Fractures at the base of the fifth metatarsal have 2 common

types--tuberosity avulsion fractures and Jones fractures.

A tuberosity avulsion fracture occurs after an inversion injury

to the ankle (Figure 91-2). Patients will present with pain in

the lateral aspect of the foot that is worse with ambulation. By

contrast, a Jones fracture is a more distal fracture of the fifth

metatarsal shaft (within 1.5 em of the tuberosity). It occurs

when a laterally directed force is placed on the forefoot during

plantar flexion of the ankle.

DIAGNOSTIC STUDIES

...... Laboratory

Laboratory studies are usually not necessary when

evaluating patients with lower extremity trauma, although

they may be required for patients who need hospital

admission or operative management for their injuries.

Figure 91-2. Avu lsion fracture of the base of the

fifth metata rsa l.

..... Imaging

Plain radiography is the initial diagnostic imaging of

choice for any lower extremity injury. If a hip fracture is

suspected, adding an anteroposterior (AP) pelvis view to

the routine hip AP, internal, and external rotation views

enables the reader to compare the injured joint to the

unaffected side. This is especially helpful in patients with

severe degenerative joint disease. In elderly patients with

normal radiographs and persistent significant pain with

weight bearing, computed tomography ( CT) or magnetic

resonance imaging is useful for detecting an occult

fracture.

Routine knee radiographs include the AP, lateral, and

oblique views. In the setting of acute knee trauma, a

CHAPTER 91

patient meeting any of the criteria in the Ottawa knee rules

(age >55 years, isolated patella tenderness, fibula head

tenderness, inability to flex the knee to 90 degrees, and

inability to ambulate 4 steps after the injury and in the

emergency department [ED] ) should receive knee

radiographs. A high-riding patella on the lateral view indicates a possible patella tendon rupture. The presence of a

fat-fluid level (ie, lipohemarthrosis) on the lateral view is

an indirect sign of an intra-articular fracture. CT imaging

may be required for determining the extent of tibial plateau fractures. An avulsion fracture at the site of the

attachment of the lateral capsular ligament on the lateral

tibial condyle (ie, Segond fracture) suggests an anterior

cruciate ligament tear.

Ankle films include AP, lateral, and mortise views

(AP with 1 5 - to 20-degree internal rotation) . The

Ottawa ankle rules help dictate which patients need

ankle radiographs. Any patient unable to ambulate 4

steps after the injury or in the ED or who is t ender over

the posterior aspect of the medial or lateral malleoli

should have imaging. A lateral talar shift on the AP or

mortise views indicates a deltoid ligament rupture

(Figure 91-3). It is present when the space between the

medial malleolus and talus is greater than the distance

from the talar dome (superior aspect of the talus) to the

tibial plafond (inferior aspect of the tibia) . Fractures

may be isolated distal lateral malleolus, bimalleolar, or

trimalleolar (Figure 91-4).

Routine foot films are AP, lateral, and internal

oblique views. For foot injuries, the Ottawa foot rules

(ie, inability to ambulate 4 steps after the injury or in

the ED; or tenderness at the base of the fifth metatarsal

or the navicular) help determine which patients should

be imaged. If a calcaneus fracture is suspected clinically,

calculate Bohler angle on the lateral view to identify

subtle fractures and measure the degree of fracture

depression (Figure 91-5). The lines of this angle are

formed from the superior margin of the posterior

Figure 91-3. Lateral ta lar shift

indicating deltoid ligament disruption.

Figure 91-4. A bimal leolar fracture of the ankle.

tuberosity of the calcaneus through the superior tip of

the posterior facet and from the superior tip of the anterior facet to the superior tip of the posterior facet.

Normally, this angle is 20-40 degrees. If the angle is <20

degrees, an occult depressed calcaneus fracture should

be suspected.

On the AP view of the foot, the first 3 metatarsals

should align with the 3 cuneiforms, the fourth and fifth

metatarsals should align with the cuboid, and the medial

portion of the middle cuneiform should align with the

medial aspect of the second metacarpal. Any disruption to

this alignment suggests a Lisfranc fracture-dislocation, and

follow-up stress (weight-bearing) views should be obtained.

A Lisfranc injury is present if there is any b ony displacement

greater than 1 mm between the bases of the first and

second metatarsals.

.A Figure 91-5. The normal Bohler angle is between

20 and 40 degrees.

LOWER EXTREMITY I NJURI ES

PROCEDURES

Joint dislocations and displaced fractures should be

reduced in the ED to restore alignment and function.

Procedural sedation is often required to relax the large

muscle groups and facilitate manipulation of the bones

and joints. Fractures or dislocations that are difficult to

reduce with good alignment may require operative repair.

There are 2 common maneuvers for reducing hip

dislocations: the Allis and Bigelow maneuvers. In the Allis

maneuver, an assistant applies downward pressure to the

anterior superior iliac spines while the physician flexes the

knee and hip to 90 degrees. Grasping the knee with both

hands, simultaneously pull and rotate the femur laterally

and medially until the joint pops into place. In the Bigelow

maneuver, the patient is also placed in a supine position

with the affected hip and knee flexed to 90 degrees. Secure

the knee with a flexed elbow and grab the foot with the

opposite hand. Using the flexed elbow to apply traction to

the femur, externally rotate and extend the hip until the

femoral head reduces.

To reduce knee dislocations, apply gentle longitudinal

traction to the lower leg while an assistant provides

counter-traction on the thigh. Patella dislocations are

treated by flexing the hip, hyperextending the knee, and

sliding the patella back into place.

Arthrocentesis may be a therapeutic benefit in patients

with large knee effusions, although there is no good evidence of its efficacy and recurrence of the effusion can

occur. Diagnostically, the presence of blood and glistening

fat globules is pathognomonic of lipohemarthrosis, a sign

of an intra-articular fracture.

Ankle dislocation reduction is achieved by grasping the

heel and foot with both hands and applying downward

traction and rotation in the opposite direction to the

mechanism of injury.

MEDICAL DECISION MAKING

With any limb injury, the integrity of the neurovascular

status should be determined immediately (see Figure 90-7).

As mentioned previously, knee dislocations or severely

displaced tibia fractures may be associated with a popliteal

artery injury, so patients with those injuries should

undergo ABis ± evaluation with CT angiography. There is

poor collateral circulation around the knee, so the popliteal artery circulation must be restored within 8 hours to

prevent amputation.

Compartment syndrome also should not be missed

because it may develop after any traumatic injury. A tense,

severely swollen limb should have its compartment

pressures measured, along with serum creatinine

phosphokinase and myoglobin levels. Patients placed in a

splint after a sprain, nonoperative fracture, or reduced

dislocation should be discharged with instructions to

return for any signs or symptoms of compartment

syndrome.

TREATMENT

Emergent orthopedic consultation should be obtained for

compartment syndrome and all open fractures. Patients

with open fractures should be copiously irrigated in the ED

and given broad-spectrum antibiotics. For ligamentous

and meniscus injuries, tendon ruptures, and most

nondisplaced fractures, the joint or injured area should be

immobilized with a splint. Patients should be given

crutches for ambulation. Pain may be controlled with

narcotic analgesia for fractures and nonsteroidal antiinflammatory agents for soft-tissue injuries for several

days. Swelling is decreased with rest, ice, compression, and

elevation (RICE).

..... Hip And Femur Fractures

Fractures of the femoral head, neck, intertrochanteric, and

femoral shaft require admission for operative reduction

and internal fixation (ORIF). Hare traction splints can be

used temporarily to stabilize femoral shaft fractures during

transport (eg, prehospital setting), but are contraindicated

in femoral neck fractures because they can compromise

femoral head blood flow and cause avascular necrosis.

..... Knee Dislocation

In the setting of popliteal artery injury, operative repair

within an 8-hour time period is recommended. When

reduction has been achieved and vascular injury has been

excluded, immobilization and referral for surgery is appropriate.

..... Patella Fractures And Dislocation

Treated with analgesia, a knee immobilizer, and crutches

with weight bearing as tolerated. Orthopedic referral for

operative repair is indicated for displaced horizontal

patella fractures.

..... Patella And Quadriceps Tendon Rupture

Treated with analgesia, a knee immobilizer, and crutches

with weight bearing as tolerated. Orthopedic referral for

operative repair is indicated.

..... Tibial Plateau Fracture

Tibial plateau fractures may be immobilized in a long leg

posterior splint and referred for orthopedic evaluation

within 24-48 hours. These patients should be given

crutches and remain non-weight-bearing.

..... Ligamentous And Meniscal Injuries

Treated with analgesia, a knee immobilizer, and crutches

with weight bearing as tolerated. After 2-3 days of immobilization, patients should perform daily range of motion

exercises (ie, 10-20 knee flexions and extensions 3-4 times

a day) to prevent contractures and maintain mobility.

CHAPTER 91

Orthopedic referral for possible operative repair is indi ­

cated.

� Tibia Fractures

Because the tibia is the weight-bearing bone of the lower

leg, many tibia fractures are admitted for operative repair.

These patients have a high risk of developing compartment

syndrome.

� Ankle Sprain

Grade I ankle sprains should be immobilized for 1-2 days

in an ankle brace followed by early range of motion and

strength training exercises. Grade II and III ligamentous

injuries should be stabilized in a short leg splint with the

ankle in a neutral position.

� Achil les Tendon Rupture

Support the ankle with a short leg posterior splint and refer

to an orthopedist for operative repair, the preferred treatment for young or more active patients. The ankle is

immobilized in slight plantarflexion.

� Ankle Fractures And Dislocation

Operative repair is the preferred treatment for ankle dislocations and unstable ankle fractures. Bimalleolar and trimalleolar fractures are unstable injuries that are typically

reduced in the ED, if needed, and referred for operative

repair. An isolated distal lateral malleolus fracture is con ­

sidered to be a stable injury that can be immobilized in a

short leg posterior splint and referred for orthopedic follow-up.