Evaluation and diagnosis of common causes of hindfoot pain in adults

INTRODUCTION — Foot pain is common among adults and a frequent reason for primary care visits. Nevertheless, as the differential diagnosis for foot pain is broad and exposure to foot-related problems is often limited during medical training, many clinicians (podiatrists being the obvious exception) may not be adequately prepared to assess the patient with foot complaints.

This topic reviews the common causes of hindfoot pain in the adult, including descriptions of important conditions and a discussion of how to reach a diagnosis. An overview of foot pain generally, including more detailed discussions of foot anatomy and biomechanics, and how to conduct a history and examination of the patient with foot complaints, is provided separately. (See "Overview of foot anatomy and biomechanics and assessment of foot pain in adults".)

The evaluation of patients with forefoot and midfoot pain is reviewed separately. (See "Evaluation, diagnosis, and select management of common causes of forefoot pain in adults" and "Evaluation, diagnosis, and select management of common causes of midfoot pain in adults".)

ANATOMY AND BIOMECHANICS — The anatomy and biomechanics of the foot are reviewed separately. Aspects of the hindfoot anatomy of particular clinical relevance are discussed below (figure 1). (See "Foot and ankle pain in the active child or skeletally immature adolescent: Evaluation", section on 'Anatomy' and "Overview of foot anatomy and biomechanics and assessment of foot pain in adults", section on 'Basic foot structure and biomechanics'.)

The calcaneus has a multifaceted structure that allows for bone articulations and soft tissue attachments (figure 2). These locations are relatively common sites for pathology and injury. The lateral facet of the calcaneus articulates with the cuboid. Strong ligaments stabilize this articulation to allow supinated weight bearing and foot strike without displacing the joint. Damage to these ligaments can cause cuboid subluxation or dislocation.

On the superior aspect of the calcaneus, the posterior facet forms the major articulation with the talus and the floor of the subtalar joint. Damage to the ligamentous support of this articulation places greater stress on the subtalar joint, which may develop arthritic change and can sublux from its normal position, thereby contributing to a pronated gait. The anterior and middle (sustentacular) facets form the sustentaculum tali, which articulates with the anterior portion of the talus.

At the inferior aspect of the calcaneus are found the medial and lateral processes of the tuberosity. These form the center of impact for weight bearing and are sometimes the location of contusions and minor fractures. The plantar fascia attaches to the calcaneal tuberosity, and the medial process commonly develops bone spurs or tenderness associated with the condition.

Laterally, a key landmark of the calcaneus is the peroneal tubercle, which serves as a fulcrum for the fibularis (peroneus) brevis tendon, as it turns to attach to the base of the fifth metatarsal, and the fibularis (peroneus) longus tendon, before it moves to the plantar surface of the foot. More distally, the lateral calcaneus has a curved recess known as the sinus tarsi. Synovial structures at the sinus tarsi can become inflamed from abnormal gait.

The insertion of the Achilles tendon is found at the posterior calcaneus. Excessive traction at the insertion over time can cause bony hypertrophy or even an exostosis known as a Haglund deformity.

The sustentaculum tali is a "shelf-like" bony prominence and important landmark along the medial calcaneus. Superiorly, the calcaneonavicular, medial deltoid, and medial talocalcaneal ligaments attach at this site. Just beneath the sustentaculum, a shallow groove contains the flexor hallucis tendon. This is a potential site of impingement in dancers and other athletes. The sustentaculum tali is also the location for most cases of medial tarsal coalition.

The talus sits within a mortise formed by the medial and lateral malleoli and the distal leg syndesmosis. The talus has multiple facets and serves as the keystone of the articulation between the leg and the foot. The superior facet, which is covered with articular cartilage, articulates with the tibia. The lateral facet articulates with the lateral malleolus. Inferiorly, the posterior facet articulates with the calcaneus, forming the subtalar joint. Anteriorly and medially, the talar head articulates with the navicular. The superior dome of the talus is a frequent site of osteochondral injuries from ankle trauma, particularly ankle sprains. Talar injury can impair blood flow to areas of tenuous circulation, potentially leading to osteonecrosis [1].

EPIDEMIOLOGY OF LOCALIZED HINDFOOT PAIN — Foot pain affects 19 percent of males and 25 percent of females based on data from the Framingham foot study [2]. Women are affected more often than men. With advancing age, pain often limits patient mobility. Foot pain develops most often in the forefoot, followed by the midfoot and arch, while pain in the hindfoot is least common. According to a meta-analysis of 31 population-based studies (including 75,505 participants) of the epidemiology of foot pain, the prevalence of hindfoot pain among patients 45 and older ranges from 4 to 20 percent [3].

Hindfoot pain can occur in the region of the anterior, medial, and lateral ankle as well as the heel and proximal aspect of the plantar region. Plantar heel pain is a common reason for medical visits, and its prevalence increases with age [4]. Heel pain accounts for 11 to 15 percent of all visits to foot and ankle surgeons, while plantar fasciitis accounts for over one million outpatient visits per year in the United States. Estimates are that 10 percent of all adults will develop plantar fasciitis at some time. (See "Plantar fasciitis".)

Many factors are associated with hindfoot and heel pain. Pronated foot strike is associated with a higher rates of heel pain in men and women, whereas a supinated foot strike is associated with lower rates among women [5]. Greater shoe wear, prolonged standing on hard surfaces, sports activity, and a higher body mass index are among the many variables implicated in the development of rear foot pain in one or more studies.

HISTORY AND EXAMINATION — The history and examination of patients complaining of foot pain are reviewed in detail separately. Aspects of particular relevance to hindfoot pain are discussed below (figure 1). (See "Overview of foot anatomy and biomechanics and assessment of foot pain in adults", section on 'Anatomy and biomechanics' and "Overview of foot anatomy and biomechanics and assessment of foot pain in adults", section on 'Anatomy-based approach to diagnosis'.)

When obtaining a history to determine the most likely causes of hindfoot pain, the following questions are often useful:

●"Was the onset of your hindfoot pain sudden or gradual?"

Gradual pain develops from osteoarthritis (OA) of the subtalar or true ankle (tibiotalar) joint and other chronic conditions listed below. An abrupt onset of pain raises the possibility of stress fracture, tendon or fascial tear, calcaneal tuberosity contusion, and other acute or acute-on-chronic injuries.

●"Does your pain localize over the posterior aspect of the heel?"

Pain at this location suggests injury to the distal Achilles tendon or tendon insertion, or a Haglund deformity.

●"Does your pain primarily involve the plantar surface of the hindfoot?"

Plantar fasciitis and calcaneus contusion are the most common causes of plantar hindfoot pain.

●"Is the pain in the plantar heel accompanied by burning pain or tingling that radiates to the plantar forefoot?"

This pain pattern is most consistent with tarsal tunnel syndrome. In most cases, such pain occurs only with weight bearing.

●"Did the heel pain follow distance running or another intense sports activity?"

This suggests the possibility of stress fracture or possibly acute tendon injury.

●"Is the pain in the heel accompanied by systemic symptoms, or do you have a history of chronic disease?"

Medical conditions, including a number of rheumatologic diseases, can cause hindfoot pain. However, these cases are relatively uncommon compared with other causes, and often, diagnosis of any rheumatologic condition has been established.

Examination begins with visual inspection, including a systematic examination of foot structure and position, followed by palpation and special maneuvers. Notable findings to observe include the following:

●Position of the calcaneus while standing. Is there a varus or valgus (picture 1) shift?

●Redness or other skin changes.

●Swelling along any portion of the hindfoot. Does swelling localize to the area anterior and inferior to the lateral malleolus?

●Appearance of the sinus tarsi.

●Longitudinal arch (figure 3) type: cavus (high arch (picture 2)), neutral, or planus (flatfoot (picture 3)).

●Notable thickening of the Achilles tendon or any bony abnormality. Comparing feet may be useful.

●Walking and running gait as appropriate. (See "Clinical assessment of walking and running gait".)

Palpation of key anatomical structures guides diagnosis. Anatomical structures to palpate include:

●Insertion of the plantar fascia particularly at the medial calcaneus (picture 4 and figure 4).

●Calcaneal tuberosity on plantar surface.

●Calcaneus bony contour lateral, medial, and posterior.

●Achilles tendon and insertion onto calcaneus (picture 5).

●Medial and lateral ankle tendons, particularly as they pass around respective malleoli (figure 5 and picture 6).

With inversion and eversion of the ankle, the medial and lateral corners of the talus become more prominent, respectively, and easier to palpate and determine the presence of focal tenderness.

Motion around the hindfoot occurs at the ankle (tibiotalar) and subtalar (talocalcaneal) joints. Assess ankle plantar and dorsiflexion, and eversion and inversion. Diminished motion compared with the opposite ankle and foot raises suspicion for impingement. The clinician assesses subtalar joint motion by stabilizing the talus and ankle in neutral position and then passively everting (valgus stress) and inverting (varus stress) the calcaneus. Normal eversion is about 5 degrees; normal inversion is about 20 degrees.

During gait, eversion is commonly referred to as pronation, while inversion is commonly referred to as supination. In normal locomotion, the hindfoot functions best with a minimum of 4 to 6 degrees of both supination and pronation. Supination usually exceeds pronation by a 2:1 ratio [6]. With plantar flexion, the inversion and eversion angles of the foot on the talus increase.

DIAGNOSTIC APPROACH TO HINDFOOT PAIN — Assessment of hindfoot pain begins with obtaining a history. The first step is to determine the time course and the mechanism of any injury. Likely mechanisms include acute trauma, chronic overuse, or any recent intense or substantial increase in activity. When no mechanism appears obvious, more extensive questioning about systemic symptoms suggesting chronic disease follows. In some cases, a diagnosis (eg, rheumatoid arthritis, spondyloarthropathy) may be known. Once the mechanism and time course have been clarified, the most likely causes are considered based upon this history and the primary location of discomfort: plantar heel, lateral hindfoot, medial hindfoot, or posterior heel. Important questions to ask and key clinical findings when assessing hindfoot pain are summarized in the following table (table 1).

Pain at two anatomic structures of the rear foot account for the majority of visits for hindfoot pain to primary care and sports medicine clinicians: the plantar fascia and the distal portion of the Achilles tendon, including the insertion. Characteristic history and examination findings confirm most cases of plantar fasciitis and Achilles tendinopathy. (See "Plantar fasciitis" and "Achilles tendinopathy and tendon rupture".)

For plantar heel pain, plantar fasciitis is the presumptive diagnosis. Nearly all patients with plantar fasciitis have some degree of medial-sided plantar heel pain when they first step out of bed in the morning or when they get up to walk after sitting for a time. Plantar fasciitis pain should resolve at night or when the individual is not weight bearing. Examination reveals significant tenderness at the insertion of the plantar fascia (picture 4), most commonly along the medial aspect of the heel, although in a few cases, tenderness is focused at the center of the plantar heel. If tenderness is greatest at the lateral heel, the clinician should entertain alternative diagnoses, such as a lateral calcaneal tuberosity contusion or stress fracture.

When pain and tenderness are absent at the plantar fascia insertion of a patient originally thought to have plantar fasciitis, contusion of the medial calcaneal tuberosity may be present. Pressure over the calcaneus in the midheel may indicate a contusion. For those who have access to ultrasound, confirmation of the diagnosis of plantar fasciitis can be made quickly with a long-axis scan looking at the appearance and thickness of the plantar membrane (image 1). (See "Musculoskeletal ultrasound of the ankle and hindfoot".)

The other common area of hindfoot pain is the distal Achilles tendon from approximately 6 cm proximal to its insertion at the calcaneus to the insertion itself (picture 5). Typically, patients with Achilles tendinopathy give a history of extensive running, jumping, or comparable activity. Achilles pain unrelated to such activity should prompt the clinician to explore the possibility of rheumatologic disease, other chronic diseases, and recent use of quinolone antibiotics. Palpation of the tendon from side to side and anterior to posterior begins at the insertion and proceeds proximally. An area of pathology is often found 2 to 6 cm superior to the calcaneus, and if tendinopathy is present, typically reveals warmth, tenderness, thickness compared with the uninvolved (presumably normal) heel, and sometimes swelling. For those with access to point-of-care ultrasound, longitudinal and transverse scans of the tendon can confirm the diagnosis of tendinopathy or raise the possibility of alternative diagnoses by revealing abnormalities at the tendon insertion, calcifications, or retro-calcaneal bursitis. (See "Musculoskeletal ultrasound of the ankle and hindfoot", section on 'Posterior ankle region'.)

Pain at the area of the Achilles tendon insertion may be caused by a Haglund deformity, enthesopathy, or bursitis. A Haglund deformity has a characteristic appearance (picture 7). If such deformity is absent, palpate for the presence of enthesopathy or bursitis. Tenderness from enthesopathy may include the superior calcaneus as well as the tendon. Discreet swelling commonly occurs. When the tendon itself appears nontender, squeeze the space deep to the distal tendon and anterior to the posterior talus where the bursa is located. Focal tenderness suggests bursitis.

For the individual with medial hindfoot pain related to high-energy trauma, the medial malleolus, medial talar dome, and calcaneus are likely sites of injury and should be assessed. Following physical examination, ultrasound is useful for the initial evaluation, but when a fracture appears likely, plain radiographs are needed. When vigorous sport or overuse seems the likely cause, assessment of the posterior tibialis and flexor hallucis tendons is warranted. In ballet dancers, flexor hallucis tendinopathy is an important consideration. Each of these tendons can be assessed with diagnostic ultrasound. Neurogenic pain radiating from the medial hindfoot to the forefoot suggests tarsal tunnel compression. Examination should include testing for a Tinel sign and assessing stance and gait for significant pronation. (See "Ankle fractures in adults" and "Non-Achilles ankle tendinopathy" and "Musculoskeletal ultrasound of the ankle and hindfoot".)

Lateral hindfoot pain related to trauma calls for assessment of the lateral malleolus, lateral corner of the talar dome, and the calcaneus. When vigorous activity or overuse seems the likely cause, the peroneal tendons should be assessed. Suggestive findings include local warmth, swelling around the tendons posterior and inferior to the lateral malleolus, pain elicited by resisted foot eversion, and possibly subluxation or displacement of the tendons over the lateral malleolus. Swelling may localize to the sinus tarsi and, if so, stance and gait often reveal excess pronation or supination that stresses the lateral ankle. In a pronated foot with sinus tarsi swelling, examination may demonstrate that the subtalar joint has lost normal motion.

In patients with hindfoot pain not associated with injury or overuse, clinicians should consider medical conditions as the source of pain. A good history is the key to assessing such medical conditions. Systemic symptoms such as fever or chills, weight loss, prolonged morning stiffness, swelling or pain in other joints, prior history of cancer, long-standing chronic disease, history of sickle cell anemia, and neuropathy are all historical "red flags" that hindfoot pain may relate to a medical condition. (See 'Medical conditions that can cause hindfoot pain' below.)

COMMON CAUSES OF HINDFOOT PAIN — A table summarizing diagnostic considerations in the patient with hindfoot pain is provided (table 1). For ease of use, the discussion below of individual conditions is organized into four categories: chronic, acute, traumatic, and medical. However, in some cases, a condition may fall into two or more of these categories.

Chronic conditions of the hindfoot

Plantar fasciitis — The deep plantar fascia (plantar aponeurosis) is a thick, pearly-white tissue with longitudinal fibers intimately attached to the skin (figure 4). The central portion is thickest and attaches to the medial process of the tuberosity of the calcaneus. Plantar fasciitis is among the most common causes of rear foot and heel pain. Plantar fasciitis is discussed in detail separately; clinical information that is important for diagnosis is summarized below. (See "Plantar fasciitis".)

The plantar fascia merges distally with the capsule of the metatarsophalangeal (MTP) joints. Therefore, during first MTP extension (eg, during the step-off phase of gait), the fascia tightens and pulls on its proximal attachment. Thus, conditions such as hallux limitus [7] or bunions (hallux valgus) that diminish the flexibility and motion of the first MTP can strain the plantar fascia, making fasciitis more likely. Anatomic conditions that stress the insertion of the plantar fascia at the medial calcaneus, such as a high cavus foot or pes planus with a pronated foot, may also contribute. Nonanatomic factors that may predispose to plantar fasciitis include excessive weight, significant acute weight gain, prolonged standing (particularly on hard surfaces), and inadequate shoe support.

Most patients with plantar fasciitis describe intense pain when they first step out of bed in the morning. Pain typically occurs at the medial insertion of the plantar fascia into the calcaneus. This corner of the plantar fascia is thought to undergo greater torque during gait than other areas. Pain is most severe when patients begin walking or running but gradually subsides with activity. Dull pain often persists throughout the day but generally subsides with sitting, only to increase again with standing or walking. Night pain is not typical of plantar fasciitis, and its presence suggests the need for additional diagnostic testing looking for a calcaneal stress fracture. (See "Calcaneus fractures", section on 'Stress fractures'.)

Examination findings typically include tenderness at the medial insertion of the plantar fascia into the calcaneus. Tenderness is best elicited by the examiner dorsiflexing the patient's toes with one hand in order to pull the plantar fascia taut and then palpating with the thumb or index finger of the other hand along the fascia from the heel to the forefoot (picture 4). The plantar fascia wraps around the calcaneus in many patients, so pain patterns can vary. Rarely, localized swelling near the fascial insertion may be noted.

Patients with a thin heel pad and those who have sustained local trauma may have pain directly over the prominence of the calcaneal tuberosity (a "march" or "stone" bruise) that can mimic plantar fasciitis. Ultrasound imaging can demonstrate some changes associated with plantar fasciitis, including fascial thickening (image 1), nodules, and partial or complete tears.

Tarsal tunnel syndrome — The tarsal tunnel is a bony canal that runs below the medial malleolus and through which travel the posterior tibialis, flexor hallucis, and flexor digitorum tendons, posterior tibial artery and vein, and tibial nerve (figure 6 and figure 7). Arthritic change, a bone spur off the medial malleolus, or some other lesion may reduce the space within the tarsal tunnel and compress the structures contained within it.

Tarsal tunnel syndrome often affects individuals with a prior injury to the medial ankle or a markedly pronated gait. When the arch of the foot collapses and the foot pronates excessively, the bones of the tibiotalar or subtalar joint may move and even sublux, and this too can cause compression of the structures running through the tarsal tunnel. Pressure on the tibial nerve causes neuropathic pain that typically radiates to the plantar surface of the forefoot. However, the branching pattern of the medial and lateral plantar nerves and the medial calcaneal nerve can vary, and compression of these branches may cause pain in the heel or other areas of the foot [8]. Over time, compression of the tarsal tunnel can also result in injury of the posterior tibialis or flexor hallucis tendons.

Patients with tarsal tunnel syndrome typically present with aching, burning, numbness, and tingling involving the sole of the foot, the distal foot, the toes, and occasionally the heel. The pain may radiate proximally to the calf or higher. The discomfort is often most irritating at night, may be worse after standing, and sometimes leads to the desire to remove the shoes, even while driving. The physical examination may be normal in patients with tarsal tunnel syndrome of relatively recent onset. When present, important findings include swelling below and posterior to the medial malleolus. A prominent Tinel sign may be present over the nerve posterior to the medial malleolus, and there may be sensory loss over the plantar surface of the foot, but not extending onto the dorsum.

A markedly pronated foot, significant calcaneal valgus (picture 1), or failure of the rear foot to invert during heel raise is a clue that the patient is at risk for tarsal tunnel syndrome or medial flexor tendon injury. Ultrasound imaging may demonstrate swelling or anatomical changes in the tarsal tunnel (image 2). Diagnosis and management of these conditions are reviewed in detail separately. (See "Overview of lower extremity peripheral nerve syndromes", section on 'Tarsal tunnel syndrome' and "Non-Achilles ankle tendinopathy", section on 'Medial ankle tendinopathy' and "Musculoskeletal ultrasound of the ankle and hindfoot", section on 'Medial ankle region'.)

Achilles tendon insertion and Haglund deformity — Many patients develop pain around the insertion of the Achilles tendon into the calcaneus (figure 8). Most often, such pain stems from injury to the distal Achilles tendon (tendinopathy or enthesopathy) or a Haglund deformity (picture 7), an exostosis that develops at the superior aspect of the posterior calcaneal tuberosity. Both conditions are most likely to develop and become painful in distance runners and athletes involved in running and jumping sports. They may also affect individuals who do a lot of walking, hiking, or stair climbing. Tenderness is located at the insertion of the Achilles tendon or directly over the exostosis with a Haglund deformity. The clinician may note thickening at the Achilles tendon, local redness and swelling, and the prominent bump on the upper posterior calcaneus that is characteristic of the Haglund deformity. The clinical significance of Haglund deformity is questionable, and surgical removal offers inconsistent benefit [9]. The diagnosis and management of classic midportion Achilles tendinopathy is reviewed separately, but insertional Achilles tendinopathy (ie, enthesopathy) is a distinct entity and is reviewed below. (See "Achilles tendinopathy and tendon rupture".)

Insertional Achilles tendinopathy involves Sharpey's tendon fibers that pull free from their insertion on the boney periosteum of the calcaneus [9]. This causes an inflammatory response and may lead to calcification at the tendon insertion or formation of a bony exostosis [10]. Insertional Achilles tendinopathy accounts for 20 to 25 percent of Achilles problems. Certain subgroups have greater risk, and this includes running athletes, who account for 53 percent of cases. Among higher-level runners, the injury affects 7 to 9 percent of competitors annually. Men are at greater risk and affected in up to 89 percent of sports-related cases. Achilles tendinopathy risk increases with age, and up to 75 percent of enthesopathy cases occur in older athletes [11]. Some reports suggest that calcaneal varus malalignment is present in 60 percent of cases [11,12].

On examination, the presence of a Haglund deformity suggests relatively high stress at the Achilles insertion. Local warmth, erythema, swelling, tendon thickness, and focal tenderness of the tendon suggest that pain arises from tendinopathy rather than the Haglund deformity (picture 5). If retrocalcaneal bursitis is the source of pain, squeezing the soft tissue behind the Achilles tendon and just above the superior border of the calcaneus is likely to be painful, while direct palpation of the tendon will not elicit pain. Both the tendon and bursae are easily seen on ultrasound, which can help to identify Achilles pathology. In complex cases that require a definitive diagnosis, magnetic resonance imaging (MRI) may provide additional information.

Insertional tendinopathy responds to standard rehabilitation using concentric exercises for Achilles problems, but unlike classic tendinopathy, the benefit of eccentric exercises is less clear. For patients with insertional tendinopathy, eccentric exercise must be added more gradually and only after good progress is made with a concentric exercise program. Even with proper rehabilitation, 3 to 12 months may be needed before ankle plantar flexion strength approaches normal levels [13]. High-quality evidence for other treatments is limited, but icing, heel lifts, and compressive straps are often used. Sports insoles and orthotics are used to correct for foot pronation or other alignment issues.

The results of small randomized trials suggest that topical nitroglycerin relieves symptoms in patients with Achilles tendinopathy [14,15]. While such studies have not focused on insertional tendinopathy, the author has treated and followed hundreds of cases and found the clinical response to be similar in both noninsertional and insertional Achilles tendinopathies. Topical and oral nonsteroidal antiinflammatory drugs (NSAIDs) may reduce pain but add few, if any, benefits beyond standard rehabilitation. Small trials suggest that extracorporal shock wave lithotripsy, along with eccentric rehabilitation, leads to faster resolution than rehabilitation alone [16]. Studies of other treatments, including injections with glucocorticoids, polidocanol, autologous blood, platelet-rich plasma, and aprotinin, are inconclusive.

For insertional tendinopathy that persists despite appropriate conservative care, various surgical approaches have been used [9]. Tendoscopy, open and percutaneous tenotomy, tendon debridement and reattachment, and resection of Haglund deformity with repositioning of the tendon are among the available options. Clinical outcome studies report improvements in pain and functional assessment scores, but rates of return to high-level sport vary. Complication rates for surgical interventions average approximately 11 percent, with infection as the primary problem.

Sinus tarsi syndrome — The sinus tarsi, or talocalcaneal sulcus, sits anterior and inferior to the lateral malleolus and is the space between the medial neck of the talus and the superior aspect of the anterior calcaneus. This limited area is bounded by several ligaments and contains tendons, synovium, adipose tissue, and neurovascular structures. Sinus tarsi syndrome appears to be caused by stress at the lateral ankle, often involving excessive pronation due to subtalar joint instability [17,18]. As the foot pronates, the lateral calcaneus and cuboid rotate, resulting in compression of the soft tissues in the sinus tarsi against the lateral calcaneus. The end result is that the compressed tissues become inflamed and swollen.

Patients may note puffiness or swelling at the sinus tarsi (picture 8). Usually there is little discomfort, but at times, the area becomes painful and possibly reddened. While in younger individuals the condition may be an acute or subacute syndrome associated with lateral ankle injury, in adults it is more often chronic. The examiner may note a significantly pronated foot with calcaneal valgus. When the patient walks, the foot pronates and the ankle often translates horizontally so that the lateral foot no longer contacts the ground. Palpation reveals soft tissue swelling and, at times, pain with deep palpation. Ankle motion is usually normal but sometimes shows excessive eversion. Ankle ligaments most often are stable, but when the lateral ankle ligaments manifest laxity, this probably has contributed to the development of the subtalar joint instability. (See "Ankle pain in the active child or skeletally immature adolescent: Overview of causes".)

Imaging rarely helps to confirm the diagnosis, although anteroposterior (AP) and lateral plain radiographs of the ankle and foot may show some signs of osteoarthritis. Ultrasound shows some soft tissue swelling noted by hypoechoic change in the sinus tarsi and some degree of increased Doppler activity. MRI, when compared with arthroscopy, fails to reveal the injury causing sinus tarsi syndrome in approximately 40 percent of cases [19].

Treatment focuses on ankle compression to reduce swelling and either arch supports or custom orthotics that eliminate pronation and normalize foot position while standing and during gait. Appropriate shoes may assist resolution, as women wearing heels have greater ankle motion, which causes additional swelling in the sinus tarsi. Shoes worn without added arch supports or custom orthotics need good built-in arch supports. In recalcitrant cases of sinus tarsi syndrome, arthroscopic treatment often results in improvement in both pain and function. In one series, 88 percent of patients demonstrated tears of the interosseous talocalcaneal ligament and 55 percent demonstrated synovitis at arthroscopy [20].

Piezogenic papules — Piezogenic papules are small, yellowish nodules noted around the heel capsule (picture 9 and picture 10). They result from minor herniations of the fat pad through the capsule of connective tissue that surrounds the calcaneus. Typically, the papules are asymptomatic, but clinicians can easily identify them by appearance alone. Piezogenic papules have no known clinical significance but may represent indirect evidence of an excessively hard heel strike during gait. They are also a characteristic skin finding in Ehlers-Danlos syndrome. (See "Clinical assessment of walking and running gait" and "Clinical manifestations and diagnosis of Ehlers-Danlos syndromes".)

Subtalar arthritis — Subtalar arthritis falls into one of three categories:

●Chronic nontraumatic

●Post-traumatic

●Medical condition related

Primary arthritis caused by a chronic, nontraumatic condition may relate to anatomic malalignment, causing excessive supination or pronation. Leg-length inequality may also increase the forces sustained by the subtalar joint, producing chronic degeneration. Secondary arthritis from trauma may follow ankle fractures, calcaneal or talar fractures, and true ankle joint arthritis (tibiotalar joint). Arthritis of the tibiotalar joint causes greater forces to be exerted on the subtalar joint, increasing the risk of subsequent subtalar arthritis. Systemic rheumatologic disease often affects the subtalar joint. In an observational study of spondyloarthropathy, 22 of 60 subjects developed hindfoot arthritis [21]. When spondyloarthritis affects the foot, the hindfoot is most commonly affected.

Overuse tendon conditions

Fibularis (peroneal) tendon injury — Patients with lateral foot pain posterior to the malleolus who are active but do not recall an ankle sprain or other specific trauma often have peroneal tendinopathy. They complain of pain with running, abrupt change of direction (cutting), or jumping that worsens with continued activity. Runners experience this injury from excessive running on banked or uneven surfaces. Shoes with extreme lateral wear place additional stress on the peroneal tendons and may be a contributing factor. Suggestive clinical findings include swelling posterior and distal to the lateral malleolus or, less often, at the base of the fifth metatarsal. In many patients, the foot may be excessively supinated, and observation from the rear demonstrates calcaneal varus. Tenderness is usually noted just posterior to the lateral malleolus and may be present along the course of the tendons distally. Pain is often reproducible with resisted active dorsiflexion and eversion of the ankle. Peroneal tendon injury is discussed in greater detail separately. (See "Non-Achilles ankle tendinopathy", section on 'Lateral ankle tendinopathy'.)

Posterior tibial tendinopathy — The posterior tibialis muscle provides power for the push-off phase of running and jumping. Intense physical or sporting activity involving these movements may place excessive strain on the tendon, leading to injury. Patients with posterior tibialis tendinopathy typically complain of pain around the posteromedial ankle. Swelling may be present along the course of the tendon. When asked to perform heel raises, the patient typically experiences difficulty or inability to perform the movement, or sensations of weakness or pain inferior or posterior to the medial malleolus. Overuse and recurrent injury can result in this becoming a chronic tendinopathy.

With severe tendinopathy or tendon tear or avulsion, swelling and pain extend into the midfoot, and the longitudinal arch may drop, resulting in a "flat foot" (pes planus). (See "Non-Achilles ankle tendinopathy", section on 'Medial ankle tendinopathy' and "Evaluation, diagnosis, and select management of common causes of midfoot pain in adults", section on 'Peroneal (fibularis) brevis, longus, and posterior tibial tendinopathy'.)

Flexor hallucis tendinopathy — The terminal phase of push-off requires powerful contraction of the flexor hallucis muscle, producing great toe flexion. Injury to the flexor hallucis tendon occurs during activities that entail excessive stress during toe-off. Ballet dancers sustain this tendon injury with some frequency. Clinical findings include pain located posterior to the medial malleolus deep in the medial heel and increased pain with resisted great toe flexion, performed with the patient's foot held in plantar flexion. With severe tendinopathy or tendon tears, swelling and pain may extend into the midfoot. (See "Non-Achilles ankle tendinopathy", section on 'Medial ankle tendinopathy'.)

Acute Achilles tendinopathy — After sprinting, running hills, or doing excessive jumping, the Achilles tendon may become inflamed. The typical location of pain and tenderness is the posterior heel, about 2 to 4 cm proximal to the insertion of the Achilles onto the calcaneus. (See "Achilles tendinopathy and tendon rupture".)

Traumatic conditions

Anterior and posterior ankle impingement — The anterior and posterior aspects of the ankle (specifically the tibiotalar) articulation are the site of pain for a number of conditions.

Spurring off the anterior distal tibia or the anterior superior talus can produce impingement at the anterior ankle, causing pain around the proximal talus. Such pain can also occur without spurring. In either situation, sports or other activities that cause repeated stressful dorsiflexion of the foot may contribute to the injury. Among jumping sports, basketball and volleyball account for numerous cases of anterior impingement. Ballet and, less commonly, other dance disciplines place great stress on the ankle, as can activities like hiking or climbing ladders. Anterior ankle swelling or an abnormal contour of the anterior ankle and tibiotalar articulation may be apparent. Ankle dorsiflexion may be limited, and localized tenderness present. Standard radiographs usually confirm the diagnosis, but sometimes oblique views are needed [22]. (See "Non-Achilles ankle tendinopathy".)

Demi-plié position (knees bent while heels remain on the ground) triggers pain in ballet dancers, who can be asked to assume the position as part of their examination. Other athletes can be asked to squat while keeping their heels on the ground to determine whether ankle dorsiflexion reproduces characteristic pain. While patients perform such maneuvers, the examiner can look for motion restrictions or asymmetries (eg, inability to perform maneuver on one side). Deep palpation of the space deep to the distal Achilles tendon may sometimes elicit pain, but often no abnormalities are noted during a static examination, which emphasizes the importance of performing a dynamic examination.

Posterior ankle impingement arises from bone spurs off the posterior talus or os trigone, an accessory bone. Such impingement causes pain deep to the Achilles tendon in the posterior hind foot. Repeated or stressful plantar flexion often triggers this condition. Dancing on pointe and relevé places ballet dancers at high risk, and athletes involved in sprinting or jumping sports can develop the condition as well. (See "Ankle pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Os trigonum syndrome (posterior ankle impingement)'.)

The lateral corner or, less frequently, the medial corner of the talus may sublux anteriorly in individuals who have sustained multiple ankle sprains, creating an incompetent ligamentous capsule around the talus. For many individuals, this condition creates some abnormal rotation of the foot, and the talus will appear more prominently on the lateral (or medial) aspect, which projects out of the mortise. When the lateral corner of the talus is affected, the athlete often demonstrates supination and slight internal rotation of the foot. If the medial corner is affected, this leads to pronation and often external rotation of the foot. An unstable talar position contributes to increased stress on the lateral or medial foot. Pain and swelling may develop, usually in the sinus tarsi laterally or the medial arch and tarsal tunnel medially.

To manage this injury, clinicians often need to provide the patient with ankle support in addition to foot pads, a sports insole, or a custom foot orthotic to restore normal foot and ankle alignment. Treating the foot pain without addressing the underlying ankle problem is rarely adequate. Ankle sprains and chronic instability are associated with an increased risk of talar dome fractures and osteochondritis (OCD) of the talus. (See "Talus fractures" and "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Talus'.)

Heel contusion — Contusion of the heel, sometimes referred to as a heel pad or foot pad contusion, can be caused by acute trauma (eg, landing from high fall), stepping on a root or rock during trail running, or chronic overuse (eg, distance running in shoes with inadequate heel cushion). Examination reveals focal soft tissue tenderness at the plantar surface of the midportion of the heel (not at the insertion of plantar fascia, which suggests plantar fasciitis). This is where the calcaneus is most prominent and thus at higher risk of contusion.

Most injuries are minor and involve breakdown of the protective fat pad. The fat pad has fibrous septae that act as coil-like shock absorbers during heel strike. These septae enclose the fat cells and hold them in position to provide cushion. When the septae split, the calcaneus may have less protection centered under the weightbearing surface, which leads to contusion and pain with impact. (See "Heel pain in the active child or skeletally immature adolescent: Overview of causes".)

Most injuries are readily managed with standard treatment consisting of rest, ice, support (including a heel pad and possibly taping (picture 11)), and over-the-counter analgesics as needed. Sometimes, a donut-shaped pad at the heel reduces impact at the calcaneus and causes less disruption than a full heel pad. A period of non-weight bearing may be needed if pain is severe. More severe pain that does not resolve within five to seven days of appropriate treatment should prompt imaging. When standard heel radiographs are normal, MRI can exclude more serious conditions, such as calcaneal bone contusions with edema or a calcaneal stress fracture [23].

As the patient resumes activity, footwear should be checked to determine if heel cushioning is adequate. In some situations, prolonged use of heel pads, soft heel cups, or even a cushioned orthotic may speed return. Activity may be resumed once the patient can run without a limp or too much pain. Activity can be increased steadily once symptoms subside. (See "Calcaneus fractures".)

Calcaneal and talar stress fractures — Stress fractures of the calcaneus occur infrequently. Typically, these present as persistent heel pain that continues to cause discomfort at night. The patient often relates a history of high-intensity activity, usually running but sometimes hiking or other sports. These fractures generally heal well with conservative treatment. (See "Calcaneus fractures", section on 'Stress fractures'.)

Stress fractures of the talus are rare but at relatively high risk for nonunion. Most reports describe these fractures in long-distance runners. Deep anterior ankle pain and diffuse aching in the rear foot are common symptoms. When a talar stress fracture is suspected, diagnosis is made by MRI. (See "Overview of stress fractures".)

Traumatic fractures of talus and calcaneus are discussed separately. (See "Talus fractures" and "Calcaneus fractures".)

Medical conditions that can cause hindfoot pain

Rheumatologic diseases

●Rheumatoid arthritis — Patients with rheumatoid arthritis often develop diffuse foot pain early in their disease (picture 12). The odds ratio for a rheumatoid patient to have hindfoot pain is over 10 times that of controls [24]. (See "Clinical manifestations of rheumatoid arthritis", section on 'Lower extremity'.)

●Spondyloarthropathy and ankylosing spondylitis — Both of these conditions cause enthesopathies that often affect the Achilles tendon. Heel pain arises from tendinopathy and retrocalcaneal bursitis. Small studies report a good response to glucocorticoid injection under ultrasound guidance [25]. (See "Clinical manifestations and diagnosis of peripheral spondyloarthritis in adults".)

●Psoriatic arthritis — Psoriatic arthritis causes a number of changes at the heel. These include erosion of the calcaneus superior to the Achilles insertion and bone spurs at both the Achilles and plantar fascia insertion. Enthesopathy and retro-calcaneal bursitis are common in other seronegative forms of arthritis. In a retrospective study, 14 of 26 patients with psoriatic arthritis had inflammatory heel pain [26,27]. (See "Clinical manifestations and diagnosis of psoriatic arthritis".)

●Sarcoidosis — Early in this disease, patients often develop unilateral or bilateral heel pain. In a series of seven patients, all had heel pain. Radiologic changes can occur in a variety of patterns [26]. More advanced sarcoid can affect the bones and joints of the hindfoot. (See "Sarcoidosis of bone" and "Sarcoid arthropathy".)

Paget disease — Bony sclerosis and trabecular thickening result in an abnormal bone that may undergo pathologic fracture [28]. Case reports document occurrence in the calcaneus. In one series of 100 patients, 20 had radiographic sclerosis in the calcaneus but only two manifested pain. (See "Clinical manifestations and diagnosis of Paget disease of bone".)

Osteomyelitis of calcaneus — While osteomyelitis of the calcaneus accounts for 1.5 to 10 percent of cases of hematogenous osteomyelitis in children, the condition is rare in adults. Persistent heel pain associated with fever and/or positive inflammatory markers raises the possibility of this diagnosis. (See "Nonvertebral osteomyelitis in adults: Clinical manifestations and diagnosis".)

Sickle cell disease — Bone infarcts and avascular necrosis of the calcaneus are uncommon complications of sickle cell disease and rare complications of sickle cell trait [29]. (See "Overview of the clinical manifestations of sickle cell disease".)

Gout — While common at the metatarsophalangeal joint, gout infrequently affects the hindfoot. Cases of heel and ankle pain related to gout often stem from deposits of tophi causing inflammation and impingement. Reports describe these findings in the talus, calcaneus, and os trigone [30,31]. (See "Clinical manifestations and diagnosis of gout".)

Metastatic disease — Foot metastases are rare. In a series of 694 patients with metastatic disease to bone, only 14 arose in the foot [32]. The calcaneus and talus were the locations for 12 of these 14 cancers. Primary tumors that most commonly metastasize to the foot include genitourinary, breast, colorectal, and lung. (See "Epidemiology, clinical presentation, and diagnosis of bone metastasis in adults".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Plantar fasciitis".)

SUMMARY AND RECOMMENDATIONS

●Epidemiology and mechanisms – Hindfoot pain, particular involving the plantar region, is relatively common among patients 45 and older (figure 1). Pronated foot strike is associated with a higher rate of heel pain. Greater shoe wear, prolonged standing on hard surfaces, sports activity, and a higher body mass index are associated with hindfoot pain. (See 'Epidemiology of localized hindfoot pain' above.)

●History and physical examination – Important elements of the history and examination in patients complaining of foot pain are reviewed separately. Aspects of particular relevance to hindfoot pain are discussed above. (See "Overview of foot anatomy and biomechanics and assessment of foot pain in adults", section on 'Anatomy-based approach to diagnosis' and 'History and examination' above.)

Important hindfoot structures to observe and examine include the following:

•Position of the calcaneus while standing. Is there a varus or valgus (picture 1) shift?

•Swelling along any portion of the hindfoot. Does swelling localize to the area anterior and inferior to the lateral malleolus?

•Appearance of the sinus tarsi.

•Longitudinal arch (figure 3) type: cavus (high arch (picture 2)), neutral, or planus (flatfoot (picture 3)).

•Notable thickening of the Achilles tendon or any bony abnormality. Comparing feet may be useful.

•Insertion of the plantar fascia, particularly at the medial calcaneus (picture 4 and figure 4).

•Calcaneal tuberosity on plantar surface.

•Calcaneus bony contour lateral, medial, and posterior.

•Achilles tendon and insertion onto calcaneus (picture 5).

•Medial and lateral ankle tendons, particularly as they pass around respective malleoli (figure 5 and picture 6).

●Diagnostic approach and common causes – Our suggested diagnostic approach to the patient with hindfoot pain is described above. Important questions to ask and key clinical findings for assessing hindfoot pain are summarized in the following table (table 1). Specific causes of hindfoot pain are summarized in the text. (See 'Diagnostic approach to hindfoot pain' above and 'Common causes of hindfoot pain' above.)