Plantar Heel Pain

Benedict F. DiGiovanni, MD

Michelle L. Prong, BA, MPH

John S. Gould, MD

Dr. DiGiovanni or an immediate family member serves as a board member, owner, officer, or committee member of American Board of Orthopaedic Surgery, Inc. and the American Orthopaedic Foot and Ankle Society. Neither of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Ms. Prong and Dr. Gould.

ABSTRACT

Plantar heel pain affects a vast number of individuals in the general population and can be quite debilitating to everyday functioning. Although plantar fasciitis is the most common etiologic agent of plantar heel pain, other common causes can include plantar fascia rupture, plantar fasciitis with nerve entrapment (tarsal tunnel syndrome), and calcaneal stress fractures. For a typical patient with isolated plantar fasciitis, tissue conditioning and stretching are the preferred first-line treatment with evidence supporting plantar fascia-specific stretching and Achilles/gastrocnemius stretching. Other nonsurgical treatments include the more traditional corticosteroid injection and the more contemporary biologic treatments such as platelet-rich plasma injections. These options have the drawbacks of putting patients at a higher risk for future plantar fascia rupture and being quite expensive, respectively. For chronic persistent symptoms, a number of surgical options exist. Plantar fascia release, typically with nerve entrapment release, is a preferred treatment approach. Successful evaluation and management of plantar heel pain depends upon a thorough history and physical examination, an accurate diagnosis, and an evidence-based treatment approach.

Introduction

Pain on the plantar aspect of the heel is common and has multiple etiologies. Plantar heel pain is distinguished from pain in the posterior heel, as occurs at the Achilles tendon insertion or in the retrocalcaneal space. Plantar fasciitis is the commonly diagnosed condition, but a host of other disorders also can be responsible for a patient’s symptoms.¹ A careful history and physical examination are essential to accurate diagnosis and treatment.

The Diagnosis

It is important to determine the history and circumstances of the onset of symptoms as well as the details of current symptoms. The physical examination requires precise knowledge of the surface anatomy of the foot. Ancillary testing is helpful for documentation and elimination of some of the possible diagnoses but can be misleading in the absence of a careful history and examination.²

The history is useful for determining whether the etiology is mechanical, neurogenic, oncologic, infection based, or traumatic. The possible etiologies are listed in Table 1. The patient may report a remote or recent acute traumatic event. An injury can affect the skin, fat pad, fascia, nerve, vascular system, or bone, or it can introduce a foreign body that causes an infection. The traumatic event is not always related to the disorder, however. Often, an increasingly intense program of walking, running, or weight-bearing activity can strain the plantar tissues, cause repetitive microtrauma, and compress neurologic structures, leading to the spontaneous development of pain.³

The nature of the patient’s current symptoms is useful for determining the responsible anatomic system. It is particularly difficult to sort out a truly mechanical etiology or one that is brought on by activity and appears mechanical but really is not (quasi-mechanical). Nerve pain can be increased with changes in the patient’s positioning or level of activity. The patient should be asked whether the pain begins with the first step in the morning, disappears with further walking, and reappears when arising after sitting; or is the pain made worse by standing or walking? Does the pain occur at night and wake the patient from sleep? It is also helpful to ask the patient to describe the exact location of the pain: Is it in the medial, central, or lateral heel? Does the pain radiate, and, if so, where? Such information should allow the physician to determine the anatomic system or systems involved in the patient’s pain.

Table 1 Etiologies of Plantar Heel Pain

Nerve syndromes (entrapments and neuromas)

Tarsal tunnel syndrome

Tarsal tunnel syndrome with chronic plantar fasciitis

Lateral plantar nerve entrapment

First branch of the lateral plantar nerve involvement (central heel pad syndrome)

Medial plantar nerve entrapment

Calcaneal nerve lesion

Sural nerve lesion

Osteomyelitis of the calcaneus

Plantar fasciitis

Ruptured plantar fascia

Skin lesion or foreign body of the heel pad

Stress fracture of the calcaneus

Tumor of the heel

During the physical examination, the physician locates the precise area of tenderness and often can determine the site of the lesion. The pain may be over the central heel pad, or at the medial soft spot where the neurovascular bundle enters the foot or over the medial tubercle of the calcaneus at the origin of the plantar fascia. Palpation may reveal a subcutaneous foreign body or a lack of prominence of the medial border of the plantar fascia. Dorsiflexion of the ankle and the great toe (the provocative test for a competent plantar fascia) may reveal a structural defect.

The history and physical examination should provide the physician with the information necessary to determine the type of pain, the anatomy involved, and the ideal means of proceeding to a final diagnosis.⁴ The basic ancillary test is the plain radiograph. Any additional imaging is based on the history and physical examination findings. MRI is widely used and quite sensitive, but it is expensive and not particularly specific. Soft-tissue lesions of the heel, such as tumors, foreign bodies, and plantar fascia defects, can be seen with the use of less expensive ultrasonography as well as with MRI. However, the area that can be examined with ultrasonography is more limited, and interpretation of the test results is more difficult than with MRI.

On MRI, a change in signal in the calcaneus is nonspecific and can indicate a stress reaction, stress fracture, osteomyelitis, a bone bruise, or simply plantar fasciitis at the bony origin. If the history suggests infection, blood tests for infection markers should be considered; these should include white blood cell count and differential, erythrocyte sedimentation rate, C-reactive protein level, and labeled white blood cell scan. If a stress fracture is suspected, a healing response with a radiodense area may be noted on lateral radiographs. If further bony information is needed, a CT may be indicated.

Plantar Heel Disorders and Their Treatment

Plantar Fasciitis

Acute proximal plantar fasciitis is a specific entity that involves the origin of the plantar fascia on the medial tubercle of the calcaneus and for convenience is typically referred to as plantar fasciitis. Mid arch pain along the plantar fascia is a distinct and separate disorder and represents strain and inflammation of the mid plantar fascia. Classic plantar fasciitis is an enthesopathy caused by repeated minor trauma to the fascial origin, which lies plantar and superficial to the origin of the flexor digitorum brevis. A broad ledge of bone may extend into this muscle origin, but the bone itself does not cause heel pain, despite the reputation of the so-called heel spur syndrome. This normal variant structure may be incorrectly interpreted as a spur on lateral radiographs of the calcaneus.

Plantar fasciitis typically develops with an increase in activity related to weight bearing or a change in running shoes or other types of shoes. Sometimes the symptoms arise spontaneously, however.⁵ The classic symptoms are pain in the heel during the first step in the morning that disappears after a few steps but may reoccur with standing or walking after sitting. The pain does not occur at night or before arising in the morning. It does not become worse with activity. A variation on this history of the symptoms suggests a different diagnosis, which may involve a progression of plantar fasciitis into another entity.

The physical examination reveals specific tenderness limited to the origin of the plantar fascia, and provocative testing determines that the plantar fascia is intact (Figure 1). The plain radiograph is normal, although the so-called spur may be present. Although MRI is not indicated, it shows reaction in the plantar fascial origin and often in the adjacent bone.

Myriad treatments have been suggested. Some are used indiscriminately for both the acute condition and recalcitrant symptoms that are presumed to represent persistent plantar fasciitis.⁶ Many such treatments appear to be successful because of spontaneous remission, which is common in plantar fasciitis, or because the treatment was administered in combination with tissue-specific plantar fascial stretching, which is the fundamental effective treatment.⁷ It has been hypothesized that because the
Achilles tendon and the plantar fascia are anatomically connected, stretching the Achilles and gastrocnemius will help with symptoms of plantar fasciitis. Indeed, very strong association exists between patients with plantar fasciitis and those with isolated gastrocnemius tightness, suggesting that managing gastrocnemius tightness may be effective at alleviating symptoms of plantar fasciitis.⁸ Although Achilles tendon stretching programs alone may provide some symptom relief, tissue-specific plantar fascia stretching programs in combination with Achilles tendon stretching programs are markedly more effective at improving plantar fasciitis symptoms.⁹^,¹⁰ Furthermore, a tissue-specific plantar fascial stretching program, on its own, has been demonstrated to be more effective in relieving pain symptoms and improving function than an Achilles tendon stretching program alone among patients with chronic plantar fasciitis.⁷^,¹¹ Custom orthoses are not required for most patients, and the use of an over-the-counter orthotic device can provide symptomatic relief by splinting the plantar fascia and gathering the heel pad fat, thereby decreasing the contact of the irritated plantar fascia with the weight-bearing surface.¹² Oral NSAIDs also are helpful for symptom relief.

FIGURE 1 Clinical photograph showing the tender point at the medial tubercle of the calcaneus in plantar fasciitis. (Reproduced with permission from Gould JS: Heel pain syndrome and plantar fasciitis, in Gould JS, Florence MN, eds: The Handbook of Foot and Ankle Surgery: An Intellectual Approach to Complex Problems. New Delhi, India, Jaypee Brothers Medical Publishers, 2013, p 87.)

Various injections have been explored as potential treatments for the symptoms of plantar fasciitis. Corticosteroid injections have been perhaps the most historically widespread of these approaches, contributing to significant improvements in pain symptoms in many studies, with more recent studies comparing efficacy of corticosteroids versus platelet-rich plasma (PRP).¹³^,¹⁴^,¹⁵ However, corticosteroid injections are associated with a markedly increased risk of subsequent plantar fascia rupture and should, therefore, be administered with caution.¹⁶ Corticosteroid injections are also associated with fat pad atrophy and relatively short-term symptom relief. Recent studies have reported that patients’ pain often returns within 3 to 6 months and progresses to their baseline level within 1 year, in comparison with joint mobilization and stretching exercises, which can result in a more permanent resolution of symptoms and improved outcomes at 12 weeks to 1 year and beyond.¹⁴^,¹⁷ In recent years, PRP injections have been optimistically investigated as alternatives to corticosteroid injections. Several studies provide grounds for continued optimism, demonstrating PRP as equally or more effective than corticosteroids at managing symptoms of chronic plantar fasciitis.¹³^,¹⁴^,¹⁵ Furthermore, PRP is associated with long-term symptom relief at 1 year follow-up, by which time many patients receiving corticosteroid injections return to their preinjection symptom severity, and is not known to be associated with the increased risk of plantar fascia rupture of corticosteroids.¹⁴ Other injections currently under study include botulinum toxin and dehydrated human amnion/chorion membrane, both of which have yielded promising preliminary results for the future treatment of plantar fasciitis.¹⁸^,¹⁹

Nonsurgical treatments for plantar fasciitis have been the mainstay of treating the acute condition, with high-level evidence-based studies available to guide appropriate treatment for acute plantar fasciitis.⁹ When these treatments are not sufficient to alleviate symptoms and restore function, surgical approaches may be considered. Yet high-level evidence-based studies for surgical treatment outcomes are limited.⁹ Historically, open surgical release of the plantar fascia has been used to treat persistent symptoms, with or without removal of the so-called heel spur. Heel spur removal is no longer recommended. More contemporary studies including some from the past several years have revealed variable postsurgical outcomes, ranging from symptom relief in nearly three-quarters of patients receiving open or endoscopic plantar fasciotomies on the one hand to persistent pain and further complications on the other.³ Further studies have reported suboptimal outcomes following isolated surgical plantar fascia release including persistent and worsening pain, pain on the lateral border and dorsum of the foot, inability to return to desired activity levels, and classic neurogenic symptoms.⁹^,²⁰^,²¹ In addition, preoperative steroid injections may be associated with patients reporting worse long-term outcomes following an open plantar fascia release.²⁰ The variable postsurgical outcomes combined with the potential for worse outcomes following some standard nonsurgical treatment suggest that the clinical
value of treating plantar fasciitis through an isolated open partial or complete release is uncertain.²⁰ Denervation of the heel, including division of the calcaneal nerves, also has been attempted. Division of only the medial plantar fascia has had variable outcomes. With the advent of endoscopy, partial release of the plantar fascia has been recommended but can lead to complications including laceration of the tibial nerve or vascular structures.²²

Other innovative treatment approaches have been investigated more recently and may be of benefit. The addition of acupuncture was found to add some benefit to a standard protocol using ice, NSAIDs, and stretching.²³ An isolated gastrocnemius contracture has been associated with acute and chronic plantar fasciitis. A 57% incidence of isolated gastrocnemius contracture was found in patients with plantar fasciitis.²⁴ Patients with chronic foot pain, including pain from plantar fasciitis, had a 93% success rate after gastrocnemius recession for an isolated contracture.²⁵ Proximal medial gastrocnemius release for patients with recalcitrant plantar fasciitis and a gastrocnemius contracture led to pain relief in 81% of patients.²⁶ The use of a full-length silicone insole was compared with an ultrasonography-guided steroid injection to the origin of the plantar fascia in 42 randomly chosen patients.²⁷ One month after the procedure, the results were equivalent with respect to heel tenderness and pain relief. Patients who received an injection had less thickness of the fascia. The researchers recommended the use of insoles as primary management. Extracorporeal shock wave therapy (ESWT) is effective at treating recalcitrant plantar fasciitis, with one multicenter randomized clinical trial noting success rate of heel pain reduction at between 50% and 65%.²⁸ In another randomized controlled study of radial extracorporeal shock wave therapy in 245 patients with chronic plantar fasciitis, the success rate was 61%, compared with 42% in those treated with a placebo.²⁹

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