A Guide To The Differential Diagnosis Of Heel Pain

Although plantar fasciitis is the most common cause of heel pain, one should not overlook other possible etiologies. Accordingly, this author reviews pertinent keys to the patient history, physical exam and diagnostic testing that can help facilitate an accurate diagnosis.

   Plantar fasciitis is by far the most common cause of heel pain. Given the high number of cases reported per year, it is not uncommon for a doctor to diagnose a patient with plantar fasciitis without paying adequate attention to other potential causes of heel pain.

   It is essential for foot and ankle specialists to consider the range of possible causes prior to coming to a conclusion on the etiology of heel pain in any patient.

   Plantar fasciitis involves an inflammation and micro-tearing of the plantar fascia along its course. Plantar fasciitis is most commonly painful in the heel region at the attachment of the fascia to the plantar calcaneus.

   Patients will often complain of pain with the first steps in the morning or after sitting for a period of time and then standing. After a period of walking, the fascia tends to stretch out and there is far less pain. The problem can have a rapid onset and be very painful in a short period of time.

   However, plantar fasciitis may also be slow to progress and gradually increase in severity. Often patients will note that plantar fascia and/or Achilles stretching, or improved quality in shoewear will decrease their pain. Insoles or orthotics may also help to decrease pain.

   It is rare to see a patient with plantar fasciitis present shortly after he or she has experienced the pain. Most commonly, patients present after trying multiple home therapies and experiencing weeks to months of chronic low-grade pain.

   The only time that a patient will present with acute plantar fascia pain is when he or she has an actual fascia tear. This usually occurs with intense exercise and can be associated with or without previous plantar fascia pain. In such a patient, the pain is very severe and very rapid in its course. The patient may have noted a “pop” at the time of injury and may have pain at all times with ambulation.

   Although plantar fascia problems are the most common presenting factors with heel pain, there are a variety of other etiologies that are commonly associated with heel pain and are often misdiagnosed as plantar fasciitis. A short list of these etiologies includes:

   • plantar fascia tear
   • tarsal tunnel syndrome
   • Baxter’s nerve entrapment
   • calcaneal stress fracture
   • calcaneal cysts
   • soft tissue mass
   • short flexor tendon tear
   • gout
   • systemic arthritis (lupus, rheumatoid arthritis, psoriatic arthritis)

   Although one may note other causes of heel pain such as Achilles tendonitis/tendinosis, sural nerve entrapment or peroneal tendon tear, these problems are in different areas of the heel and are far more simple to diagnose.

   Accordingly, let us take a closer look at the most common causes of plantar heel pain.

Emphasizing The Value Of The Patient History

   A comprehensive patient history is essential to getting an early idea about the possible cause of the heel pain.

   How long has the patient had the problem? How often does the pain occur and for how long does it last? What improves the problem or makes it worse? What types of treatment has the patient previously attempted and have the treatments been helpful? Was there any associated trauma? Is there a family history of heel pain and/or a systemic arthritic condition?

   After gathering all the information, there are several considerations. The first point to consider is how long the pain has been present. If the pain is acute, the more common issues are traumatic such as stress fracture, gout or plantar fascia tear. A nerve irritation is also a consideration albeit a less likely one.

   Proceed to consider the duration of the pain and how long the pain lasts at a given time. When the pain only lasts a short time and then improves with ambulation, consider plantar fasciitis, systemic arthritic heel pain and mild cases of nerve entrapment. When the pain lasts for a long time or is chronic with ambulation, consider nerve entrapment, fracture, cyst or plantar calcaneal tendon tear.

   Often what makes the pain better or worse may give the best information in the patient history. In cases of fasciitis and systemic causes of heel pain, a short period of ambulation improves the condition. In cases of fracture, soft tissue masses, calcaneal cyst, nerve entrapment, tendon tear or fascia tear, the pain gets worse with increased activity.

   Stretching and insoles will rarely improve a calcaneal cyst, fracture or tendon tear while these same treatments can help address symptoms of nerve pain, fasciitis or systemic sources of pain. Antiinflammatory treatments can improve almost all of the above conditions or mask pain, and are not of much help in our diagnostic workup.

   Finally, trauma and family history are very helpful. Traumatic causes of heel pain include fracture, tendon tear or fascia tear. If there is a family history of systemic ­­arthritic conditions, this can be very useful information in the diagnostic workup.

What To Look For In The Physical Exam

   The physical exam of the lower extremity is comprehensive and often divided into four categories: dermatologic, neurologic, vascular and muscular testing.

   The vascular testing of the dorsalis pedis and posterior tibial pulses is important to rule out poor vascular supply when it comes to possible surgical treatment. However, poor vascular supply is not a common source of heel pain.

   The dermatologic exam is important with regard to any form of soft tissue masses and for signs of a potential systemic condition such as psoriatic arthritis or rheumatoid arthritis. If flaky skin and patches of abnormal skin are visible about the ankle, knees, elbows and hands, one must suspect psoriasis. Further dermatologic examination is necessary to gauge the quality of skin in case surgery is required. The physician must consider vascular abnormalities such as varicosities and ulcer regions in the skin evaluation as they may be problems in the healing process.
The neurologic conditions that one must consider typically involve the medial ankle but there may also be some associated lateral pain. The first test is examining the tarsal tunnel for a positive Tinel that radiates into the foot or just to the heel. If the pain radiates to the heel area, perform a more distal examination of the calcaneal branch and more specifically the lateral plantar nerve branch. If a Tinel of the more distal nerve region is present, one may suspect both tarsal tunnel and calcaneal nerve entrapment.

   The calcaneal branch of the lateral plantar nerve runs plantar to the heel spur and plantar fascia insertion site on its way to the lateral heel. In certain patients, heel pain in the plantar heel with a tingling to the central or lateral heel may be the only source of pain associated with calcaneal nerve entrapment. In such cases, the pain is often a burning pain that radiates to the lateral heel area with pressure on the plantar heel area.

   During the neurologic testing, the physician must consider varicosities and possible soft tissue masses in the region of the tarsal tunnel pressing on the nerve. Varicosities or a possible soft tissue mass may be the underlying cause of nerve pain related to the associated heel pain.

   The most important part of the exam process is muscular testing. Start at the knee by checking the gastrocnemius tendon. Proceeding distally, test the Achilles, calf muscle and posterior compartment muscle for contracture and equinus. Then test the ankle for bony equinus, degenerative conditions and instability.

   It is important to consider that some cases of plantar heel pain and plantar fasciitis can be secondary to ankle instability with associated peroneal contracture causing pronation of the foot and medial heel overload.

   Proceed to examine the plantar heel. Pain with plantar fasciitis is most common on the medial calcaneal tubercle. In rare cases, there may be pain in the lateral column. Arch pain may be associated with fascia or tendon overload. However, it can also be the result of nerve pain and swelling from a medial ankle nerve entrapment.

   An excellent test for fracture or calcaneal cyst pain is a squeeze test of the heel. Perform the squeeze test with both palms, gently pressing both medially and laterally on the heel. If there is associated pain, consider nerve conditions, stress fracture or cyst formation in the heel region.

   A second test for a stress fracture is pressing on the area of greatest tenderness with a tuning fork. In the case of fracture or, to a lesser degree, a calcaneal cyst, there is often an increase in pain.

   Finally, in the case of cyst or fracture problems, a swelling of the heel region is often present. Palpate the heel area and compress the soft tissue gently to check for any forms of soft tissue mass. One may note masses in the plantar, medial or lateral heel area. Often the mass is palpable with gentle pressure.

   Tendon tears in the heel area are often associated with low- or high-energy trauma cases. The short muscles that are attached to the plantar heel area can tear and be very similar in the origin of pain as plantar fasciitis. The difference is that the pain is often more intense in early cases prior to scar formation and does not improve with ambulation. Flexion of the toes against pressure can cause pain due to muscle contracture in a partially torn muscle that originates from the heel area.

   It is very rare to see a case of gout in the heel area. In such a case, the findings (including a red, hot, swollen area) are similar to what one might see with signs of infection. In cases of gout, the skin is often shiny and swollen, and there is a high level of pain with a fairly rapid onset.

Pertinent Pearls On Diagnostic Imaging And Testing

   When it comes to diagnosing heel pain, one can test for nerve problems, muscular problems or systemic problems. It is essential not to limit the testing options to what is available in the office. Utilize the test that will most likely deliver the best information about the underlying source of pain.

Commonly utilized imaging and/or tests include:

   • standard foot/ankle radiographs (X-rays)
   • magnetic resonance imaging (MRI)
   • computed tomography (CT)
   • three-phase bone scan
   • diagnostic ultrasound
   • nerve conduction velocity testing (NCV)
   • electromyelogram testing (EMG)
   • neurosensory testing

   Radiographs. In general, one obtains radiographs on the initial visit. In certain cases, the radiograph can reveal a stress fracture, calcaneal cyst or pertinent information with regard to a systemic source of heel pain with plantar and posterior spurring. However, just because there is plantar and/or posterior spurring, do not assume that the source of pain is plantar fasciitis.

   Radiographs allow you to check foot alignment and any forms of arthritis or bone spurring. In general, though, if you suspect a cause of heel pain that radiographs do not easily show, further testing is necessary.

   Three-phase bone scans. Three-phase bone scans can detect regions of uptake in inflammatory processes. The main advantage of a bone scan is that it is relatively cheap and simple to perform. My biggest problem with bone scans is that the information from a bone scan is non-descriptive and non-specific. For example, there is not a good way to differentiate between a plantar fasciitis that is severe at the heel insertion and a mild calcaneal stress fracture.

   A bone scan is an excellent tool to help pinpoint the area of greatest pain in feet that are diffusely painful.

   Computed tomography. A CT scan of the foot is an excellent source of information for arthritis cases, calcaneal cysts and stress fractures. In addition to showing fractures and bone cysts, CT scans can also reveal subtalar, ankle and midtarsal arthritis conditions that may be sources of abnormal gait and plantar heel pain.

Assessing The Pros And Cons Of Diagnostic Ultrasound

   Ultrasound. Diagnostic ultrasound is a non-painful, cheap and effective form of testing for soft tissue problems in the hindfoot. In-office ultrasound can be overutilized and that has been a problem for certain patients who have been treated previously at other locations prior to coming to our institute.

   However, when one uses diagnostic ultrasound properly, the physician can easily check the plantar fascia along its entire course and note both fasciitis and fasciosis regions. Furthermore, ultrasound can easily detect tears of the fascia.

   While difficult, it is possible to diagnose tendon tears about the plantar heel. Often, these tears are very small and may go undetected if the person performing the test is not well versed in diagnostic ultrasound testing.

   Ultrasound may also pick up stress fractures as well as calcaneal cysts. However, bear in mind that ultrasound testing is a fairly poor primary test for these conditions. If you suspect stress fractures and calcaneal cysts, perform additional testing.
Physicians may also use ultrasound to help detect soft tissue masses or nerve compartment masses. You can also employ ultrasound to check the medial nerves for compression.

   One source of heel pain that is difficult to diagnose is flexor hallucis tendon stenosis (also known as an accessory flexor tendon), which causes a crowding of the tarsal tunnel. Flexor hallucis tendon stenosis may cause medial ankle pain, medial heel pain and even nerve problems. It is best to perform dynamic muscle testing along the posterior ankle, medial heel and plantar heel with diagnostic ultrasound. As the foot moves, image the tendon or muscle of concern to check for tear, stenosis or possible accessory muscle findings.

What About Magnetic Resonance Imaging?

   Magnetic resonance imaging. This is the most common adjunct testing we perform at our facility for unusual heel pain that needs additional workup.
For most differential diagnosis workups of unusual heel pain, one can employ MRI as first-line imaging in that it will provide the best source of information.
Whether there are tendon and fascia injuries, fracture and cyst formation, unusual bone formation or potential space occupying lesions that lead to nerve problems, MRI gives the most informative test results.

   Bear in mind the increased sensitivity of MRI. A radiologist who has not had the necessary patient contact may incorrectly read the MRI. Therefore, it is important to read the films yourself and not just rely on the report.

   Furthermore, it is important to use a service that will provide very close cuts and multiple sequences in multiple planes for the most detailed information. This will allow you to pick up on subtle alterations as well as simple problems that you may not have uncovered during the clinical exam.

Key Insights On Testing For Nerve Problems

   Nerve compression about the heel is one of the most difficult problems to detect and is the cause of multiple cases of missed diagnosis. Often, multiple doctors will have treated a calcaneal nerve compression or tarsal tunnel without improvement prior to the patient presenting to our institute. When it comes to nerve problems, the biggest issue seems to be the lack of adequate diagnostic testing parameters.

   In our offices, we have set up a simple yet effective protocol for potential nerve problems. After performing a comprehensive clinical exam, we emphasize conservative protection in a brace to prevent stress on the arch and the medial heel nerves.

   We also initiate physical therapy to calm the nerves. As I noted earlier, patients have often seen multiple doctors prior to seeing us and have tried bracing and therapy.

   For patients who are not improving or have failed conservative care and who have suspected nerve problems, we will use the Pressure Specified Sensory Device (PSSD). This device offers a very simple concept of computerized one- and two-point sensory testing. It is painless and will pick up low levels of nerve problems in the foot and ankle far earlier than EMG/NCV testing.

   Neurosensory testing will show abnormal two-point pressure in cases of nerve irritation and also show progressive wasting of the nerve and axonal degeneration of the nerve. Granted, the PSSD is purely a neurosensory test. Often, however, there is a noted sensory loss prior to muscle weakness with nerve problems. Therefore, the PSSD testing is an excellent source of early information.

   What neurosensory testing cannot help with is the differentiation of peripheral neuropathy from lower back issues. In order to perform appropriate testing, test the deep peroneal nerve between the first and second toes. Test the tarsal nerve along its medial branch to the great toe. Then test the lateral plantar branch calcaneal nerve at the medial heel. If further information is necessary, one can also test the common peroneal nerve at the lateral fibular head region.

   If all tests are abnormal, one must add systemic nerve problems or lower back issues to the differential diagnosis as well as compression syndrome at multiple locations. If only the affected nerve is abnormal on one leg, further testing is not necessary.

   An EMG/NCV test is an excellent secondary test in cases of nerve problems if you suspect lower back or neuropathy issues. Accordingly, we will perform a PSSD test and, if further information is necessary, proceed to perform an EMG/NCV.

   Patients often complain that EMG/NCV testing is painful and the information is often not conclusive. Accordingly, I believe a neurosensory test is a better first option when there is a high index of suspicion for lower back or neuropathy issues as possible etiologies for heel pain.

In Conclusion

   With proper workup and diagnostic testing, one can systematically break down a difficult problem such as heel pain and diagnose it with little chance of problems.

   Nothing is more important than ensuring a proper history and thorough examination of the patient. If you assume the patient has plantar fasciitis from the minute you walk in the room, you are not likely to change your mind.
Each diagnostic test has positives and negatives. Overall, MRI offers the most detailed information with little chance of missing a problem.

   However, diagnostic ultrasound is a great source for rapid in-office diagnosis of the most common problems. If nerve testing is necessary, consider neurosensory testing as a first line testing measure as it is not painful and often picks up lower levels of problems than EMG/NCV testing.

   Finally, be aggressive with treatment following a proper diagnosis. Not all problems are surgical but most problems improve with aggressive efforts to relieve pain and treat the underlying source of pain.