Avoiding Common Errors in the Emergency Department - Book 2

281

KNOW THE RADIOGRAPHIC SIGNS
OF SCAPHOLUNATE DISLOCATION

NICHOLAS ABRAHAM, MD AND STUART SWADRON, MD,
FRCPC

Scapholunate dislocation or dissociation (SLD) is widely recognized as the
most common ligamentous injury of the wrist. The injury occurs in isolation
as well as with a variety of fracture-dislocation patterns, including up to 30%
of intra-articular distal radius or carpal fractures. Mechanism of injury is
most commonly a direct impact force to the hand and wrist over the thenar
eminence with the wrist positioned in extension, ulnar deviation, and carpal
supination. This results in an acute tear of the scapholunate ligament creating
a gap between the lunate and the proximal pole of the scaphoid. Additionally,
the injury can coexist with a rupture of the radioscapholunate ligament
resulting in palmar rotation (or rotary subluxation) of the scaphoid.

SLD is frequently missed on initial presentation and can be very subtle,
especially when in isolation or associated with other more severe injuries. It
is inherently more difficult to detect because it is often present without a
fracture. Clinically, patients present with varying degrees of grip weakness,
limited motion, dorsoradial swelling, and point tenderness. These symptoms
and signs are often associated with a clunking or snapping sensation with
wrist movement. The scaphoid tilt test is valuable to determine the presence
of injury. A positive test has been described as diagnostic when performed
by an experienced clinician.

SCAPHOID TILT TEST

1) Place four fingers behind the radius with your thumb on the tuberosity

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of the scaphoid.
2) Use your other hand to passively move from ulnar to radial deviation.

When the hand is ulnar deviated, the scaphoid is in an extended position in
line with the forearm, while in radial deviation, the scaphoid is flexed.
Applying pressure to the tuberosity while moving the hand from ulnar to
radial deviation prevents the scaphoid from flexing. If the scapholunate
ligaments are disrupted, the proximal pole moves dorsally out of alignment
with the radius, often inducing pain on the dorsoradial aspect of the wrist.
When the applied pressure is released, the scaphoid self-reduces over the
dorsal rim of the radius inducing the typical clunking or snapping as
described above.

Once suspected, the diagnosis is confirmed by the presence of one or
more features seen on radiographs. Emergency physicians should know the
carpal bones and have a standardized routine for evaluating wrist films.
While many mnemonics exist, one example is “So Long To Pinky, Here
Comes The Thumb” for the scaphoid, lunate, triquetrum, pisiform, hamate,
capitate, trapezoid, and trapezium, respectively. On the anteroposterior (AP)
view, the clinician should look for widening of the scapholunate joint space.
Examining this space should be a routine part of a clinician’s wrist film
reviewing process. A measurement of >3 mm is pathognomonic, named the
“Terry Thomas” sign after the popular 1960s comedian with a trademark gap
in his front teeth. More recently, this gap has been dubbed the “David
Letterman” sign after the more contemporary comedian. The second sign to
be aware of is the cortical ring sign, formed by a foreshortened scaphoid, due
to rotary subluxation and volar tilt, causing a visible ring-shaped double
density at its distal pole (see Figure 281.1). The lateral view should also be
closely examined to ensure that the radius, lunate, and capitate form a
straight line. The proximal portion of the scaphoid is projected over the
lunate with the distal segment volar. A line drawn through the center of the
lunate and scaphoid makes up the scapholunate angle, which should be
between 30 and 60 degrees. Make sure to also closely examine the
radiographs for perilunate or lunate dislocations as well as distal radius,
radial styloid, or scaphoid fractures since they are closely associated with
SLD.

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Figure 281.1 AP radiograph of scapholunate dislocation. (From
Bucholz RW, Heckman JD, eds. Rockwood and Green’s Fractures in
Adults. 5th ed. Philadelphia, PA: Wolters Kluwer, 2002.)

Patients with scapholunate dislocation should be placed in a thumb spica
splint with the wrist in a neutral position or 10 to 15 degrees of dorsiflexion.
Urgent referral to an orthopedist or hand surgeon for surgical repair is
required as these injuries are typically difficult to repair with unpredictable
results. The most common modalities for repair are closed reduction with
percutaneous pinning or open reduction and internal ligamentous repair.
Prompt repair during the acute phase of the injury carries the highest
potential for satisfactory outcomes. We must catch this diagnosis early to
prevent associated sequelae including severe and often debilitating

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degenerative arthritis.

KEY POINTS

Scapholunate dislocation or dissociation (SLD) is the most common
ligamentous injury of the wrist.
Key x-ray findings include a widening of the scapholunate joint space
and the cortical ring sign.
The lateral x-ray is important to check for associated lunate and
perilunate dislocation.

SUGGESTED READINGS

Geissler WB, Freeland AE, Savoie FH, et al. Intracarpal soft-tissue lesions
associated with an intra-articular fracture of the distal end of the radius. J Bone
Joint Surg Am. 1996;78:357–365.

Linscheid RL, Dobyns JH, Beabout JW, et al. Traumatic instability of the wrist:
Diagnosis, classification, and pathomechanics. J Bone Joint Surg Am.
1972;54:1612–1632.

Watson HK, Ashmead D IV, Makhlouf MV. Examination of the scaphoid. J Hand
Surg [Am]. 1988;13:657–660.

Wolfe SW. Chapter 15. Carpal instability. In: Green’s Operative Hand Surgery.
6th ed. London, UK: Churchill-Livingstone, 2011:481–488.

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282

KNOW THE DIFFERENCE BETWEEN
JONES AND PSEUDO-JONES
FRACTURES

BRIAN R. SHARP, MD, FACEP

The proximal fifth metatarsal is the most common site of midfoot fractures
and accounts for 45% to 70% of all metatarsal fractures. The best known is
perhaps the Jones fracture, which was first described in 1902 by Sir Robert
Jones after he injured his foot dancing. However, this fracture is actually far
less common than the pseudo-Jones or fifth metatarsal avulsion fracture.

The fifth metatarsal is composed of three anatomic zones, each with a
corresponding fracture. Significant differences in prognosis and treatment
can depend on mere millimeters, making it very important to be able to
differentiate the three zones and corresponding fracture types (see Figure
282.1).

Figure 282.1 Fifth metatarsal fractures. (Modified from Lawrence SJ,
Botte MJ. Jones’ fractures and related fractures of the proximal fifth

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metatarsal. Foot Ankle. 1993;14(6), Figure 3, page 360, with
permission.)

ZONE 1 TUBEROSITY AVULSION FRACTURES:
PSEUDO-JONES/DANCER’S FRACTURE

Tuberosity avulsion fractures of the fifth metatarsal are often referred to as a
pseudo-Jones or dancer’s fractures. They represent 90% of fractures at the
base of the fifth metatarsal. Although typically visible on standard
anteroposterior (AP), lateral, and oblique foot radiographs, ankle films are
often needed to visualize the fracture—up to 23% are missed with foot
radiographs alone. The fracture itself can have a transverse or oblique
appearance and always occurs proximal to the intermetatarsal joint between
the fourth and fifth metatarsals. Although an avulsion fracture can involve
the metatarsocuboid articulation, it should never involve the intermetatarsal
joint between the fourth and fifth metatarsals.

The typical mechanism of an avulsion tuberosity fracture is forced
inversion of the foot and ankle while in plantar flexion (e.g., a basketball
player landing awkwardly after a jump or runner inverting the ankle on an
uneven surface). Tension generated by the peroneus brevis tendon and/or
lateral cord of plantar aponeurosis (fascia) avulses the tuberosity. Patients
often present complaining of a “sprained ankle” due to the mechanism and
relatively mild symptoms.

Treatment is symptomatic and includes at least 3 weeks of a hard-soled
or cast shoe (± compression dressing) with a goal of preventing significant
plantar flexion and weight-bearing as tolerated. A posterior splint with
crutches or a short leg walking cast for 2 to 3 weeks can be used if there is
severe pain. Orthopedic referral is indicated if there is >3 mm of
displacement, a step-off of more than 1 to 2 mm on the articular surface of
the cuboid, or symptomatic nonunion. All of these may ultimately require
operative intervention.

Multiple metaphyseal blood vessels and branches of the nutrient artery
supply the tuberosity of the fifth metatarsal. Prognosis for these fractures is
thus excellent with most patients being asymptomatic at 3 weeks;
radiographic union is typically seen at 8 weeks. Complications are unusual
but include nonunion or prolonged discomfort. These are more common if
there is a step-off on the articular surface and in older patients.

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ZONE 2 METAPHYSIS/DIAPHYSIS—JONES
FRACTURE

The Jones fracture is an acute fracture of the junction of the diaphysis and
metaphysis of the fifth metatarsal—this is where the widened part of the
bone begins to thin out as it becomes the shaft of the bone (typically within
1.5 cm of the metatarsal tuberosity) and extends toward the intermetatarsal
joint (typically between the fourth and fifth metatarsals). Jones fractures are
frequently accompanied by phalanx fractures. There is particular clinical
significance to the location of this fracture because it can disrupt the blood
supply to the distal portion of the proximal fragment, which is a tenuous
“watershed” area.

The mechanism of a Jones fracture is typically a sudden change in
direction with the heel off of the ground. This creates either a vertical or
lateral force on the forefoot. It is often reported in sports: basketball, soccer,
football, and occasionally tennis. A patient will typically present with pain
and tenderness in the lateral foot. Jones fractures are thought to be more
common in people with a high arched foot shape—this results in increased
loading on the lateral foot.

Initial treatment includes ice, elevation, and immobilization in a posterior
short leg splint with strict non–weight-bearing status and orthopedic follow-
up within 3 to 5 days. Definitive treatment is typically a short leg, non–
weight-bearing cast for 6 to 8 weeks.

Prognosis is guarded because of a high incidence of delayed healing and
nonunion due to the aforementioned poor blood supply to this region. Even
with immobilization, up to one-half later require surgery due to nonunion or
refracture. Early surgical intervention with intramedullary screw fixation is
becoming increasingly common with a high reported rate of primary union.

ZONE 3 PROXIMAL DIAPHYSIS—STRESS
FRACTURES

Diaphyseal stress fractures are seen distal to the ligamentous attachments of
the bone (1.5 cm into the diaphysis). These fractures are typically
symptomatic for several days prior to presentation and are not an acute
injury.

The treatment is immobilization and non–weight bearing for 6 to 10
weeks (similar to that for a Jones fractures), but the prognosis for fracture
union is even worse than with Jones fractures. These often require up to 20

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weeks of immobilization—early surgery is thus an option.

KEY POINTS

An avulsion fracture of the fifth metatarsal occurs with an inversion
injury, whereas a Jones fracture is a lateral force while the heel is off
of the ground.
An avulsion fracture of the fifth metatarsal occurs proximal to the
intermetatarsal joint between the fourth and fifth metatarsals.
While an avulsion fracture can be treated with a postoperative shoe,
both Jones fractures and fifth metatarsal stress fractures require
prolonged immobilization and strict non–weight-bearing status.

SUGGESTED READINGS

Den Hartog BD. Fracture of the proximal fifth metatarsal. J Am Acad Orthop Surg.
2009;17: 458–464.

Hatch RL, Alsobrook JA, Clugstron JR. Diagnosis and management of metatarsal
fractures. Am Fam Physician. 2007;76:817–826.

Polzer H, Polzer S, Mutschler W, et al. Acute fractures to the proximal fifth
metatarsal bone: Development of classification and treatment recommendations
based on the current evidence. Injury. 2012;43:1626–1632.

Zwitser EW, Breederveld RS. Fractures of the fifth metatarsal; diagnosis and
treatment. Injury. 2010;41:555–562.

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283

SEARCH FOR OTHER INJURIES IN
PATIENTS WITH SCAPULAR
FRACTURE

JOHN W. MARTEL, MD, PHD, FACEP

Scapula fractures are uncommon, with an annual incidence of 10 to 12 per
100,000 people. They typically are associated with high-energy, blunt force
mechanisms, including motor vehicle collisions and falls from height, and
therefore are commonly associated with other serious injuries. Although they
constitute <1% of all fractures, scapula fractures are associated with a 10% to
15% mortality rate. Of critical importance, over 90% of patients have
concomitant injuries whose diagnoses may be delayed or overlooked entirely
if not carefully considered. In particular, there is risk of coexisting
multisystem thoracic, orthopedic, intracranial, intra-abdominal, and
neurovascular injury. For example, there is a very high reported incidence
(75% to 98%) of associated injuries to the ipsilateral lung, chest wall, and
shoulder girdle.

During physical examination, fully conscious patients commonly
maintain the affected shoulder in a position of adduction with the extremity
itself held close to the chest wall. In the appropriate clinical context, a variety
of shoulder findings, including ipsilateral ecchymosis, hematoma, focal
tenderness, or crepitus, should raise suspicion for scapula fracture as well as
its associated serious injuries. Scapula fractures occur primarily in the body,
followed by the neck, glenoid, and acromion in descending order. Three-
view shoulder radiographs (anteroposterior [AP], transscapular lateral, and
axillary lateral views) aid in rapid diagnosis via evaluation of both the
glenohumeral structures and scapular body. In some cases, scapula fractures
may also be appreciated on chest x-ray, but they can also be easily missed on

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a portable chest film in a critically injured patient. Computed tomography
(CT) more effectively delineates the fracture and is also most useful in ruling
out associated injury in the stable, multiply injured patient.

With regard to injury patterns, the most common are rib fractures and
acute intrathoracic pathology, such as pneumothorax, hemothorax, and lung
contusions. These are seen together with scapula fracture (in some
combination) in up to two-thirds of cases. In addition, skull fracture and
intracranial injuries, including intracranial hemorrhage and cerebral
contusion, occur in up to 40% of patients. Lastly, up to 10% of cases are
associated with injury to regional vasculature, including the brachial,
subclavian, and axillary arteries.

It is also prudent to look for other orthopedic injuries, with special focus
on the axial skeleton, pelvis, and extremities. A 10-year retrospective review
of blunt trauma admissions at two large, urban level 1 trauma centers
reported that patients with scapular fractures tended to have more severe
injury severity scores and underlying thoracic injuries. Another retrospective
review of the National Trauma Database reported that concomitant injuries to
the thorax, upper extremities, and pelvis were associated with greater
frequency in patients with scapula fracture.

Fortunately, isolated scapula fractures are generally not associated with
permanent disability. The vast majority of cases are managed nonoperatively
with application of a sling and early range of motion, with the exception
being unstable fractures that require operative intervention.

KEY POINTS

Given the high-energy mechanisms that typically break the scapula, a
careful trauma evaluation is required in order to avoid missing
potentially life-threatening injuries.
The most common associated injuries are rib fractures, pneumothorax,
hemothorax, and lung contusions.

SUGGESTED READINGS

Baldwin KD, Ohman-Strickland P, Mehta S, et al. Scapula fractures: A marker for
concomitant injury? A retrospective review of data in the national trauma
database. J Trauma. 2008;65:430–435.

Brown CV, Velmahos G, Wang D, et al. Association of scapular fractures and

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blunt thoracic aortic injury: Fact or fiction? Am Surg. 2005;71:54–57.
Cole PA, Freeman G, Dubin JR. Scapula fractures. Curr Rev Musculoskelet Med.

2013;6(1): 79–87.
Veysi VT, Mittal R, Agarwal S, et al. Multiple trauma and scapula fractures: So

what? J Trauma. 2003;55:1145–1147.

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284

DO YOU KNOW HOW TO DO
ABIS?

JOHN C. RAY, MD

The ankle-brachial index (ABI) is a key diagnostic tool in the assessment of
arterial flow in the lower extremities. It is a noninvasive screening tool for
the identification of peripheral arterial disease and arterial injury which is
used in all clinical settings, including outpatient, inpatient, and the
emergency department (ED). The ABI is quickly performed and simple to
interpret, and it can aid in the management of patients who present with any
concern for lower extremity arterial compromise. Although most frequently
utilized in the outpatient setting to quantify the extent of peripheral arterial
disease, several ED applications exist (see Table 284.1).

TABLE 284.1 INDICATIONS FOR USE OF ANKLE BRACHIAL INDEX IN
THE EMERGENCY DEPARTMENT

Simply stated, an ABI is performed by measuring blood pressure in the upper
and lower extremities and comparing their respective values. The necessary
equipment for performing an ABI is found at the bedside in any standard ED
examination room. These include blood pressure cuffs in a variety of sizes, a
manual sphygmomanometer, a portable Doppler ultrasound, and ultrasound

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gel or lubricating jelly. The following steps delineate the proper technique to
measure and calculate ABIs:

Step 1: Place the patient in supine position.
Step 2: Choose the appropriate blood pressure cuff size for the patient’s
upper arm as well as for the patient’s ankle, and apply the pressure cuff
to the appropriate location. Go one inch above the antecubital fossa for
brachial measurements and 2 to 3 inches above the malleoli for ankle
measurements.
Step 3: For brachial measurements, apply an adequate amount of gel to
the patient’s antecubital fossa, and position the Doppler probe at a 45 to
60-degree angle directed toward the patient’s head to obtain the clearest
arterial pulse signal and keep the probe steadily positioned.
Step 4: Inflate the brachial blood pressure cuff to 20 mm Hg above the
point where the arterial pulse signal is no longer appreciated.
Step 5: Slowly deflate the brachial blood pressure cuff, keeping the
Doppler probe in place, until the arterial pulse signal returns. Record
this number as the brachial systolic pressure for the measured arm.
Step 6: Repeat steps 3 to 5 for the contralateral arm and record that
brachial systolic pressure.
Step 7: For ankle measurements, locate both the dorsalis pedis (DP) and
posterior tibial (PT) pulses using the Doppler probe.
Step 8: Position the Doppler probe steady over the DP pulse and inflate
the ankle blood pressure cuff to 20 mm Hg above the mark where the
DP pulse signal is no longer appreciated and deflate the cuff slowly
until the arterial pulse signal returns. Mark this number as the DP
systolic pressure for the measured side. Some patients may have
congenitally absent DP pulses.
Step 9: Repeat step 7 with the Doppler probe over the PT pulse to
measure the PT systolic pressure for the measured side and record that
number.
Step 10: Apply the blood pressure cuff to the opposite ankle, and repeat
steps 6 and 7 for the opposite ankle and record both numbers.
Step 11: Use the equations shown in Table 284.2 to calculate the ABI
for the patient’s right and left lower extremities.
Step 12: Interpret the results as noted in Table 284.3

TABLE 284.2 CALCULATE ABI FOR RIGHT AND LEFT LOWER
EXTREMITIES

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TABLE 284.3 INTERPRETATION OF MEASURED ABI VALUES IN
PERIPHERAL ARTERY DISEASE

Table 284.3 outlines the interpretation of the ABI in peripheral artery
disease. In trauma or other acute processes, the ABI can also be helpful to
determine patients at risk for lower extremity arterial injury. In patients with
lower extremity trauma, for example, ABI values ≤0.9 have a sensitivity of
87% and specificity of 97% for lower extremity arterial injury and thus
warrant further imaging with angiography or operative intervention. Values
≥0.91 suggest a lower likelihood of arterial injury and a strategy of
observation, repeat ABI measurements, and/or nonemergent angiography.

KEY POINTS

ABI is an important noninvasive test to assess arterial disease or
injury in both ED and outpatient settings.
ABI values ≤0.9 in the acutely injured lower extremity warrants
further evaluation with angiography or operative intervention.

SUGGESTED READINGS

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Grenon SM, Gagnon J, Hslang J. Ankle-brachial index for assessment of peripheral
arterial disease. N Engl J Med. 2009;361:e40.

Johansen K, Lynch K, Paun M, et al. Non-invasive vascular tests reliably exclude
occult arterial trauma in injured extremities. J Trauma. 1991;31(4):515–519.

Newton EJ, Arora S. Peripheral vascular injury. In: Marx JA, ed. Marx: Rosen’s
Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia,
PA: Saunders Elsevier, 2009. Vol. 1: Part II—Trauma.

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285

DON’T MISS THE PROXIMAL
FIBULA FRACTURE IN PATIENTS

WITH ANKLE FRACTURE

SHAWN K. KAKU, MD, STUART SWADRON, MD,
FRCPC

One of the most common musculoskeletal injuries evaluated in the
emergency department (ED) is the twisted ankle. Significant research has
been conducted on the evaluation of the injured ankle in the ED, with the
creation of rules to help aid in the differentiation between a sprain and a
fracture via history and physical examination alone. However, not all ankle
injuries are isolated to the distal extremity. Specifically, one rare but
significant injury pattern of the ankle injury can throw the clinician off track
because it also causes a fracture near the knee. It is known as the
Maisonneuve fracture.

The Maisonneuve fracture is a spiral fracture of the proximal third of the
fibula with disruption of the distal tibiofibular syndesmosis and associated
injury. This fracture pattern is caused when an external rotation force is
applied to the fixed foot. The force of the injury runs from the distal tibia, up
through the interosseous membrane and ends at the proximal third of the
fibula. This force creates an injury pattern that first causes an injury in the
deltoid ligament and/or fracture of the medical malleolus. Next, there is a
rupture of the distal tibiofibular syndesmosis with occasional fracture of the
posterior malleolus. Finally, the force causes a rotational and valgus stress on
the proximal fibula causing a proximal fibular fracture. The characteristic
feature of the Maisonneuve fracture is a spiral or oblique fracture at the
fibular neck or immediately proximal to the neck.

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The mechanism of injury of the Maisonneuve fracture is most often
sports related, followed by injuries caused from slipping on ice, walking or
running, and finally by motor vehicle accidents and falls from height.
Patients may complain of only ankle pain and resultant inability to ambulate
and not complain of proximal fibular pain. This may be due to the minimal
weight-bearing demands of the proximal fibula. On examination, there will
be tenderness present over the deltoid ligament (on the medial side) and the
syndesmosis without lateral ligamentous or distal fibular tenderness. While
there will likely not be any obvious deformity or swelling over the proximal
fibula, there is usually tenderness to palpation. Moreover, the patient may
complain of decreased sensation to the dorsum of the foot. This is a result of
an injury to the peroneal nerve as it crosses over the head of the fibula.

The lack of a historical complaint of proximal fibular pain is precisely
why we need to conduct a thorough examination, extending to at least the
proximal fibula (joint above and joint below!) of any patient with a
complaint of an ankle injury. An x-ray of the ankle often demonstrates a
widening of the distal tibiofibular joint as well as a fracture of the medial
malleolus and/or posterior malleolus. However, in some cases, the proximal
fibular fracture can occur with only soft tissue damage at the level of the
ankle (see Figure 285.1). Only films of the tibia-fibula or knee, if ordered,
will demonstrate the proximal fibula fracture. Furthermore, the talus may
spontaneously reduce medially, leaving little to suspect on the basis of ankle
films alone that a high fibular fracture may be present. Thus, without
recognition of the injury pattern and examination of the proximal fibula,
many patients with Maisonneuve fracture patterns are missed. Tibia and
fibular radiographs should not necessary be obtained routinely, but should be
obtained if there is bony tenderness over the proximal fibula in the setting of
an ankle injury or if an ankle fracture is appreciated on x-ray.

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Figure 285.1 A Maisonneuve fracture with a proximal fibula fracture
(A) and lateral displacement of the talus and widening of the
syndesmosis (B). (From Court-Brown C, Heckman JD, McKee M, et
al., eds. Rockwood and Green’s Fractures in Adults. 8th ed.
Philadelphia, PA: Wolters Kluwer, 2014.)

Treatment of a Maisonneuve fracture is most commonly surgical and
depends on the nature of injury to the ankle mortise. Failed diagnosis can
lead to long-term pain and arthritis. With proper diagnosis and management,
nevertheless, the long-term functional outcome is usually good.

KEY POINTS

The Maisonneuve fracture is a spiral fracture of the proximal third of
the fibula with associated disruption of the ankle. It presents most
commonly as a sprained ankle.

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Management is most often surgical, and delays in diagnosis may result
in complications.
Diagnostic delays can occur because of a failure to examine and, if
necessary, image the proximal fibula in ankle injuries.
The absence of an actual ankle fracture in some cases (only soft tissue
injury) may lead the clinician to underestimate the severity of this
injury.

SUGGESTED READINGS

Duchesneau S, Fallat LM. The Maisonneuve fracture. J Foot Ankle Surg.
1995;34(5):422–428.

Kalyani BS, Roberts CS, Giannoudis PV. The Maisonneuve injury: A
comprehensive review. Orthopedics. 2010;33(3):196–197.

Millen JC, Lindberg D. Maisonneuve fracture. J Emerg Med. 2011;41(1):77–78.
Taweel NR, Raikin SM, Karanjia HN, et al. The proximal fibula should be

examined in all patients with ankle injury: A case series of missed maisonneuve
fractures. J Emerg Med. 2013;44(2):e251–e255.

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286

BOXER’S FRACTURE? CHECK FOR
ROTATIONAL DEFORMITY!

JENNIFER MARVIL, MD, MA

Boxer’s fracture is the common name for a fifth metacarpal neck fracture,
although the term is often applied to fractures of both the fourth and fifth
metacarpals. Metacarpal fractures account for ~40% of hand injuries;
fractures of the metacarpal neck are the most common type of metacarpal
fracture with the fifth metacarpal being the most commonly injured,
accounting for ~20% of all hand fractures. The highest incidence of boxer’s
fractures is seen in men ages ~15 to 30 years. Despite the name, boxer’s
fractures are not very common in trained boxers but are seen more frequently
in untrained fighters.

The pattern of a boxer’s fracture occurs due to a direct impact or axial
load to the metacarpal head with the metacarpophalangeal (MCP) joint in
flexion, often as a result of a punch thrown against a solid surface. This
fracture is inherently unstable due to the loss of proximal stabilizing forces to
the metacarpal head, as the collateral ligaments insert proximally on the sides
of the metacarpal head and distally onto the phalanx. The loss of proximal
stabilizing forces and the typical direction of impact onto the dorsum of the
metacarpal head generally lead to volar angulation of the metacarpal head.

Clinically, a boxer’s fracture can be diagnosed by swelling, deformity, or
tenderness over the metacarpal or depression of the fifth MCP joint. The
hand should additionally be examined for skin integrity, as a laceration
sustained as a result of blows to an opponent’s mouth (also known as a “fight
bite”) can lead to serious bacterial infection and functional impairment.
Radiographic characteristics of a boxer’s fracture include a typically oblique
fracture of the metacarpal neck with volar angulation of the distal segment
and metacarpal head (see Figure 286.1).

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Figure 286.1 Boxer’s fracture. Oblique radiograph of the hand shows
a fracture of the fifth metacarpal (arrow) with volar angulation of the

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distal fragment. (From Siegel MJ, Coley B, eds. Core Curriculum:
Pediatric Imaging. Philadelphia, PA: Wolters Kluwer, 2005.)

Metacarpal neck fractures can tolerate a variable degree of angulation
without functional impairment. Angulation is best assessed on the lateral
radiograph of the hand. The acceptable degree of angulation is different for
each digit. While the exact number of allowed angulation at each digit varies
between sources, ~10, 20, 30, and 40 degrees of angulation are allowed as
you move from the second to fifth metacarpal. The acceptable volar
angulation is in addition to the inherent 15 degrees of volar angulation
between the fifth metacarpal neck and head. More volar deformity is allowed
at the fifth metacarpal because the fifth carpometacarpal joint is more mobile
than the other carpometacarpal joints, allowing for more rotational capacity
to facilitate opposition. Similarly, the thumb can also tolerate ~40 degrees of
volar angulation for a fracture of the first metacarpal neck due to the
increased rotational capacity at the first carpometacarpal joint to allow for
opposition.

Yet, while fractures of the fifth metacarpal neck can tolerate a great deal
of angulation, no degree of rotational deformity is acceptable. Rotational
deformity leads to functional impairment due to overlap of digits resulting in
decreased grip strength. Rotational deformity can be assessed by both
clinical and radiographic findings. With fingers flexed at both the MCP and
proximal interphalangeal (PIP) joints, all digits should point to the scaphoid
tuberosity. Additionally, the nail beds of the digits should be in alignment
with the digits in extension. One should suspect a rotational deformity if all
the digits do not align uniformly or if there is overlap of the fourth and fifth
digits with a closed fist. In addition to the clinical exam findings, radiographs
of the hand should be assessed for rotation in addition to angulation. While
volar angulation is best assessed on lateral films, any apparent angulation
observed on an anteroposterior (AP) film represents significant malrotation.
It is important to note, however, that radiographs of the hand are not very
sensitive for detecting malrotation. Therefore, the provider should remain
diligent in assessing for rotational deformity clinically. Fractures with
malrotation require orthopedic referral for operative fixation to prevent
functional impairment.

KEY POINTS

Boxer’s fracture refers to the fracture of the fifth metacarpal neck as a

1219

result of closed fist impact to a hard surface. This is the most common
metacarpal fracture of the hand.
While metacarpal fractures can tolerate variable degrees of volar
angulation (depending on the digit involved), no degree of rotational
deformity is acceptable. Clinicians should diligently assess all boxer’s
fractures for presence of rotational deformity clinically as
radiographic findings may not be sensitive enough to detect
malrotation of the distal fragment.
Rotational deformity can be assessed by looking for overlap of the
fourth and fifth digits while forming a closed fist, or by evaluating the
alignment of the nail beds of all digits in extension. All fractures with
rotational deformity will require orthopedic referral for operative
fixation in order to prevent functional impairment due to decreased
grip strength.

SUGGESTED READINGS

Ali A, Hamman J, Mass DP. The biomechanical effects of angulated boxer’s
fractures. J Hand Surg [Am]. 1999;24A(4):835–844.

Leung YL, et al. Radiographic assessment of small finger metacarpal neck
fractures. J Hand Surg [Am]. 2002;27A(3):443–448.

Pace GI, Gendelberg D, Taylor KF. The effect of closed reduction of small finger
metacarpal neck fractures on the ultimate angular deformity. J Hand Surg
[Am]. 2015;40:1582–1585.

Sletten IN, et al. Assessment of volar angulation and shortening in 5th metacarpal
neck fractures: An inter-and intra-observer validity and reliability study. J
Hand Surg [Am]. 2012;38E(6):658–666.

Soong M, Got C, Katarincic J. Ring and little finger metacarpal fractures:
Mechanisms, locations, and radiographic parameters. J Hand Surg [Am].
2010;35A:1256–1259.

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287

THINK OF ACHILLES TENDON
RUPTURE IN PATIENTS WITH

SPRAINED ANKLE

JENNIFER FARAH, M

Sprained ankles run the gamut, some with impressive physical exam findings
(e.g., diffuse edema, extensive ecchymosis) and others with only mild
limitations in range of motion. Regardless, the workup may include an x-ray,
which if negative for a fracture is typically followed by the application of an
elastic bandage and recommendations for RICE (rest, ice, compression, and
elevation) therapy. However, a very concerning diagnosis may be slipping
away—one that is often not considered in what appears to be a benign ankle
sprain—an Achilles tendon rupture.

The Achilles tendon is the largest tendon in the body. Unfortunately, it is
also one of the most poorly vascularized, and thus, it is vulnerable to injury.
It connects the gastrocnemius and soleus muscles to the calcaneus. With
every step, it undergoes repetitive inversion and eversion, which can lead to
an incredible amount of microtrauma and inflammation over time. Running,
jumping, and other sports-related movements can exacerbate an already
weakened tendon, causing further damage. Tendonitis and bursitis are
common conditions, but even more concerning is a full or partial rupture of
the Achilles tendon.

Given the subtlety of presentation, nearly 25% of Achilles tendon
injuries are initially missed. Most patients with these injuries are men, 30 to
50 years old, and seasoned athletes are just as vulnerable as newcomers. The
patient may report that he made a very sudden movement, heard a “pop,” and
was unable to continue with his current activity. For example, a basketball

1221

player may describe having his feet firmly planted while he pivoted to catch
a pass. Another common description is the sensation of being “kicked in the
back of the ankle.”

On examination, the provider may palpate a noticeable defect or “knot”
along the length of the tendon. One may also appreciate a loss of plantar
flexion or an inability to perform a toe raise. However, not all cases are this
obvious, and more provocative testing may be necessary. In the Thompson
test, the patient is placed supine with the affected limb flexed 90 degrees at
the knee. The physician then squeezes the calf and observes if there is plantar
flexion of the foot. If it is absent, this is considered an abnormal test and an
Achilles tendon injury should be suspected. If there is limited plantar flexion,
the physician can further investigate by placing a sphygmomanometer on the
calf. With the patient in the same supine position, and the foot plantar flexed,
the cuff should be inflated to 100 mm Hg. The physician then passively
dorsiflexes the foot at the sole and observes for a rise in the pressure reading.
With an intact tendon, the pressure should rise to 140 mm Hg. This value can
vary from person to person; thus, to ensure the most accuracy, this test
should also be performed on the unaffected limb to note the patient’s
baseline.

It is important to remember that patients with Achilles tendon injuries
may have retained plantar flexion due to the action of other surrounding
muscles, such as the flexor hallucis longus and tibialis posterior. Therefore,
imaging may be needed to make a definitive diagnosis. Magnetic resonance
(MR) and ultrasound (US) are both very helpful. Given the high cost and
limited access to an emergent MR, US is favored in the emergency
department. Findings include a loss in tendon continuity or variation in
echogenic texture of the tendon that could represent a partial tear. However,
these findings are operator dependent and are not as sensitive as MR.

Treatment of an Achilles tendon rupture involves prolonged
immobilization or surgical repair plus immobilization. The decision of which
course to pursue is made in conjunction with an orthopedic surgeon and takes
into consideration the patient’s level of activity. If immobilization is
performed in the ED, the ankle should be immobilized in plantar flexion
(splint or cast in equinus) and the patient should anticipate that the
immobilization will remain for possibly 8 to 12 weeks, with the first 3 to 4
weeks as non–weight bearing. Expectations should be managed; the patient
should expect a slow recovery that may not lead to full return of function.

KEY POINTS

1222

Achilles tendon rupture should be on the differential diagnosis of any
patient who presents with ankle pain.
Patients with Achilles tendon injury show limited or lack of foot
plantar flexion upon the provider squeezing their calf (abnormal
Thompson test).
A bedside US of the tendon can be a useful adjunct in making the
diagnosis for an Achilles tendon rupture.
Once the diagnosis is made, the ankle should be immobilized in
plantar flexion (equinus), and the patient should be referred to an
orthopedic surgeon for follow-up.

SUGGESTED READINGS

Copeland SA. Rupture of the Achilles tendon: A new clinical test. Ann R Coll Surg
Engl. 1990;72(4):270–271.

Gulati V, Jaggard M, Al-Nammari SS, et al. Management of Achilles tendon
injury: A current concepts systematic review. World J Orthop.
2015;6(4):380–386.

Kayser R, Mahlfeld K, Heyde CE. Partial rupture of the proximal Achilles tendon:
A differential diagnostic problem in ultrasound imaging. Br J Sports Med.
2005;39(11):838–842; discussion 838–842.

Mazzone MF, McCue T. Common conditions of the Achilles tendon. Am Fam
Physician. 2002;65(9):1805–1810.

Reiman M, Burgi C, Strube E, et al. The utility of clinical measures for the
diagnosis of Achilles tendon injuries: A systematic review with meta-analysis.
J Athl Train. 2014;49(6):820–829.

1223

288

REDUCE HIP DISLOCATIONS IN A
TIMELY MANNER

ERIK A. BERG, MD

Hip dislocation is an orthopedic emergency that requires prompt diagnosis,
evaluation and treatment. This injury primarily occurs after a high-energy
traumatic mechanism such as head-on motor vehicle collision (MVC), auto-
versus-pedestrian accident, major fall, and contact sports injury.
Consequently, hip dislocation is frequently accompanied by life-and limb-
threatening injuries. Nevertheless, providers should know that the outcome
of a hip dislocation is related to the time to reduction. The earlier the
reduction—which should be within 6 hours of the injury—the better the
results.

The hip joint is formed by the articulation of the proximal head of the
femur (the “ball”) into the acetabulum (the “socket”). Reinforced by labral
cartilage, a joint capsule, and strong muscular and ligamentous attachments,
the hip joint is generally very stable and requires significant force to
dislodge. The medial and lateral circumflex femoral arteries provide the
majority of blood supply to the femoral head. These are terminal arteries
with poor collaterals. When disrupted, they render the femoral head
susceptible to avascular necrosis (AVN).

Hip dislocations are classified as anterior, posterior, or central, based the
position of the femoral head relative to the acetabulum. Posterior dislocations
account for about 80% of all hip dislocations and most commonly occur in
high-speed MVC. Patients present with a shortened leg held in adduction
with the hip flexed and internally rotated. Anterior hip dislocations (10% to
15%) occur with forceful hip abduction, extension, and external rotation and
may present as a lengthened leg with an abducted, flexed, and externally
rotated hip. Central dislocations are very rare and result from direct impact

1224

on the lateral thigh, forcing the femoral head through a comminuted
acetabulum (a fracture dislocation of the hip).

A plain anteroposterior (AP) film of the pelvis is typically the only
imaging necessary to confirm the diagnosis. The AP pelvis x-ray should be
examined for any interruption of Shenton line (normally, the smooth,
continuous contour of the inferior border of the superior pubic ramus and the
inferomedial border of the neck of femur), which should raise suspicion for
hip dislocation or femoral neck fracture. Shenton line is illustrated in Figure
288.1. Additional imaging should be performed for two reasons: (1) if the
patient requires a CT scan for other injuries and there is additional time to
quickly obtain cuts through the acetabulum and femoral metaphysis or (2)
the AP view of the femoral neck is inadequate to rule out fracture. In the
second case, lateral or oblique (Judet) plain films may be useful adjuncts.

Figure 288.1 Shenton line (dashed line). (From Pope TL Jr, Harris JH
Jr. Harris & Harris’ The Radiology of Emergency Medicine. 5th ed.
Philadelphia, PA: Lippincott Williams & Wilkins, 2012.)

1225

The goal in managing hip dislocation is reduction in <6 hours. The primary
contraindication to a closed reduction is a femoral neck fracture. Other
fractures of the acetabulum and femur are not contraindications, though they
may render the reduction more difficult. Although reduction is within the
scope of practice of emergency physicians, appropriate procedural sedation
and analgesia should be employed and preparations for splinting should be
made prior to the reduction. Avoid multiple attempts at reduction in the
emergency department, as there is an increased associated risk of damage to
the articular surface and AVN with each attempt. If the fracture is
irreducible, the patient will require a trip to the operating room for either a
closed reduction under general anesthesia or an open reduction.

Complications from hip dislocations include traumatic arthritis, sciatic
nerve dysfunction, and most importantly, AVN of the femoral head. AVN is
perhaps the most disabling sequela of hip dislocations. In order to minimize
the risk for the development of AVN, reduce the hip within 6 hours of injury!

KEY POINTS

Consider hip dislocation in high-energy traumatic mechanisms such as
MVCs or falls from height.
Any disruption of Shenton line should raise suspicion for a fracture or
dislocation.
Reduction should be performed as soon as possible and in <6 hours to
avoid the complication of AVN.

SUGGESTED READINGS

Brooks RA, Ribbans WJ. Diagnosis and imaging studies of traumatic hip
dislocations in the adult. Clin Orthop Relat Res. 2000;377:15–23.

Clegg TE, Roberts CS, Greene JW, et al. Hip dislocations—Epidemiology,
treatment, and outcomes. Injury. 2010;41:329–334.

Hak DJ, Goulet JA. Severity of injuries associated with traumatic hip dislocation as
a result of motor vehicle collisions. J Trauma. 1999;47:60–63.

Newton E, Love J. Emergency department management of selected orthopedic
injuries. Emerg Med Clin North Am. 2007;25:763–793.

Sahin V, et al. Traumatic dislocation and fracture dislocation of the hip: A long-
term follow-up study. J Trauma. 2003;54:520.

Yang EC, Cornwall R. Initial treatment of traumatic hip dislocation in the adult.
Clin Orthop Relat Res. 2000;377:24.

1226

289

CHECK FOR SNUFFBOX
TENDERNESS AND DON’T MISS A

SCAPHOID FRACTURE

BENJAMIN D. MUSSER, MD

Wrist pain is a very commonly encountered chief complaint in the
emergency department (ED), and emergency providers must be aware of the
high rate of scaphoid fractures among patients with acute wrist pain. The
scaphoid bone is the most commonly broken wrist bone, and fracture is often
the result of axial loading of the wrist via a fall onto an outstretched hand.

The scaphoid is a crescent-shaped bone in the wrist and the largest of the
proximal carpal bones. Its anatomy can be remembered by dividing it into
thirds: the proximal pole, the middle third (waist), and the distal pole. An
understanding of the unique blood supply to the scaphoid helps us to best
treat these injuries. The scaphoid receives its vascular supply from the
palmar carpal branch of the radial artery. This branch enters the scaphoid at
the distal end and then travels retrograde toward the proximal pole. The waist
and proximal pole of the scaphoid are therefore dependent on an intact distal
blood supply, which will frequently become compromised after fracture.

When a suspicious history for scaphoid fracture exists, clinical exam of
the wrist will often help solidify the diagnosis. Examination will classically
reveal tenderness and/or swelling over the anatomical snuffbox (best tested
with the wrist in slight volar flexion and ulnar deviation). Tenderness will
also be elicited with palpation over the scaphoid tubercle on the volar aspect
of the hand and with axial loading of the thumb metacarpal. All three of
these quick bedside maneuvers correlate with the presence of a scaphoid
fracture.

1227

When ordering x-rays to look for a scaphoid fracture, the series will need
to have a dedicated scaphoid view. Obtaining this view involves placing the
patient’s hand in full pronation with as much ulnar deviation of the wrist as
tolerated. A clear fracture line is obviously indicative of fracture, but more
subtle findings such as obliteration or displacement of the scaphoid fat pad
may indicate the presence of a fracture as well. A study by Waeckerle et al.
showed that plain radiographs performed after an acute injury have a false-
negative rate of up to 20%. Therefore, if clinical suspicion for a scaphoid
fracture is high despite negative radiographs, empiric immobilization is
recommended. Repeat wrist radiographs can be obtained in 1 week in such
cases. This will allow more time for any fracture to present itself, while
keeping the patient immobilized in the interim. If faster diagnosis is
necessary, as in the case of athletes who would otherwise return to play,
Carpenter et al. showed that magnetic resonance (MR) and computed
tomography (CT) have excellent sensitivity and specificity for identifying
scaphoid fracture even in the acute setting.

Splinting or casting after a scaphoid fracture focuses on immobilization
of the scaphoid and usually requires placement of a thumb spica cast or
splint. Duration of immobilization varies, but longer immobilization is
required for more proximal fractures because of the higher risk of avascular
necrosis and nonunion. This increased risk can be explained by the pattern of
blood supply described above. The compromised blood supply to the
proximal pole in a proximal or neck fracture can impede healing and greatly
increase the likelihood of avascular necrosis.

If there is significant concern for complication after scaphoid fracture,
orthopedic referral from the ED is warranted. Several criteria for urgent
orthopedic referral include

Fractures of the proximal pole
Greater than 1 mm displacement of fracture segments
Delayed presentation. Langhoff et al. showed that patients with delayed
presentation of 4 weeks after their initial scaphoid injury had as high as
40% rate of nonunion.

In patients with uncomplicated scaphoid fractures without evidence of
nonunion, there is no evidence showing a long-term benefit of surgical
intervention compared to immobilization. However, there is a slight decrease
in time to return to work with surgical intervention as shown in a study by
Bond et al. (8 weeks vs. 15 weeks in a small study involving 25 patients).

1228

KEY POINTS

Scaphoid fracture is the most common fracture involving the carpal
bones of the wrist. The most common mechanism of injury is a fall
onto an outstretched hand.
Snuffbox tenderness, tenderness upon palpation of scaphoid tubercle,
and pain with axial loading of the thumb metacarpal are physical
exam findings that should increase suspicion for scaphoid fracture.
It is important to immobilize the wrist and thumb with a thumb spica
splint if clinical suspicion for scaphoid fracture exists, even despite
negative radiographs.

SUGGESTED READINGS

Bond CD, et al. Percutaneous screw fixation or cast immobilization for
nondisplaced scaphoid fractures. J Bone Joint Surg Am. 2001;83-
A(4):483–488.

Carpenter CR, et al. Adult scaphoid fracture. Acad Emerg Med. 2014;21:102.
Langhoff O, Andersen JL. Consequences of late immobilization of scaphoid

fractures. J Hand Surg Br. 1988;13(1):77–79.
Waeckerle JF. A prospective study identifying the sensitivity of radiographic

findings and the efficacy of clinical findings in carpal navicular fractures. Ann
Emerg Med. 1987;16:733.

1229

290

CALCANEAL FRACTURE? DON’T
MISS A SPINAL INJURY!

SARA KHAGHANI, MD, MPH

Calcaneus fractures are a source of debilitating disease and are important to
quickly identify. The incidence of calcaneal fracture is 11.5 per 100,000,
with a male to female predominance of 2.4:1. These fractures have high rates
of acute and long-term complications. They are often the result of high-
impact trauma, most often occurring after an axial load injury on the foot
after a fall (or jump!) from 6 feet or more. In one study, 72% of calcaneus
fractures occurred after a fall.

Plain films are the initial study of choice for confirming the presence of a
calcaneal fracture. Lateral and axial (Harris) views of calcaneus as well as an
anteroposterior (AP) view of the foot are indicated. Additional views or
computed tomography (CT) may be required to further define the extent of
the fracture. CT is often used in cases where the fracture is intra-articular.
Intra-articular calcaneus fractures have a poorer prognosis because they
extend into the weight-bearing subtalar joint. An orthopedic surgeon should
be consulted for these injuries for proper management; urgent referral is
usually sufficient.

Open fractures, any neurovascular injury, fractures with dislocation and
acute compartment syndrome are potential complications that require
emergent orthopedic surgical consultation. It is important to be aware of skin
necrosis, which can commonly occur when there is posterior displacement of
the calcaneus.

Initial management of calcaneus fracture includes elevation of the limb
about the level of the heart, as well as icing of the injury. A bulky
compression dressing (also referred to as a bulky Jones splint) should be

1230

applied. Of course, analgesia is indicated. Frequent skin exams are required
to assess for skin necrosis and compartment syndrome. Surgical repair may
be indicated for displaced and comminuted fracture patterns involving the
articular spaces of the foot.

It has been shown that up to 50% of patients with calcaneal fracture have
other associated injuries. The most commonly seen concomitant injuries are
to the lower limbs (13.2%) and thoracolumbar spine (6.3%). In addition,
about 5% of patients have bilateral calcaneal fractures. It is therefore
important to do a careful head-to-toe examination of the axial and
appendicular skeleton and a neurologic exam that includes motor function,
sensation, reflexes, and position sense. In patients with a high-force
mechanism or signs of injury on examination, imaging of the axial skeleton
(e.g., x-ray or CT of the thoracolumbar spine) is appropriate. CT has a higher
sensitivity for detecting spinal fractures.

KEY POINTS

Calcaneus fracture results from high-impact trauma such as a fall from
significant height, and is associated with other injuries.
Carefully examine the other calcaneus, thoracolumbar spine, and
lower limbs.
Adequate initial radiographic views to assess for calcaneal fracture
include lateral and axial (Harris) views of the calcaneus, as well as an
AP view of the foot.
Clinicians should be aware of possible compartment syndrome and
skin necrosis of the foot as a result of calcaneus fracture. Emergent
orthopedic consultation is indicated if either appears imminent.

SUGGESTED READINGS

Antevil JL, Sise MJ, Sack DI, et al. Spinal computed tomography for the initial
evaluation of spine trauma: A new standard of care? J Trauma. 2006;61(2):382.

Mitchell MJ, McKinley JC, Robinson CM. The epidemiology of calcaneal
fractures. Foot (Edinb). 2009;19(4):197–200.

Walters JL, Gangopadhyay P, Malay DS. Association of calcaneal and spinal
fractures. J Foot Ankle Surg. 2014;53(3):279–281.

1231

291

BEWARE OF BENIGN-APPEARING
HIGH-PRESSURE INJECTION
INJURIES

JENNIFER FARAH, MD

“Looks can be deceiving” has never been truer than when identifying high-
pressure injection injuries. Presentation may be limited to a small puncture
wound or a vague neurologic deficit. Thus, we must be diligent in
investigating the details of the injury. Common causes of high-pressure
injection injury are paint guns, grease guns, and other occupational
instruments. Men are more likely to present with such injuries, with an
average age in the 30s. Often, the patient was exploring a clogged nozzle
when the injury occurred. This is why the index finger of the nondominant
hand is the most common digit injured. Even the most experienced skilled
workers are not immune to these mishaps.

Delay in presentation is common, as the injected material may not
initially cause discomfort. It may take many hours before the patient feels
compelled to visit the emergency department. As the agent disturbs the
surrounding tissues, inflammatory processes take effect, and this leads to
further swelling and pain. While nearby blood vessels and nerves become
compressed, the finger will appear more edematous, tense, and pale, and
often the patient will report pain and paresthesia. Limitations in range of
motion and compromised perfusion may be appreciated on examination, with
only a small punctate lesion noted grossly. The foreign material will then use
neurovascular bundles and tendon sheaths as a highway to travel more
proximally. One case report found that an auto mechanic suffered
pneumomediastinum as a consequence of compressed air injected into his
hand. This serves as a reminder, yet again, that although these patients may

1232

have wounds that are unimpressive at first glance, the level of underlying
damage can be devastating.

The material injected should, of course, be determined. Systemic reviews
have noted that organic solvents, such as paint, paint thinner, fuels, and oil
tend to be more caustic and therefore more likely to lead to amputation. On
the other hand, the inflammatory response to air or water is less robust.

Injections should be further explored initially with x-ray. The clinician
may note a radiopaque substance, for example with paint, revealing the
extent of injury. Also, there may be an increased lucency indicating that
water or air has disrupted the tissue. Administration of broad-spectrum
antibiotics and tetanus prophylaxis is advised. The role for steroids is still in
question; their effect on dampening the inflammatory process may be
beneficial but they have not been shown to reduce the incidence of
amputation. Ultimately, no medical therapy should delay the ultimate
intervention, which is surgical debridement.

Time to surgical debridement is of the utmost importance, as amputation
rates can be as high as 50%. Studies have shown that the risk of amputation
is less if the patient undergoes debridement within 6 hours of injury. Surgical
exploration is needed to not only eradicate the offending chemical and
irrigate the necrotic tissue but also decompress surrounding nerves and
vessels. There are minimal published data regarding the overall functional
outcome of these patients, but any efforts to reduce the chance of amputation
should be welcomed; patients who often suffer from these injuries usually
are dependent on maintaining proper dexterity more than most.

KEY POINTS

High-pressure injection injuries often have a benign appearance on
examination, yet this mechanism of injury indicates significant
underlying tissue injury.
Plain radiographs of the affected extremity may help reveal the true
extent of the underlying injury.
Though broad-spectrum antibiotics and tetanus prophylaxis are
advised in these cases, time to surgical exploration and debridement is
the most important factor in preventing a devastating outcome and
minimizing the chance of amputation.

1233

SUGGESTED READINGS

Amsdell SL, Hammert WC. High-pressure injection injuries in the hand: Current
treatment concepts. Plast Reconstr Surg. 2013;132(4):586e–591e.

Hogan CJ, Ruland RT. High-pressure injection injuries to the upper extremity: A
review of the literature. J Orthop Trauma. 2006;20(7):503–511.

Kennedy J, Harrington P. Pneumomediastinum following high pressure air
injection to the hand. Ir Med J. 2010;103(4):118–119.

Rosenwasser MP, Wei DH. High-pressure injection injuries to the hand. J Am Acad
Orthop Surg. 2014;22(1):38–45.

1234

292

LISFRANC INJURY: DANGER IN THE
MIDFOOT

LEE PLANTMASON, MD, MPH

Lisfranc injury is an injury to the tarsometatarsal (TMT) joint complex. It
constitutes roughly 0.2% of all fractures, and is considered one of the causes
of significant disability from injuries to mid-and forefoot. It can occur from
both low-energy mechanisms, such as falls from standing and athletic
injuries, and high-energy mechanisms, such as falls from height, crush
injuries of the foot, and motor vehicle collisions. While history and physical
examination with careful attention to plain radiographs are important, plain
radiographs are not always diagnostic due to overlapping bones, especially
on the lateral view. Up to 20% of these injuries may not be accurately
diagnosed on initial plain radiographs, making them a high-risk injury for
emergency physicians to miss.

A brief review of foot anatomy helps in understanding Lisfranc injuries.
The forefoot is composed of five metatarsal bones and their associated
phalanges. The midfoot also consists of five bones: three cuneiforms (medial,
middle, and lateral), the cuboid, and the navicular. The Lisfranc or TMT joint
consists of the articulations between the metatarsals and the three cuneiforms
and cuboid, all very critical to the stability of the foot. The Lisfranc joint is
composed of three longitudinal components, the medial column (medial
cuneiform and first metatarsal), middle column (middle and lateral
cuneiforms with the second and third metatarsals) and the lateral column (the
cuboid and the fourth and fifth metatarsals). The Lisfranc ligament runs from
the plantar medial cuneiform to the base of the second metatarsal, while the
second through fifth metatarsals are interconnected through a series of
intermetatarsal ligaments, thus connecting the medial column to the lateral
four metatarsals and serving as the primary soft tissue support of the TMT

1235

articulation.
Lisfranc injury results from both direct and indirect trauma; most

commonly direct trauma includes crush injures associated with significant
soft tissue injury, vascular insufficiency, and compartment syndrome of the
foot. Most common indirect injury patterns are due to forced external
rotation, axial loading of a foot in plantar flexion, or twisting of an axially
loaded foot in fixed equinus position where forced abduction of the forefoot
causes dislocation of second metatarsal and lateral metatarsal displacement.
For example, when first described by French war surgeon Jacques Lisfranc
de St. Martin, a soldier who fell off his horse with his foot still in the stirrups
might have sustained this type of injury.

In general, patients with Lisfranc injuries tend to present with midfoot
tenderness, edema, and an inability to bear weight. Forefoot and midfoot
edema with plantar ecchymosis are considered pathognomonic for Lisfranc
injury. Other physical exam findings suggestive of TMT joint injury include
the “piano key test,” where one can induce pain or subluxation by
dorsiflexion and plantar flexion (or abduction and adduction) of the first and
second metatarsals.

Anteroposterior (AP), oblique, and lateral x-ray views are utilized for
initial assessment of Lisfranc injury. The AP is used to assess the alignment
of the first and second TMT joints by determining if the medial border of the
second metatarsal lines up with that of the middle cuneiform. The oblique is
used to assess the other TMT joints, by determining if the medial border of
the fourth metatarsal lines up with the cuboid. Lateral radiograph may show
dorsal dislocation or subluxation between the first and second metatarsals.
Additionally, avulsion fractures of the second metatarsal or medial
cuneiform, also known as the “fleck sign,” or >2 mm of diastasis between the
first and second metatarsals suggest TMT joint injury (see Figure 292.1).

1236

Figure 292.1 AP x-ray of patient with a Lisfranc injury. The medial
border of the second metatarsal does not line up with that of the
middle. Note the “fleck sign,” representative of an avulsion of the
Lisfranc ligament from the base of the second metatarsal. (From

1237

Altchek DW. Foot and Ankle Sports Medicine. Philadelphia, PA:
Wolters Kluwer, 2012.)

If a Lisfranc injury is clinically suspected despite normal imaging, either
weight-bearing or stress views of the foot should be obtained including
oblique, lateral, and AP views. Any displacement > 2 mm between the first
and second metatarsals is diagnostic of ligamentous Lisfanc injury.
Comparison x-ray views of the unaffected foot can also aid in the diagnosis.
Given the pain and discomfort of obtaining these views, the patient should
receive analgesia prior to obtaining films and receive clarification on why
additional images are needed.

Management of Lisfranc injuries depends on the degree of displacement.
Minimally displaced (<1 mm between the first and second metatarsals)
Lisfranc injury is generally managed conservatively with a non–weight-
bearing splint, rest, ice, and elevation with outpatient orthopedic evaluation
at 2 weeks. In general, these patients will remain in a controlled ankle
movement (CAM) boot for 6 to 10 months before starting physical therapy.
On the other hand, displaced Lisfranc injuries (>2 mm of displacement) are
unstable and require orthopedic consultation from the ED with specific
attention placed on monitoring for compartment syndrome. These injuries
will usually require transarticular fixation or arthrodesis depending on the
degree of injury and will not bear weight for 8 to 15 weeks.

KEY POINTS

Lisfranc injury occurs from injury to the TMT joint, and if not
diagnosed and properly managed can lead to significant disability to
the patient. Midfoot tenderness and edema, plantar ecchymosis, and
inability to bear weight on examination should raise suspicion for
Lisfranc injury.
When a Lisfranc injury is suspected, foot radiographs can reveal
malalignment of the TMT joints and/or the fleck sign. Weight-bearing
or stress views, or comparison views of the unaffected foot can aid in
diagnosis when initial radiographs are nondiagnostic and clinical
suspicion for the injury remains high.
Patients with Lisfranc injury should be splinted with instructions to
remain non–weight bearing. Minimally displaced injuries can be
urgently referred to orthopedics as outpatient, while displaced injuries
with significant soft tissue edema should be monitored for

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compartment syndrome and be evaluated by an orthopedic surgeon in
the ED.

SUGGESTED READINGS

Aronow MS. Treatment of the missed Lisfranc injury. Foot Ankle Clin. 2006;11(1):
127–142.

Mantas JP, Burks RT. Lisfranc injuries in the athlete. Clin Sports Med.
1994;13(4):719–730.

Peicha G, Labovitz J, Seibert FJ, et al. The anatomy of the joint as a risk factor for
Lisfranc dislocation and fracture-dislocation. An anatomical and radiological
case control study. J Bone Joint Surg Br. 2002;84(7):981–985.

Schenck RC Jr, Heckman JD. Fractures and dislocations of the forefoot: Operative
and nonoperative treatment. J Am Acad Orthop Surg. 1995;3(2):70–78.

Trevino SG, Kodros S. Controversies in tarsometatarsal injuries. Orthop Clin
North Am. 1995;26(2):229–238.

Watson TS, Shurnas PS, Denker J. Treatment of Lisfranc joint injury: Current
concepts. J Am Acad Orthop Surg. 2010;18(12):718–728.

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293

THE DORSAL CHIP: IS IT A
TRIQUETRAL FRACTURE?

CAROLINE BRANDON, MD

Carpal bone fractures are very common, with scaphoid fracture constituting
the majority of injuries. The second most common type of carpal fracture is
the triquetral fracture, constituting from 15% to 19% of all carpal fractures.
Triquetral fractures occur by mechanisms similar to scaphoid fractures. Yet
they can be very subtle in presentation and on x-ray, so it is important to be
on the lookout for these injuries.

There are three major types of triquetrum fracture: dorsal cortical, body,
and volar. Dorsal cortical fractures occur with a fall onto a dorsiflexed and
ulnarly deviated hand. Patients present with midwrist tenderness, edema, and
pain with range of motion. Anteroposterior (AP) and oblique wrist x-rays
generally show no acute abnormality. Yet, the lateral x-ray of the wrist
generally shows a dorsal fleck of bone. (see Figure 293.1) As a result, this
pattern of fracture is also commonly referred to as a dorsal chip fracture.
This fracture rarely requires surgery and is usually splinted with a volar
splint and then subsequently casted. Return to full function is expected in 6
to 8 weeks.

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Figure 293.1 Triquetral fracture. Lateral radiograph shows displaced
avulsion fragment (arrow) with overlying soft tissue swelling. (From
Chew FS. Skeletal Radiology. 3rd ed. Philadelphia, PA: Wolters
Kluwer, 2010.)

Triquetral body fractures constitute 3% of triquetral fractures, and they can
be further divided into 3 subcategories. Sagittal body fractures are associated
with crush injuries and axial dislocations. Medial tuberosity fractures occur
from a direct blow to the triquetrum. Transverse body fractures are
associated with a high-speed trauma, perilunate injuries, or other
comminuted fractures. As these injuries are the result of high-energy
mechanisms, the physical examination of such wrists typically reveals
significant swelling and limitation of range of motion. Plain radiographs
usually demonstrate these various fracture patterns, as well as ligamentous

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instability. Nonetheless, if the x-rays are negative and the clinical suspicion
(based on mechanism of injury and degree of soft tissue injury) remains high,
computed tomography (CT) of the wrist is appropriate. These injuries often
require surgical repair with open reduction; orthopedic surgery should be
consulted from the emergency department.

Volar fractures have been described as avulsion injuries involving the
palmar ulnar triquetral or lunotriquetral ligaments. These fractures are
unstable because of the ligamentous involvement and require expeditious
orthopedic referral. They are difficult to diagnose with plain radiographs and
often require magnetic resonance (MR) imaging to evaluate the extent of the
instability. When significant doubt exists as to the presence of a serious
injury and plain films are nondiagnostic, it is appropriate to immobilize the
wrist with a volar splint and arrange close orthopedic follow-up. If left
untreated, these patients develop arthritis and ligamentous instability.

Triquetral fractures (and other carpal bone fractures) are associated with
fractures of the distal radius. Therefore, one important pitfall for the
emergency physician is to forget to look for additional fractures in the same
extremity once one is identified.

Overall, triquetral fractures can be tricky to diagnose. Risks associated
with missed or delayed diagnosis include nonunion and vascular
compromise. If the mechanism of injury and physical examination are
concerning for a triquetral fracture but you don’t see a fracture on x-ray,
consider advanced imaging. If a distal radius fracture is present, make sure to
examine the hand to rule out concurrent carpal bone fractures.

KEY POINTS

The triquetrum is the second most common of the carpal bones to be
fractured.
Dorsal chip fractures can be diagnosed on lateral radiographs of the
wrist as a fleck of bone at the dorsum of the wrist. These do well with
simple immobilization.
Triquetral body and volar fractures can result from high-energy
mechanisms and are often associated with other bony or ligamentous
injuries. These are serious injuries that can result in morbidity. Prompt
orthopedic evaluation is important.
X-rays can be nondiagnostic for triquetral fractures. If injury is
suspected, patients can have their wrist immobilized in a volar splint
until orthopedic evaluation and/or advanced imaging can be obtained.

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SUGGESTED READINGS

Becce F, Theumann N, Bollmann C, et al. Dorsal fractures of the triquetrum: MRI
findings with an emphasis on dorsal carpal ligament injuries. AJR Am J
Roentgenol. 2013;200:608–617.

Komura S, Yokoi T, Nonomura H, et al. Incidence and characteristics of carpal
fractures occurring concurrently with distal radius fractures. J Hand Surg Am.
2012;37A:469–476.

Oh E, Kim HJ, Hong S, et al. Evaluation for fracture patterns around the wrist on
three-dimensional extremity computed tomography, especially focused on the
triquetrum. J Med Imaging Radiat Oncol. 2015;59:47–53.

Suh N, Ek E, Wolfe SW. Carpal fractures. J Hand Surg Am. 2014;39:785–791.

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294

LUNATE AND PERILUNATE
DISLOCATIONS: PICK THESE UP

ON INITIAL PRESENTATION!

TODD SCHNEBERK, MD, MA

Perilunate and lunate dislocations, although differing in radiographic
appearance, represent similar injuries along a continuum of carpal instability
with lunate dislocation representing a more severe ligamentous disruption
than does perilunate dislocation. Both dislocations are rare and can be easily
missed. They are also similar in terms of management and treatment
considerations. These two injuries embody the high-stakes nature of
emergency medicine; not recognizing them and failing to facilitate an
emergent reduction and expedient referral to a hand surgeon will result in
poor patient outcomes.

Perilunate and lunate dislocations occur most commonly in young men
around the age of 30, typically, as a result of hyperextension of the wrist with
ulnar deviation from a high-energy mechanism (motor vehicle accident, fall
from height, etc.). They should be considered as part of the differential
diagnosis of wrist pain in any patient with a fall onto an outstretched hand
(FOOSH) mechanism of injury. On physical examination, the wrist will
demonstrate significantly decreased range of motion and profound swelling
with diffuse tenderness to palpation. Patients are at risk of developing
compartment syndrome due to significant tissue edema. Associated median
nerve deficits can also be present, increasing diagnostic suspicion for
dislocation as the lunate lies dorsal to the median nerve and the displacement
that occurs in both injuries can result in subsequent nerve compression.
Moreover, multiple injuries may be present. For example, perilunate
dislocations are often accompanied by scaphoid fractures; initial focus on a

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seemingly isolated scaphoid fracture can result in the clinician missing a
more serious dislocation.

The lateral x-ray is the most useful view to diagnose a wrist dislocation
and to distinguish lunate from perilunate dislocation. Though it can be
somewhat confusing, the identification of these injuries is based on the
appearance of the lunate. In the lateral x-ray of a normal wrist, the radius,
lunate, and capitate are collinear with capitate on top of lunate, which in turn
sits on top of radius. Perilunate dislocation can be thought of as a capitate
translocation dorsally off of the top of the lunate. The lunate still articulates
with the radius inferiorly with only a slight volar rotation. On the other hand,
lunate dislocation represents a more extensive carpal and ligamentous
disruption. In this dislocation, the lunate is profoundly volar rotated and
displaced, no longer articulating with the radius. Yet, the capitate can remain
in nearly anatomic position collinear with the radius. This appearance is
known as the classic “spilled teacup” sign. The posteroanterior film, although
usually less useful than the lateral, will often show the lunate appearing
much more triangular than normal. This is named as the “piece of pie” sign,
and while it is beneficial if identified, it can occur in both lunate and
perilunate dislocations. Therefore, it is of little help when it comes to
distinguishing between the two compared to the lateral view (Figures 294.1
and 294.2).

Figure 294.1 Lunate dislocation. A: The lateral radiograph of the
wrist shows the lunate (L) tipped off of the distal radius, whereas the

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capitate (C) seems to be normally aligned in relation to the radius yet
is dislocated from the lunate. B:Anteroposterior view shows a pie-
shaped lunate (L) rather than a lunate with a more rhomboid shape. A
pie-shaped lunate on an anteroposterior view is diagnostic of a
perilunate or lunate dislocation. (From Brant WE, Helms CA, eds.
Brant and Helms Solution. Philadelphia, PA: Wolters Kluwer, 2005.)

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Figure 294.2 Perilunate dislocation. Although the lunate (L) is in a
normal relationship to the distal radius, the capitate (C) and the
remainder of the wrist are dorsally displaced in relation to the lunate.
(From Brant WE, Helms CA, eds. Brant and Helms Solution.
Philadelphia, PA: Wolters Kluwer, 2005.)

Once recognized, closed reduction is indicated prior to sending the patient
home. The technique for closed reduction of both of these dislocations is

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