternative etiologies for posttraumatic wrist pain. Scaphoid fractures are the most common carpal fracture, representing 70% of carpal bone fractures.[9]

In 124 patients who had wrist trauma and displayed typical clinical symptoms suspicious of an acute scaphoid fracture, multidetector computed tomography (MDCT) was shown to be superior to radiography. Conventional radiography detected 34 acute fractures of the scaphoid, whereas MDCT revealed a total of 42 scaphoid fractures.[10]

Injuries to the hamate and trapezium can be visualized best with a carpal tunnel view.

Like scaphoid injuries, injuries to the lunate and capitate may not be well visualized on plain films, and CT scan may be required.

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.[11]

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.[12] 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,[13] and midcarpal instability should be evaluated with an axial compression and ulnar deviation test.[14] 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 Outpatient Care

Distal radius fracture:

Scaphoid fracture: Treatment in a spica cast for 12 weeks results in healing in 90% of these fractures.

Lunate fracture: Most heal in a spica cast for 10-12 weeks.

Further Inpatient Care

Open fracture and/or joint capsule injury require the following treatments:

Distal radius fracture: Look for acute carpal tunnel syndrome.

Inpatient & Outpatient Medications

Oral analgesics should provide sufficient pain relief.

To reduce pain and edema, apply ice to the injured region for the first 48 hours.

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

The anatomy of the scaphoid bone makes it vulnerable to secondary injury. It is supplied by a single blood vessel that penetrates the cortex near the waist of the scaphoid. Scaphoid fractures are prone to delayed healing and avascular necrosis. The more proximal the fracture, the more common these complications. Missed diagnosis and lack of appropriate immobilization increase this risk. Missed diagnosis or nonunion predisposes an individual to development of potentially debilitating radiocarpal arthritis.

Keinböck disease is osteonecrosis and subsequent collapse of the proximal portion of the lunate resulting in pain, loss of function, and carpal bone instability. The exact mechanism for development of this condition is disputed, with theories ranging from repetitive microtrauma to avascular necrosis from a single injury. As the lunate receives its blood supply from a single distal blood vessel in 20% of individuals, these patients may be predisposed to avascular necrosis and nonunions. Younger patients, typically those younger than 16 years, tend to have better functional outcomes from lunate injuries than older patients.

Complications from a capitate fracture include nonunion and avascular necrosis as, like the scaphoid, it is dependent on a single blood vessel, which enters from its distal aspect. Posttraumatic arthritis is a frequent complication. Fibrosis of surrounding tissues after injury may result in carpal tunnel syndrome.

Fractures through the base of the hook of the hamate are frequently displaced by the forces of the hook's multiple ligamentous attachment. Nonunion is a frequent complication and may necessitate surgical excision of the hook to relieve pain from grasping activities.

Acutely, a Colles fracture has several potential complications. These include compression or contusion of the median and/or ulnar nerves. An acute carpal tunnel syndrome may result from swelling. The flexor tendons may be injured by the bony fragments. Excessive swelling can result in compartment syndromes. Comminuted or severely displaced fractures may be unstable, resulting in a loss of reduction and requiring repeated attempts or surgical intervention.

Long term, the wrist may have radial shortening and angulation deformity, limiting range of motion. Some individuals experience chronic pain, particularly with supination. Adhesions may limit mobility of the flexor tendons. As with all fractures, malunions or nonunions may complicate healing. With comminuted intra-articular fractures, more than two thirds may be complicated by the late development of arthritis.

Reflex sympathetic dystrophy complicates some 3% of distal radius fractures. This controversial diagnosis is a syndrome of paresthesias, pain, stiffness, and changes in skin temperature and color.

Smith (reverse Colles) fracture may result in complications similar to those of Colles fracture.

Radiocarpal fracture-dislocation may cause entrapment of tendons or of the ulnar nerve and/or artery.[15]

Hutchinson fracture may result in scapholunate dislocation, osteoarthritis, or ligament damage.

Ulnar styloid fracture often results in nonunion.

Prognosis

Prognosis depends on many variables, including the following:

Patient Education

For patient education resources, see the Breaks, Fractures, and Dislocations Center, as well as Wrist Injury and Broken Hand.

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, Department of Emergency Medicine, University of Michigan

Disclosure: Nothing to disclose.

Specialty Editors

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

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Trevor John Mills, MD, MPH, Chief of Emergency Medicine, Veterans Affairs Northern California Health Care System; Professor of Emergency Medicine, Department of Emergency Medicine, University of California, Davis, School of Medicine

Disclosure: Nothing to disclose.

Acknowledgements

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

Michelle Ervin, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, National Medical Association, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

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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.

During a soccer game, a 12-year-old boy fractured his wrist when falling on an outstretched hand. The fracture was reduced with traction and splinting under moderate sedation. Good postreduction alignment was achieved.