Calcaneal Fractures

Calcaneal fractures have a track record of being difficult to treat and have frustrated doctors for years. The calcaneus is much like an egg; an outer firm shell and soft on the inside. As a result, the calcaneus often shatters when broken. Calcaneal repair not only requires re-apposition of multiple fracture patterns, but also requires restoration of the subtalar joint. The subtalar joint is the interface between the calcaneus and talus and is a primary load bearing joint of the foot. In some cases, the calcaneal-cuboid joint may also be affected by an extensive fracture pattern.

Three classifications are used to describe calcaneal fractures. The Essex-Lopresti classification describes subtalar joint depression fractures (very severe fractures) in a bit more detail than the more commonly used Rowe classification. A third, and newer classification proposed by Sanders in 1993 uses CT scanning to determine the stage of calcaneal fracture. Plain x-rays and CT scans are often used to determine the extent and classification of calcaneal fractures.

The Essex-Lopresti Classification Of Calcaneal Fractures

Type A - Tongue type
Type B - Joint depression type

The Rowe Classification Of Calcaneal Fractures

Type 1a - Tuberosity fracture medial or lateral
Type 1b - Fracture of the sustentaculum tali
Type 1c - Fracture of the anterior process of the calcaneus
Type 2A - Beak fracture of the posterior calcaneus
Type 2b - Avulsion fracture involving the insertion of the tendo-Achillles
Type 3 - Oblique fracture not involving the subtalar joint
Type 4 - Body fracture involving the subtalar joint
Type 5 - Body fracture with subtalar joint depression and comminution

The Sanders Classification Of Calcaneal Fractures

Type I fractures are nondisplaced.
Type II are two-part or split fractures
Type III are three-part or split depression fractures.
Type IV were four-part or highly comminuted articular fractures.

Stress fractures of the calcaneus

Stress fractures of the calcaneus are the result of a sudden abrupt injury but can occur without a history of trauma. The most common injury seen our practice is a fall from a height of more than 6 feet. A stress fracture of the calcaneus is a condition that is often overlooked as a differential diagnosis of heel pain. Plantar fasciitis (also called heel spur syndrome) is so common that most health care providers will defer to plantar fasciitis as a primary diagnosis when evaluating heel pain. A good patient history, and particularly one that notes the onset and character of the pain, is very important when differentiating between plantar fasciitis and calcaneal stress fractures.

The diagnosis of calcaneal stress fractures can be difficult at times. Stress fractures, regardless of where they occur in the body, are different than what we would tend to think of when we discuss fractures. The appearance of a stress fracture on x-ray is not always evident. Quite often, the only x-ray findings that we'll see are those signs that show up towards the end of the healing process, sometimes as long as several months after the onset of the injury. We don't actually visualize the fracture, but rather we see the calcification that occurs in the late phases of the healing process. Should the symptoms of heel pain not respond to treatment for plantar fasciitis, or initial clinical findings seem suggestive of a stress fracture, there are several tools that can be used to help differentiate between calcaneal stress fractures and each of the other common conditions considered in treating heel pain. These tools include plain x-ray, bone scans, CT scanning and MRI.

• Plain x-rays may be able to visualize a calcaneal stress fracture, but quite often due to the lack of disruption of the bone, plain films lack the ability to 'see' the fracture. As fractures heal, many times the healing process can be seen on plain x-ray films. The healing process will increase the amount of calcium surrounding the fracture. This increase in calcium is called bone callus. The formation of bone callus typically takes about 4-6 weeks to see on plain x-ray, therefore, periodic follow-up x-rays may aid in diagnosing a stress fracture of the heel. Additional finding may include radiolucency (darkening) of the x-ray in the early stages of fracture repair.
  

• A three phase technetium bone scan can help differentiate the location and degree of inflammation in the calcaneus thereby helping to diagnose a calcaneal stress fracture. Bone scans are tests that utilize a radioactive nucleotide injected into the patient to identify areas of inflammation. A scan is taken of the injured area three times over the course of three hours. Each of the scans show a different degree of inflammation based upon the increased blood flow to the inflamed area. In the case of a calcaneal fracture, a bone scan can help in many ways. First, the scan will locate the area of the fracture based upon the inflammation seen in fracture healing. Second, the bone scan will help to differentiate between many other potential problems of the heel such as plantar fasciitis. And lastly, a scan can help to determine the acuteness of the injury. For instance, we may see a questionable area on an x-ray but we will not be able to tell whether the suspected injury is old or new. The bone scan will help us in that a new injury will 'light up' on the scan due to its' current inflammation. An old injury on the other hand will not 'light up' on the scan due to its' lack of current inflammation.
  

• CT (computerized tomography) scanning is a test that performs a series of x-ray slices or cuts through the calcaneus. Computer software organizes these images in a way so that we can see a series or progression of change through the heel. CT scanning is particularly useful for defining contrast. Although not considered the best testing modality for calcaneal stress fractures (Sanders Stage I), CT scanning is the best tool for displaced calcaneal fractures (Sanders stage II-IV)
  

• MRI's are also helpful in differentiating calcaneal fractures from plantar fasciitis. MRI's can identify small areas of bone edema suggestive of a fracture. Often, due to the cost of an MRI, insurance companies will request a bone scan of the heel prior to approving a more costly MRI.

Treatment of calcaneal fractures

Non-displaced calcaneal fractures (Sanders Stage I) require a period of rest and partial to complete immobilization. Treatment options include hard casts or removable cam walkers. The duration of symptoms and time necessary for adequate healing varies with the age, nature of the fracture and general health status of the fracture. It is not unusual to find calcaneal fractures that are symptomatic up to 4-6 months post injury.

As previously mentioned, displaced calcaneal fractures (Sanders Stage II-IV) can be very difficult to manage. Closed reduction (manipulation of the fracture under anesthetic without surgery) can be successful in treating calcaneal fractures. The success of closed reduction depends upon the stage of calcaneal fracture. Open reduction, often called ORIF or open reduction with internal fixation, is what doctors use when closed reduction fails to reduce the fracture. Open reduction is not guaranteed to produce more successful outcomes compared to closed reduction.

The decision when to perform ORIF for calcaneal fractures varies. Some doctors prefer to act as soon after the injury as possible, while others prefer to wait 1-2 weeks following the injury using a fracture pillow to allow for the initial phase of inflammation to subside. Follow-up post reduction (whether close or open) varies but will include a period of non-weight bearing, splinting or casting to allow for fracture healing.

In severe cases of joint depression fractures (Sanders Stage 3 and 4) additional surgery may be required to fuse the subtalar joint. If the subtalar joint is significantly damaged in the injury, fusion of the subtalar joint is the only solution. Most doctors will stage these procedures, performing a subtalar fusion long after the immediate trauma of the injury. In severe cases of subtalar joint disruption where degenerative arthritis is inevitable, subtalar joint fusion may be advocated during ORIF of the calcaneal fracture.

The photos below show ORIF (open reduction with internal fixation) of a Sanders stage 4 fracture. Images 1 and 2 show the approach to the calcaneus, isolating the sural nerve in the lateral heel. Image 3 shows dissection of the subtalar joint. Image 4 shows the calcaneal cuboid joint. Images 5 and 6 show reduction of the fracture and partial fixation. Images 7 and 8 show closure and drain placement prior to placement in a compression splint.

Calcaneus - the bone of the heel.

Calcaneo-cuboid joint - joint found between the calcaneus and cuboid bones.

ORIF - open reduction with internal fixation.

Subtalar Joint - (STJ) the joint between the two major bones of the rearfoot, the talus and calcaneus. The STJ is a common site of residual arthritis following calcaneal fractures.

Technetium - a radioactive substance that is attracted to area of inflammation. Used as the active substance in bone scans.

The calcaneus is surrounded by a very firm outer surface of cortical bone. The inside of the calcaneus is soft and spongy consisting of softer cancellous bone. This architecture is much like an egg; hard on the outside and very soft in the center. And just like an egg, the calcaneus is very susceptible the crush injuries.

The calcaneus is an unusually shaped bone with numerous surfaces making up the support for the subtalar joint and the calcaneal cuboid joint. Numerous tubercles project from the calcaneus enabling the attachment of ligaments, retinaculum, fascia and muscles.

The dorsal, or top surface of the calcaneus is covered with an articular surface that makes up the calcaneal side of the subtalar joint. The cortical bone supporting the subtalar joint is quite thick and accustom to repetitive load. The subtalar joint actually consists of three separate joint surfaces; the anterior, middle and posterior facets. The anterior and middle facets are the two smaller facets of the subtalar joint. The anterior and middle facets are separated from the posterior facet by the sulcus calcanei. The posterior facet of the subtalar joint is the largest of each of the facets. The posterior facet slopes obliquely up and away from the sinus tarsi.

Radiographic anatomy of the calcaneus includes a number of important findings that are used to evaluate calcaneal fractures. The subtalar joint facets create an angle that is used to determine the extent of joint depression fractures. This angle is called The Angle of Gissane, or The Crucial Angle of Gissane. The normal measurement of this angle is 120-145 degrees. An increase in The Crucial Angle indicates a joint depression fracture of the calcaneus.

Immediately below The Angle of Gissane is a radiolucent area of the calcaneus called the neutral angle. The neutral angle is a divergence of trabecula away for the subtalar joint. The neutral angle is considered the weakest aspect of the calcaneus and is very susceptible to fracture when axial load is applied from the talus.

An important anatomical consideration in calcaneal fractures is the soft tissue envelop that is present surrounding the heel. This soft tissue envelop consists of tendons that traverse the calcaneus and an extensive series of ligaments on the medial, lateral and plantar sides of the calcaneus. A number of muscles attach to the plantar, or bottom of the calcaneus that also act to maintain the basic structure of the calcaneus during and following injuries. In the event of a calcaneal fracture, the soft tissue envelop encloses the fracture. Compound fractures of the calcaneus are rare due to the presence of this soft tissue envelop.

The biomechanics of calcaneal fractures are determined based upon three factors. Those factors include (1) the position of the foot at the time of injury (2) the direction in which force is applied to the calcaneus at the time of injury and (3) the ability of the calcaneus to withstand force. The combination and extent of axial load and shear force is what defines each calcaneal fracture.

The majority of calcaneal fractures occur as the result of a fall from a height. When the heel strikes the ground, the mass of the body continues to drive force down towards the ground, and in many instance, through the calcaneus.  This force is called axial force or axial load.  The primary fracture line, or most significant location of the break in the calcaneus, is defined by axial load.

If the heel is inverted (soles facing each other) or everted (soles away from each other) at the time of injury, then axial force cannot be driven directly to the ground.  This deviation of axial force creates a second load called shear force or shear load.  Shear load will force the load to deviate from the primary fracture line and creates a series of secondary fracture lines.

Calcaneal stress fractures may follow fracture patterns as defined by our classifications, or may deviate based upon the cause of the injury.  Stress fractures are common in sports like soccer and basketball, particularly in athletes who are beginning training.  This particular type of calcaneal stress fracture is due to excessive repetitive loading.  Calcaneal stress fractures can also be due to a single traumatic event such as a fall or contusion.

Calcaneal fractures come in all shapes and sizes. Some are quite obvious and severe while others are less obvious and more difficult to diagnose. The symptoms of a calcaneal fracture following a fall include (1) inability to bear weight on the heel (2) swelling of the heel and (3) bruising of the heel and ankle. Pain is usually severe enough to warrant a visit to your local emergency room for care.

Calcaneal stress fractures on the other hand, are much different in their presentation. Patients who have sustained a calcaneal stress fracture may or may not remember an incident of trauma. Calcaneal stress fracture pain begins with initial weight bearing and continues throughout the day. Pain is described as dull achy pain. Pain is usually present with compression of the medial and lateral walls of the heel. Bruising may or may not be present in a calcaneal stress fracture. Continued pain usually motivates a patient to visit their doctor where x-rays are taken. X-rays for calcaneal stress fractures are often inconclusive. As symptoms persist, an MRI is used to identify what radiologists call bone edema, or swelling within the bone. Bone edema is the marker that pinpoints a calcaneal stress fracture. Symptoms of calcaneal stress fractures may persist for 6 months or more.

Symptoms of a traumatic calcaneal fracture (Sanders Stage II-IV) following a fall or other injury are quite obvious. Therefore calcaneal fractures that are the result of a fall have no differential diagnosis knowing that the injury was directly related to a fall.

The differential diagnosis of calcaneal stress fractures includes:

Baxter's nerve entrapment - an entrapment of the recurrent branch of the posterior tibial nerve.

Gout - deposition of monosodium urate crystals (hyperuricemia).

Heel spur syndrome - see plantar fasciitis.

Plantar fasciitis - a common condition of the heel that results in pulling by the plantar fascia and a tearing pain at the attachment of the fascia on the bottom of the heel. Pain is severe with the first few steps out of bed in the morning or after a brief period of rest.

Retrocalcaneal bursitis (Albert's Disease) - this is the formation and inflammation of a bursa at the back of the heel between the heel bone and Achilles tendon.

Rheumatoid arthritis

Septic Arthritis

Sero-negative arthropathies such as Reiter's Syndrome.

Sever's Disease - and inflammatory condition typically found in young over weight boys age 10 to 15 years old.

Tarsal Tunnel Syndrome - also known as posterior tibial nerve neuralgia. Tarsal Tunnel Syndrome (TTS) characteristically has pain that does not decrease with rest. Also, TTS often presents with numbness or 'tingling' of the toes.

• Plantar Fasciitis

• Severs Disease

• Talar Dome Fracture

• Heel Spur Syndrome

• CT Band Syndrome

This article was written by Jeffrey A. Oster, DPM and last updated 2/5/13.