Wrist Dislocation in Emergency Medicine 

Updated: Feb 13, 2015
Author: Michael S Beeson, MD, MBA, FACEP; Chief Editor: Trevor John Mills, MD, MPH 

Overview

Background

Carpal dislocations represent a continuum of wrist injury that can lead to lunate or perilunate dislocation. The lunate cup commonly is directed in a volar direction in dislocation because of the mechanism of the injury. Perilunate dislocations result from dislocation of the distal carpal row.[1] The capitate normally rests within the lunate cup, as seen on a lateral view. With perilunate dislocations, the capitate is seen most commonly as dorsal, but it also may be volar to the lunate on lateral x-ray evaluation. As a result of the stresses involved, scaphoid fractures often accompany perilunate dislocation.[2, 3] Carpal instability may take many forms and represents a spectrum of injury including scapholunate dissociation, lunate and perilunate dislocations, scaphoid fracture, and other intercarpal instabilities. A lunate dislocation is shown in the radiograph below.

Dislocations, wrist. Lateral view of a lunate disl Dislocations, wrist. Lateral view of a lunate dislocation, with the classic teacup sign.

For more information, see Medscape's Orthopaedics Resource Center.

Pathophysiology

The mechanism of injury is usually a fall onto an outstretched hand with hand rotation, which may lead to a variety of injuries. These injuries range from scapholunate strain to carpal dislocation, with scaphoid fracture at the end of the spectrum. Unfortunately, most of these injuries are not diagnosed in the ED. The injury may lead to chronic pain and instability of the wrist.[4, 5, 6]

Epidemiology

Frequency

United States

Incidence of wrist injuries is estimated as 2.5% of ED visits. Wrist dislocations represent a very small portion of these visits. Because of this small proportion of wrist dislocations, they can be easily missed on initial presentation to the ED.

Mortality/Morbidity

The morbidity of wrist dislocations is tied to the frequently missed diagnosis of lunate or perilunate dislocation in the ED.[7] Often, patients are not diagnosed with these injuries until weeks following the initial injury.

Many patients with undiagnosed wrist dislocation have chronic pain.

Carpal instability, including radiocarpal instability, is a frequent complication.

Avascular necrosis of the lunate, Kienbock disease, is a potential complication of lunate dislocation.

 

Presentation

History

Patients usually present to the ED fairly soon after a fall onto an outstretched hand.

The mechanism of injury is ulnar deviation of the wrist coupled with dorsiflexion.

The resulting intercarpal supination places great stress on the carpals. The result can be a lunate or perilunate dislocation.[1]

Often, the only symptom is wrist pain.

Frequently, lunate and perilunate dislocations are not recognized at the time of the initial ED visit.[7] This emphasizes the need to consider lunate or perilunate dislocation when a patient returns to the ED a second or third time for what appears to be chronic wrist pain following an injury.

Physical

The patient may have diffuse pain on palpation that is difficult to distinguish from other causes of wrist pain, including scapholunate strain, scaphoid fracture, triangular fibrocartilage complex tears, and other disorders.

Causes

Carpal stability is based on the lunate as the central anchor for the proximal and distal carpal rows.

The lunate is apposed to the radius, and the capitate rests within the lunate cup.

The proximal row of carpals is connected by interosseous ligaments.

Carpal stress is characterized as radial or ulnar, with some degree of axial loading. This stress is translated to all bones.

Ligamentous injury results in a spectrum of injuries, including lunate and perilunate dislocations.

The lunate-scaphoid ligaments may not be disrupted; if this is the case, scaphoid fracture may occur.

 

DDx

 

Workup

Imaging Studies

Plain x-rays of the wrist, both anteroposterior (AP) and lateral views, are essential to diagnose wrist dislocations (as well as other carpal instabilities).

On an AP view (shown below), 2 arcs should be identified. The first arc consists of the radiocarpal row, which should be smooth and continuous. Disruption is suggestive of a lunate dislocation.

Dislocations, wrist. Anteroposterior (AP) view of Dislocations, wrist. Anteroposterior (AP) view of a lunate dislocation.

The second arc consists of the midcarpal row, which also should be smooth and continuous. Disruption of this arc is suggestive of a perilunate dislocation.

The appearance of the lunate is important on the AP view. Normally, the lunate is quadrangular. With lunate dislocations, it becomes triangular. This may be an additional clue to dislocation.

On the lateral view (shown below), visualize the column, which consists of the radius, lunate, and capitate. The lunate should lie within the radius cup and the capitate should rest within the lunate cup. Loss of this normal column implies lunate or perilunate dislocation.

Dislocations, wrist. Lateral view of a lunate disl Dislocations, wrist. Lateral view of a lunate dislocation, with the classic teacup sign.

Stress x-rays of the wrist may be necessary to demonstrate intercarpal ligamentous instability when no evidence of wrist dislocation is apparent on plain films.

Stress x-rays obtained with radial and ulnar deviation of the hand may demonstrate scapholunate dissociation.

 

Treatment

Prehospital Care

Prehospital care includes assessment for other injuries that may accompany the wrist injury.

If no other injuries are identified, splint the wrist.

Patients may be transported in their private vehicles, but the prehospital provider must emphasize the potential seriousness of the injury.

Under no circumstances should a prehospital provider attempt a reduction of a suspected wrist dislocation. It may be a distal radius fracture, which requires significant care to reduce.

Emergency Department Care

Patients with wrist injuries have an entire spectrum of possible injuries that represent potential disability.

Although no specific fracture or dislocation may be seen on x-ray, carpal instability still may be present.

Therefore, splint with plaster even if no injury is found on x-ray.

Carefully splint with AP splints to the fingers until a hand specialist can evaluate the injury.

Consultations

Patients in whom a wrist dislocation has been identified require referral to a hand specialist who is either an orthopedic or plastic surgeon, depending on local custom.

Wrist dislocations may be reduced by emergency physicians, but only after consulting with the hand specialist.

The patient's own primary care physician may follow up, but it is important to stress to the primary care physician the need for hand specialist referral.

 

Medication

Medication Summary

The goals of pharmacotherapy are to reduce morbidity and prevent complications.

Analgesics

Class Summary

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

Acetaminophen and codeine (Tylenol #3)

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

Oxycodone and acetaminophen (Percocet)

Drug combination indicated for relief of moderately severe to severe pain. DOC for aspirin-hypersensitive patients.

Oxycodone and aspirin (Percodan)

Drug combination indicated for relief of moderately severe to severe pain.

Hydrocodone bitartrate and acetaminophen (Vicodin ES)

Drug combination indicated for relief of moderately severe to severe pain.

Acetaminophen (Tylenol, Panadol, Aspirin-free Anacin)

DOC for pain in patients with documented hypersensitivity to aspirin or NSAIDs, those with upper GI disease, or those taking oral anticoagulants.

Nonsteroidal anti-inflammatory agents (NSAIDs)

Class Summary

These agents are used most commonly for the relief of mild to moderately severe pain. Although the effects of NSAIDs tend to be patient specific, ibuprofen is usually the DOC for initial therapy. Other options include flurbiprofen, ketoprofen, and naproxen.

Ibuprofen (Ibuprin, Advil, Motrin)

DOC for treatment of mild to moderately severe pain if no contraindications. Inhibits inflammatory reactions and pain, probably by decreasing activity of enzyme cyclooxygenase, which inhibits prostaglandin synthesis.

Ketoprofen (Oruvail, Orudis, Actron)

Used for relief of mild to moderately severe pain and inflammation. Administer small dosages initially to patients with small body size, elderly persons, and those with renal or liver disease. Doses higher than 75 mg do not increase its therapeutic effects. Administer high doses with caution and closely observe patient.

Flurbiprofen (Ansaid)

Has analgesic, antipyretic, and anti-inflammatory effects. May inhibit cyclooxygenase enzyme, inhibiting prostaglandin biosynthesis.

Naproxen (Anaprox, Naprelan, Naprosyn)

Used for relief of mild to moderately severe pain. Inhibits inflammatory reactions and pain by decreasing activity of enzyme cyclooxygenase, decreasing prostaglandin synthesis.

 

Follow-up

Further Outpatient Care

Patients with lunate or perilunate dislocations, if reduced in the ED, may safely be discharged home with careful warnings of the potential for compartment syndrome, pain, and other postinjury conditions.

Close follow-up must be arranged with a hand specialist.

Further Inpatient Care

Admission is not indicated for isolated wrist dislocation.

Inpatient & Outpatient Medications

Because of the severity of pain, narcotic pain medication often is required for the first 3 days.

Transfer

Transfer is required if the emergency physician is unable to achieve reduction and a hand specialist is not available to evaluate the injury.

Complications

Vascular complications are unusual but may occur if an associated fracture is present, particularly of the distal radius.

Soft-tissue complications include carpal ligamentous disruption, which results in carpal instability.

Kienbock disease, avascular necrosis of the lunate, may occur following lunate dislocations, even if there is successful reduction in the ED.

Prognosis

Many patients who sustain lunate or perilunate dislocation develop chronic wrist pain or wrist instability.

Remember that lunate and perilunate dislocations are part of a continuum of injury that arises from significant carpal ligamentous injury. This often results in chronic carpal instability.

Patient Education

For excellent patient education resources, visit eMedicine's Breaks, Fractures, and Dislocations Center. Also, see eMedicine's patient education article, Wrist Injury.