Case:

A 54-year-old male presented to the ED after falling from a 10-foot ladder while painting his home. He complains of left foot pain, especially in the heel. Examination reveals edema of the left posterior foot, and he is unable to bear weight. 

A fracture of the calcaneus can be a painful and devastating injury. Although uncommon, calcaneal fractures can lead to long-term disability. Physical examination of the ankle can be misleading and radiographic evidence can be difficult to interpret making a high index of suspicion in the right clinical setting important. The most common mechanism for a calcaneal fracture is high-energy trauma to the foot. Seventy-two percent of these fractures result from falls, [i] but other high-energy mechanisms, such as motor vehicle crashes, can also cause calcaneal injury.  

Types of Calcaneal Fractures:

There are two broad categories of calcaneal fractures: extra-articular and intra-articular:

25-30% of fractures are extra-articular. All fractures that do not involve the posterior facet are included in this category. These include calcaneal tuberosity avulsion fractures and extra-articular Lover’s fracture. The name is derived from the fact that a suitor may jump from the bedroom window while trying to escape from the lover's spouse.    

Calcaneal fractures are more frequently intra-articular, involving the subtalar joint (the calcaneus and the talus form the subtalar joint). A lover fracture may be intra- or extra-articular.

Clinical Presentation:

Patients often present after a fall from a height with complaints of heel pain and swelling. Examination of the patient with a foot or ankle injury follows the standard approach; inspection, palpation, range of motion testing, etc.  The heel may appear short and wide when compared to the non-injured foot. A hematoma extending to the sole of the foot is called "Mondor Sign" and is highly suspicious for calcaneal fracture. Remember to closely examine the skin for lacerations, blisters, and tenting.

Imaging:

Fractures of the calcaneus can be very subtle, and these fractures often are missed on radiographs. When the mechanism of injury or exam is highly suggestive of calcaneus fracture, lateral radiographs should be evaluated by measuring Bohler's angle or the critical angle of Gissane. The axial (Harris) view of the foot may demonstrate widening of the heel or lateral wall displacement. This view should be obtained if the standard films are negative but strong clinical suspicion exists. Comparison views are helpful if the diagnosis remains in question.

It is also important to differentiate calcaneal fractures based on whether they are intra-articular or extra-articular, and displaced or nondisplaced, as these findings will dictate treatment. CT imaging is often necessary to better define the extent of the fracture. Multiple classification schemes have been used for calcaneus fractures, the most popular of which is the Sanders classification system used to describe intra-articular calcaneal fractures. This classification is based on the number of intra-articular fracture lines and their locations on CT imaging. Type I fractures are non-displaced. Type II have two articular fragments. Type III has three articular fragments. Type IV fractures have more than three articular fragments and are highly comminuted. [ii]  

MRI has a limited but potentially important role in select cases. If an occult non-displaced calcaneus fracture is suspected (e.g., persistent symptoms plus suggestive but indeterminate findings on CT), MRI may be used to confirm or rule-out a fracture. MRI is also sensitive for detecting stress fractures of the calcaneus.

Bohler's Angle:

On lateral radiograph, Bohler's angle is the angle between two tangent lines drawn across the anterior and posterior aspects of the superior calcaneus on the lateral view. A Bohler angle of less than 20° suggests calcaneal fracture[iii], though a normal Bohler angle does not exclude fracture.

Critical Angle of Gissane:

Measured on lateral radiograph, this “critical angle” is formed by the downward and upward slopes of the calcaneal superior surface. A normal angle of Gissane measures between 100 and 130 degrees, with a greater angle indicating fracture of the posterior subtalar articular surface.

In 2006, Knight et al. published a randomized case-control trial evaluating the use and aid of Bohler’s angle and critical angle of Gissane. Of emergency department physicians studied, 97.9% were able to make an accurate diagnosis of calcaneus fracture without the benefit of measuring either angle on lateral radiograph. [iv]

Case Continued:

Our patient is also complaining of low back pain in addition to his heel pain. Examination of the lower back reveals axial lumbar tenderness without neurologic deficits.

Consider Associated Injuries:

Patients with calcaneus fractures often have concurrent injuries, and it is important to consider this possibility in their evaluation. Following major trauma, an obvious deformity of the hindfoot or ankle injury may distract us from these other injuries.  In addition to bony injuries, the amount of force required to fracture the calcaneus can cause damage to the surrounding soft tissues. Patients can develop compartment syndrome in the “calcaneal compartment” which, if left untreated, can lead to claw toe deformity. Up to 10% of calcaneal fractures will develop compartment syndrome and half of these can develop foot deformities, including clawing of the toes. [v]

High-energy impact to the feet can be accompanied by other lower extremity fractures in 25% of patients, vertebral injuries in 10% of cases, and contralateral calcaneus injuries in 7%.[vi] The mechanism of injury often involves a substantial load to the axial skeleton, such as jumping from a second story window. Therefore, a careful and focused spine evaluation is warranted. A thorough and focused tertiary survey should aim to rule out other injuries in common areas, in particular the thoracolumbar spine.

Figure 5: L1 Burst Fracture. http://radiopaedia.org/cases/calcaneal-fracture-and-associated-spinal-injury

Treatment:

Nondisplaced fractures (Sanders Type I) can be treated nonoperatively. In general, patients should be placed in a bulky compression dressing (Jones dressing) until the initial swelling subsides. The dressing can then be replaced by a removable splint or boot to begin range-of-motion exercises of the ankle and the subtalar joint. Non-weight-bearing for at least 6 weeks after injury is recommended.

Displaced intra-articular fractures require surgical intervention, and it is important to arrange for prompt orthopedic follow-up. Emergent orthopedic consultation is required for open fractures, fractures associated with neurovascular injury, fractures associated with dislocation (which must be reduced immediately), and suspicion or diagnosis of acute compartment syndrome.

Figure 6: Surgically repaired calcaneal fracture. http://orthoinfo.aaos.org/topic.cfm?topic=A00524

The Take Home:

• Physical examination of the ankle can be misleading and radiographic evidence can be difficult to interpret. It is important to have a high index of suspicion for calcaneal fracture in the appropriate clinical setting.
• Bohler’s angle can be used to identify subtle fractures. Less than 20 degrees is consistent with a calcaneus fracture.
• CT is the imaging modality of choice in evaluating calcaneal fractures.
• ED physicians should always consider the possibility that calcaneus fractures can be bilateral and associated with other lower extremity fractures and/or thoracolumbar spine fractures. 
• An important early complication is acute compartment syndrome.
• Emergent orthopedic surgery consultation is necessary for intra-articular, open, or displaced calcaneal fractures.
•  

Reviewed by Dr Jeffrey Feden, Attending and Assistant Professor and Dr Neha Raukar, Attending, Assistant Professor and Director, Division of Sports Medicine, Department of Emergency Medicine, Alpert Medical School of Brown University.

References:

[i] Mitchell MJ, McKinley JC, Robinson CM. The epidemiology of calcaneal fractures. Foot (Edinb). 2009 Dec;19(4):197-200. doi: 10.1016/j.foot.2009.05.001. PubMed PMID: 20307476.

[ii] Daftary A, Haims AH, Baumgaertner MR. Fractures of the calcaneus: a review with emphasis on CT. Radiographics. 2005 Sep-Oct;25(5):1215-26. Review. PubMed PMID: 16160107.

[iii] Isaacs JD, Baba M, Huang P, Symes M, et al. The diagnostic accuracy of Böhler's angle in fractures of the calcaneus. J Emerg Med. 2013 Dec;45(6):879-84. doi: 10.1016/j.jemermed.2013.04.055. Epub 2013 Sep 17. PubMed PMID: 24054885.

[iv] Knight JR et al. Boehler’s angle and the critical angle of Gissane are of limited use in diagnosing calcaneus fractures in the ED. 2006. Am J Emerg Med, Jul; 24 (4): 423-427.

[v] Germann CA, Perron AD, Miller MD, Powell SM, Brady WJ. Orthopedic pitfalls in the ED: calcaneal fractures. Am J Emerg Med. 2004 Nov;22(7):607-11. Review. PubMed PMID: 15666272.

[vi] Weedier IS, Charted J: Emergency Department Evaluation and Treatment of Ankle and Foot Injuries. Emergency Medicine Clinics of North America 2000;18:85-113.