Older Woman With Ankle and Chest Injury

A

69-year-old woman is broughtto the emergency department(ED) after a head-on collision in whichshe sustained injury to the right sideof the chest and the left ankle in additionto a laceration on her left forearm.She possibly had a transient loss ofconsciousness, but in the ED she canrecall all the events of the car accident.She complains of pain in the chestand ankle.

History

. Before the accident,the patient had been in good healthexcept for anxiety and hypothyroidism.Her present medications includeparoxetine (20 mg/d), alprazolam(0.25 mg tid), and levothyroxine(100 μg/d) plus liothyronine (25 μg/d)as thyroid replacement. She does notsmoke or use alcohol or illicit drugs.

Examination.

Temperature is37.5

^o

C (99.5

^o

F); pulse rate, 96 beatsper minute; respiration rate, 24 breathsper minute; and blood pressure,155/80 mm Hg. The patient appearsto be in mild to moderate distressfrom the pain of the chest injury. Thepain worsens with movement and respiration.Local tenderness is noted over the fourth to sixthribs at the anterior axillary line. Breath sounds are equalover both lung fields; compression over the spine andsternum causes pain to refer to the area of local rib tenderness.The abdomen and heart are normal. The neckappears to have sustained no traumatic injury and movesfreely without pain.The left ankle is swollen; an effusion is noted predominantlyover the anterior surface of the joint. Theankle itself appears stable when the integrity of the joint istested in the medial, lateral, anterior, and posterior directions.Capillary refill in the toes is of 2 seconds' duration; results of sensorimotor testing of the toes are normal.The patient is unable to bear weight on the affected ankle.Knees, hips, pelvis, and lumbar spine are free of traumaticinjury and tenderness.

Radiologic studies.

Cervical spine, chest, and leftankle radiographs are ordered. The cervical spine film isnormal and shows no fracture or subluxation. The chestfilm reveals a fracture of the right seventh rib withouthemothorax, pneumothorax, or pulmonary contusion.The ankle film is shown here.

What clues in this film suggest the cause of the anklepain and swelling?

IMPLICATIONS FOR PRACTICE

Causes of calcaneal fractures.

The calcaneus isthe most commonly fractured tarsal bone, and such fracturesaccount for 60% of all major tarsal bone injuries.Axial loading injuries (resulting from a fall from a heightor from an automobile accident) cause calcaneal fractures.Twisting injuries--such as those that occur with anklesprains--can also produce calcaneal fractures.

Associated injuries.

The majority of calcaneal fracturesinvolve direct axial compression. Because of thishigh-energy mechanism, associated injuries often occur;for example:

• 7% of calcaneal fractures are bilateral.
• 10% are associated with spinal injuries, typically vertebralcompression fractures.
• 25% are associated with other lower extremity injuries.¹

When you suspect a calcaneal fracture, examine thespine and the remainder of the lower extremity. Considerordering x-ray films of the spine or lower leg to detect anassociated occult fracture. Some experts recommend obtaininglumbar spine radiographs routinely in patientswith calcaneal fractures to rule out an occult lumbar compressionfracture.

Radiographic features.

Imaging of the calcaneuscan be difficult because of the complex 3-dimensional natureof its articulations. Calcaneal fractures are classifiedas intra-articular (75%) or extra-articular (25%), dependingon the extension of the fracture line into the subtalararticulation.The first step in the evaluation of a suspected calcanealfracture is to order standard foot and ankle radiographs.The anteroposterior view of the foot shows thecalcaneocuboid joint and the anterosuperior calcaneus,and the lateral view depicts the posterior facet and the calcanealbody. Lateral films are generally the most useful forassessing the calcaneus. If a calcaneal fracture is suspectedinitially, views of the calcaneus may be ordered as well.The lateral view is used to calculate Boehler's angle

(Figure 1B).

Calcaneal compression fractures are not alwaysobvious on plain radiographs, and calculation ofBoehler's angle can be helpful in determining the degreeof depression of bone fragments in intra-articular fractures.Normal Boehler's angle is 20 to 40 degrees.Fractures are occasionally best demonstrated on theaxial view of the calcaneus

(Figure 2).

Observe the generalshape of the bone; the presence of lucent or scleroticlines may indicate fracture. Disruption of the cortex andtrabecular pattern of the cancellous bone of the calcaneusmay also indicate fracture.

Role of CT and MRI in this setting.

Plain radiographycan underestimate the severity of calcaneal fractures.Thus, CT scanning has revolutionized the assessment of these fractures. Coronal and sagittal reconstruction imagesclearly display fracture fragments and their relationshipto the articular surface. MRI scanning also imagesthe talus and calcaneus and has a role in certain calcanealfractures.

Management.

The two assessments that are criticalto the management of calcaneal fractures are

¹

:

• The involvement of the subtalar joint.
• The degree of depression of the posterior facet.

Intra-articular or displaced calcaneal fractures mandateorthopedic consultation. Many orthopedists treatthese injuries with open reduction; however, the optimaltreatment is still undetermined, and numerous operativeand nonoperative approaches are used. If operative reductionis performed, the reduction must be as precise aspossible to obtain results superior to those of nonoperativeclosed reduction.Outpatient orthopedic follow-up may be arranged forthe patient with less severe calcaneal injuries. Initial immobilizationin a non-weight-bearing, below-knee, posteriorsplint stabilizes the fracture site and allows reduction ofedema and swelling in preparation for casting. For nondisplacedextra-articular fractures, a cast is usually applied for6 to 8 weeks.

Complications.

Minor extra-articular calcaneal fracturestypically heal without complication; however, significantcalcaneal fractures commonly are associated withcomplications. Compartment syndrome occurs in 10% of patients with calcaneal fractures, and the incidence of deformityand dysfunction among these patients is 50%.Overall, in both conservatively treated and surgicallytreated patients with calcaneal fracture, the incidence oflong-term pain, loss of joint mobility, and functional disabilityapproaches 50%.

²

KEY TAKE-HOME POINTS

• Calcaneal fractures represent significant impact injury,yet they often present in a relatively surreptitious fashionbecause of the difficulty in imaging the calcaneus. Calcaneusx-ray views and CT or MRI scans can be useful indetecting occult fractures.
• Diligently search for associated injuries, especially lumbarcompression fractures or fractures at other sites in thelower leg.
• To give patients a reasonable expectation of the longtermoutcome, advise them that calcaneal fractures carrya high attendant risk of chronic pain, deformity, and jointdysfunction.

References:

REFERENCES:

1.

Ho K, Abu-Laban R. Ankle and foot. In: Rosen P, Barkin R, eds.

EmergencyMedicine:

Concepts and Clinical Practice. St Louis: Mosby; 1998:821-855.

2.

Myerson M, Manoli A. Compartment syndromes of the foot after calcanealfractures.

Clin Orthop.

1993;290:142-150.