Heel pain is a common foot problem that affects people of all ages and genders. When a person with this condition tries to use the affected heel, it usually causes excruciating pain.
As a result of avoiding placing weight on the affected heel, some people may limp or develop an abnormal walking style.
People with heel pain often describe the pain as worse when they get up in the morning or after they’ve been sitting for long periods. After a few minutes of walking the pain decreases, because walking stretches the fascia. For some people, the pain subsides but returns after (American College of Foot and Ankle Surgeons, 2004)
To be able to effectively treat heel pain, you need to know the root cause. The longer you have heel pain, the more time it will take for it to heal.
The most common causes of heel pain are pain that occurs on the bottom of the heel (plantar fasciitis) and pain that occurs at the back of the heel (Achilles tendinitis).Heel pain is usually mild at first but it can become severe with time.
While mechanical factors are the most common causes, other causes include;
The most common causes for pain on the bottom of the heel are biomechanical abnormalities that lead to pathologic stress of the plantar soft tissues (1-7, pg 329 ACFAS).
Plantar fasciitis, heel spurs, and tarsal tunnel syndrome are some of the causes of pain on the bottom of the heel (Dr. Nicole G. Freels, FACFAOM, 2011.)
According to Podiatry Today, Plantar fasciopathy affects about 10% of the people in America and 1 to 2 million people in America every year.
A consensus is that the majority of patients with heel pain have changes of the plantar fascia.
Those who suffer from chronic pain have more damage. Heel thickening, swelling, and calcification are examples of changes.
Because there are fewer cells and less blood flow to this area of the foot, chronic changes can make healing difficult.
It could be nerve entrapment or a type of tissue that is not healing. New technologies are being tested to see if they can pinpoint the source of the problem.
A heel spur is a calcium deposit causing a bony protrusion on the bottom of the heel bone. (Rick Ansorge, WebMD, 2020, August 28)
Plantar fasciitis is where the thick band of tissue that connects the heel bone(calcaneum) with the rest of the foot (the plantar fascia) becomes damaged and thickened.
Heel spurs are not painful but they can cause heel pain when the plantar fascia is inflamed.
People usually experience pain when they first stand up in the morning or get up after sitting for a long time. When people first begin to walk, they often feel pain in their heels.
The pain may subside after a few minutes, but it will return if people stand for extended periods. The person’s weight can play a role in this.
Other factors, such as tight Achilles tendons and ill-fitting shoes, can worsen the situation.
Questions about pain are important.
A doctor will check the foot and ask about the pain, the amount of walking and standing the patient does, the type of footwear they use, and their medical history.
The doctor will also check for abnormalities in the movement of the joints.
Other physical exams may include
These may be enough to determine a diagnosis, although blood tests or imaging scans may be required in some severe cases.
Initial treatment options focus on relieving pressure on the plantar fascia’s insertion at the calcaneus.
these options include patient-guided stretching exercises of the calf muscles which include;
Other therapies focus on
Usually, there’s an improvement within 6 weeks of initial treatment and the continuation of the therapy session usually heals the pain However, if there’s little or no improvement, the patient should be referred to a podiatrist or foot specialist.
The second phase of treatment includes the continuation of initial treatment plus additional therapy.
It will take about 2- 3 months for 85-90% of patients to respond to treatment in this second phase (26-30), pg 330 ACFAS).
For those who show improvement both in phase 1 and phase 2 therapy should continue the treatment until they are treated.
If no improvement, other systemic diseases should be considered (31-37, pg 330 ACFAS).
During the third phase of treatment, cast immobilization should be added if not already done.
Other treatment options include surgical plantar fasciotomy. Plantar fasciotomy is a surgical procedure that separates your fascia from your heel bone to reduce strain.
Note that in the majority of cases, removal of the plantar heel spur does not treat plantar heel pain (48, 59-61) page 330 ACFAS).
Long-term biomechanical control of excessive pronation through orthotics is important to permanently treat the condition.
There are several fluid-filled sacs behind the heel bone that act as a cushion and a lubricant between muscles and tendons sliding over bone.
They are known as bursa. Repetitive or overuse of the ankle can cause the bursa to become inflamed or irritated leading to heel bursitis.
Symptoms include heel pain, when walking, running, or jumping, or when the area is touched.
The skin around the back of the heel may be red and warm to the touch, and standing on tiptoe may aggravate the pain.
It is most common in people who are just beginning an aggressive exercise routine.
Causes for heel bursitis include:
Treatment measures can include cortisone injections directly into the inflamed bursa, heel padding, orthotics, physical therapy with deep friction massage to break up the bursa, ultrasound +/- phonophoresis with the addition of steroids.
Bruising from rubbing irritation of the capillaries of the heel against the heel counter. This is most commonly seen in runners. Treatment best consists of protective padding and/or injection of the inflamed bursa with cortisone. The asymptomatic bursa can also be removed surgically.
As we mature the fatty tissue layer underneath our heels becomes thinner with less shock absorption for the heel which can lead to pain.
Cushioned insoles, orthotics with accommodation can be helpful
The most common causes of posterior heel pain or pain on the back of the heel are;
The Achilles tendon is the largest tendon (a band of tissue that connects muscle to bone) in the human body and is very strong (Dr. Nicole G. Freels, FACFAOM. (2011))
X-ray scans show spurring or erosions in the tendon. An MRI is the best way to find out the changes inside the tendon.
This condition is common with soccer players or after someone accidentally steps into a hole. The abrupt movement causes partial tears within the tendon which gradually fills with new bone formation.
Initial treatment is aimed at reducing pressure to the area such as heel lifts–for short term treatment–
Other treatment options include;
Local corticosteroid injections are not recommended as they can weaken the tendon and cause rupture. In difficult cases, surgery may be required.
Heel bumps OR Haglund’s Deformity are a bone enlargement on the back of the heel bone. These usually happen to athletes when their shoes rub up against their heels, and they can be made worse by the height or stitches of a shoe’s heel counter.
As a result, the heel suffers from painful bumps or bumps, making exercise extremely difficult.
It is more common in women between the ages of 20-30 (66-69) pg 334( ACFAS). Symptoms include acute pain and inflammation aggravated by shoe gear.
Initial treatment includes open-backed shoes, NSAID therapy, injections aimed at eliminating pressure and inflammation in the symptomatic area. Adjunctive physical therapy can be helpful.
If symptoms do not improve surgery may be required.
Preventing heel pain entails reducing stress on that area of the body.
Treatment and testing must be directed to the causative factors. Generally, the longer the duration of the heel pain symptoms, the longer the period of duration to final resolution of the condition.
While mechanical factors are the most common etiology, other causes include traumatic, neurological, arthritic, infectious, neoplastic, autoimmune and other systemic conditions.
The most common cause for pain on the bottom of the heel are biomechanical abnormalities that lead to stress to pathologic stress of the plantar soft tissues (1-7, pg 329 ACFAS). Plantar fasciopathy affects approximately 10% of the U.S. population at some point during their lifetime and affects an estimated one to two million people per year in the United States ((1-4) page 40 Podiatry Today. A general consensus is that most patients with plantar heel pain have degenerative changes of the plantar fascia at the fibrocartilaginous enthesis attachments to the calcaneus (13, pg 24 Podiatry Today). Chronic cases show collagen degeneration and a number of changes including thickening, swelling within the calcaneus and calcification due to repetitive strain. Chronic conditions of ‘plantar fasciopathy’ can show decreased vascularity and cellularity which is thought to contribute to the poor healing of degeneration of the plantar fascia at the insertional site on the calcaneus (66, pg28 Podiatry today). Localized nerve entrapments of the medial calcaneal or muscular branch off the lateral plantar nerve may be a contributing factor (8-11), pg 329 ACFAS). Newer technologies are now also being employed in recognition that chronic heel pain is a form of non-healing tissue attached to the inferior aspect of the calcaneus.
Accounts for 10% of running-related injuries and 11-15 percent of all foot symptoms requiring professional medical care (1, pg 34 Podiatry Today.
Mechanical heel pain is defined as insertional heel pain of the plantar fascia with or without a heel spur. Plantar heel pain is responsible for the majority of mechanical heel pain cases.
Patients usually present with isolated pain upon initiation of weightbearing, either in the morning or arising from sitting after a period of rest. The pain tends to decrease after a few minutes, then returns as the day proceeds and time on the feet increases. Associated factors may include a high body mass index, tightness of the Achilles tendon, pain upon palpation of the inferior heel and inappropriate shoe wear. (12-14) pg 329 ACFAS)
Relevant questions include ‘when does the pain occur? Is there a history of trauma? What is the current shoewear and activity levels at work and leisure? Are there occuaptional/recreational activities with daily prolonged weightbearing and or walking on hard surfaces?
Physical exam includes range of motion of joints, especially decreased ankle dorsiflexion, palpation on the bottom of the heel, the occurrence of symptoms bilateral and angle and base of gait evaluation. Biomechanical studies show us that in the midstance phase of walking prior to heel off there is decreased dorsiflexion in lifting up the foot upon the ankle rang of motion leading to abnormal rearfoot plantarflexion and forefoot dorsiflexion moment that causes an increase in longitudinal tension to the plantar fascia as the tibia attemptes to pass over the planted foot.(5,13 Podiatry Today page 41. A tight gastroc-soleus complex can cause increased pronation in midstance as well as early heel-off in gait, which leads to knee extension and increased stress through the forefoot and plantar fascia (4-6, 14 Podiatry Today page 41). People with a tigh gastro-soleus often walk with a shorter stride length and increased stride time. These antalgic changes can lead to further muscle imbalance, resulting in loss of strength and flexibility.
X-rays may be considered. Identification of a plantar heel spur indicates that the condition has been present for at least 6-12 months, whether having been symptomatic or not.
Initial treatment options traditionally focus on relieving mechanical load on the insertion of the plantar fascia at the calcaneus. These may include patient-guided stretching exercises of the calf muscles, taping, heel pads, heel lifts, strapping of the foot, avoiding flat, non-supportive shoes and barefoot walking, over-the-counter arch supports, heel cushions and limitation of prolonged physical activities and use of plantar fascial night splints. Other therapies focus on inflammation reduction such as cryotherapy, nonsteroidal anti-inflammatory drugs (NSAIDS), corticosteroid injections in appropriate patients and physical therapy modalities such as Grastin to stretch the plantar fascial ligament mechanically and deep tissue needling to relax musculature to allow relax the musculature to allow for increased stretching. Ultrasound can break up scar tissue. Manual therapy helps facilitate flexibility, improving tolererance and range of motion when performed in conjunction with stretching exercises (3,7,30 Podiatry Today page 44). Self massage, foam rolling or therapy balls can also be helpful.
Usually within 6 weeks of initial treatment improvement is noted and the current therapy program is continued until resolution. However, if there is no or minimal improvement the patient should be referred to a podiatrist or foot specialist.
A second phase of treatment includes continuation of initial treatment options with consideration for additional therapy: the use of custom orthotic devices, especially for the biomechanically malaligned patient, the use of night splints to maintain an extended length of the plantar fascia during sleep (15-22) pg 330 (ACFAS). A limited number of corticosteroid injection (23,24 pg 330 ACFAS), and cast immobilization for 4-6 weeks or the use of a fixed ankle walker-type device to immobilize the foot during activity(25) pg 330 ACFAS). Appropriate weight-loss management consultation and referral should be considered in patients with a high body mass index. Clinical response to this second phase of treatment will usually occur within 2-3 months in 85-90% of patients (26-30), pg 330 ACFAS). For those who show improvement both phase 1 and phase 2 therapy should be continued until resolution. If no improvement, other systemic diseases should be considered (31-37, pg 330 ACFAS).
A third phase continues with the addition of cast immobilization if not already performed. Other treatment modalities include surgical plantar fasciotomy where a portion of the taut ligament is cut to allow for healing in an elongated position thereby reducing pull at the insertional site onto the heel. It should be noted that in the majority of cases, removal of the plantar heel spur does not seem to add to the success of the outcome in the surgical treatment of plantar heel pain (48, 59-61) page 330 ACFAS). Long term biomechanical control of excessive pronation forces or accommodation for high arches via orthotics is an essential element in permanent resolution of the symptoms.
Underneath the calcaneaus there is a medial and lateral calcaneal tubercle which can become inflamed directly underneath with repetitive friction, shearing or tight shoe fit or seam on the shoe resulting in subcalcaneal bursitis. More specifically, causes for heel bursitis include: excessive stress, direct trauma, plantar fascial strain relationship, posterior pulling effect with the achilles tendon creating tightness and contracture. Shoe gar issues can also precipitate friction and shearing forces. An inflamed bursa may have clear serous fluid associated with friction or shearing forces such as tight shoegear or hemorrhagic exudate within it associated with direct trauma.
Conservative treatment measures can include cortisone injections directly into the inflamed bursa, heel padding, orthotics, physical therapy with deep friction massage to break up the bursa, ultrasound +/- photophoresis with addition of steroid.
Black Heel Syndrome
Bruising from rubbing irritation of the capillaries of the heel against the heel counter. This is most commonly seen in runners. Treatment best consists of protective padding and/or injection of the inflamed bursa with cortisone. Asymptomatic bursa can also be removed surgically.
Plantar Fat Pad Atrophy
As we mature the fatty tissue layer underneath our heels becomes thinner with less shock absorption for the heel which can lead to pain.
Cushioned insoles, orthotics with accommodation can be helpful
is another modality where a patient’s blood is centrifuged to produce concentrated platelet values along with other blood components such as leukocytes and red blood cells. Platelets possess biologically active growth factors and 70 percent of these growth factors are released upon the activation of platelets. (61, pg 28 Podiatry Today). Platelet-rich plasma also reduces the inflammatory process (63, pg 28 podiatry today). Thus, the combination of growth and anti-inflammatory components of PRP are suited to initiate a healing phase in chronic plantar fasciopathy. (68, page 28 Podiatry Today .
This sends sound waves within the tissue to create a controlled injury and stimulate healing and a unique set of acoustic waves produced outside of the body to treat musculoskeletal conditions. (15,16) pg 25 Podiatry today). There is evidence that local tissue injury causes increased vascularization and growth factors. (15, pg 25 Podiatry today). Other proposed mechanisms revolve around pain relief by altering the small axons as well as chemical alteration of pain receptors for neurotransmission. (16, pg 25, Podiatry Today.
Application of visible or invisible laser light to the surface of the body can be used to treat a variety of musculoskeletal conditions (36, 38, pg 26 Podiatry today). Most treatments employ low-level laser light using either a gas laser which produces red light of wavelength between 594-632 nm or semiconductor lasers that have a wavelength between 780 and 905 nm.
The primary effect is on photoreceptors present in the cell membranes. Photostimulation, reportedly enhances cellular function and proliferation rates (39,40, pg 26 Podiatry today). There is also evidence that low-level laser light can dilate capillaries and activate angiogenesis (41, pg 26 Podiatry today). Low-level laser light therapy can also exert and anti-inflammatory effect.
High-intensity laser therapy uses a pulsed laser to deliver a significant amount more energy than low-level laser light. In a study, higher intensity laser therapy demonstrated better improvement in all parameters than the lower-intensity laser group (54, pg 26 Podiatry today)
A therapeutic regimen following these pathways as outlined leads to 90-95% symptomatic resolution within one year.
Posterior heel pain is the second most common location of mechanically induced symptoms. It is categorized as (1) insertional Achilles tendinitis, and (2) bursitis often associated with ‘pump bumps’ (Haglund’s deformity).
Insertional Achilles tendinitis most commonly presents with an insidious onset often leads to chronic posterior heel pain and swelling. Pain is aggravated by increased activity and pressure caused by shoegear. A palpable prominence may be appreciated both medially and laterally to the Achilles tendon. X-ray findings commonly show insertional spurring or erosions. An MRI is the best modality in assessing the degenerative changes inside the tendon.
Mechanical stress from biomechanical factors and overuse such as training errors, running up hills or lowering of the heel after wearing a heeled shoe can lead to calcific tendonitis where calcifications can be seen in the tendon. I’ve seen this in soccer players or more commonly after someone incidentally steps in a hole. The abrupt motion causes partial tears within the tendon which gradually fills with new bone formation. Often calcification can be palpable and painful within the tendon. There will be a limitation in dorsiflexion with contracture of the achilles tendon.
Os Trigonum Syndrome is more prominent in basketball players and ballet dancers with pain noted directly behind the ankle joint. It involves prominent process on the back of the heel or a separate center of ossification that never united to the talus which can impinge the nerve against the ankle joint capsule with extreme movements. This prominence can also become fractured and irritate the adjacent flexor hallucis longus tendon as the big toe flexes. Pain is more localized to just behind the ankle. An ankle diagnostic injection can be used to rule out other inflammatory conditions of the ankle.
Initial treatment is geared to reducing pressure to the area such as heel lifts–for short term treatment– orthotics, bracing, NSAID therapy, various physical therapy modalities including stretching exercises and Grastin and ultrasound to reduce scar tissue and increase vascularity and Deep Tissue Needling to relax musculature to allow for stretching, ice massage, night splints, Immobilization may be considered, especially in acute cases. Local corticosteroid injections are not recommended unless concurrent immobilization as it can weaken the tendon leading to rupture.
In recalcitrant cases, surgery may be indicated. Resection of the prominent posterior spur along with the affected diseased portion of the tendon and inflamed bursa. Detachment with subsequent reattachment of the Achilles tendon may be needed to ensure adequate resection of the spur.
is more common in women age 20-30 (66-69) pg 334( ACFAS). Symptoms include acute pain and inflammation aggravated by shoegear. Pain alleviation is noted with barefoot walking. Tenderness is noted on the outside of the achilles tendon usually associated with a palpable posterior lateral prominence which is demonstrated on X-rays on the posterior superior surface of the calcaneus.
Initial treatment such as open-backed shoes, NSAID therapy, injections is directed at eliminating pressure and inflammation in the symptomatic area. Adjunctive physical therapy can be helpful.
If symptoms do not improve surgery may be indicated. Resection of the prominent posterior superior aspect of the calcaneus and inflamed bursa is the indicated surgical procedure (64-70) pg 334, ACFAS)
In adolescents the most common cause of heel pain as the primary centers of the heel bone begin to unite during development. Symptoms include generalized pain and discomfort, especially on the sides of the heel with compression, primarily upon activity, especially running, basketball, baseball, soccer. The symptoms may progressively worsen and may eventually be noted with all weightbearing activities. In extreme cases the area may be edematous and erythematous. It involves inflammation of the growth plate. It is also referred to as ‘osteochondrosis’ and ‘avascular necrosis.’ It is typically found in 8-15 year-old age group (average age, 10-11 years) and generally affect males more than females. Radiographically, it will present as irregular appearance of the calcaneus, in extreme cases marked fragmentation with asymmetric findings. Tightness of the heel cord or posterior musculature can aggravate the condition Heel cups, orthotics, heel lifts and anti-inflammatory medications are most successful in pain alleviation which can often self limit.
While its prevalence in the general population is unknown, factors such as obesity, venous insufficiency, trauma, and space-occupying lesions may be factors because they can put pressure on the involved nerve (71-74) pg 334 ACFAS). Most cases present unilaterally. In bilateral presentations an underlying systemic disease process must be ruled out.
Is the result of entrapment or irritation of one or more of the nerves which innervate this region.
The posterior tibial nerve entrapment leads to tarsal tunnel syndrome, similar to carpal tunnel syndrome. Tarsal Tunnel Syndrome is a rare entrapment neuropathy that involves compression of the posterior tibial nerve or one of its distal nerve branches as it course beneath the flexor retinaculum (lacinate ligament) along the medial heel (5, page 36 Podiatry Today. Burning, numbness, pins and needles sensation (paresthesias) may radiate (Tinel’s Sign) to the heels and toes. Etiologies include trauma, flat feet (pes planus) morbid obesity, space occupying lesions such as ganglion cysts and lipomas, varicose veins, tumors and edema due to tendinitis.
Initial treatment include non-steroidal anti-inflammatory drugs for reduction of pain and inflammation along with rest, ice, compression and elevation. Wedges to invert the heel taking stress off the ‘porta pedis’ and posterior tibial nerve can be utilized or custom orthotics to correct foot posture and better support. Padding can also be beneficial to reduce pressure. If pain persists, consideration for immobilzation with cam walker boot and injection therapy may be indicated as well as referral to physical therapy. If pain is recalcitrant to these modalities, surgical decompression of the tibial nerve at the tarsal tunnel and its branches may be indicated. If a space occupying lesion (ganglion cyst or Lipoma) is the etiology it will likely have top be removed
If conservative treatment fails, magnetic resonance imaging (MRI) can be helpful with inspection for abnormality however sensory and nerve conduction velocities (NCV) as well as electromyography can confirm a tibial nerve lesion.
Entrapment of the medial calcaneal nerve can lead to neuroma of the heel. Other nerves that can be affected include the medial plantar, lateral plantar and branch to abductor digiti minimi, sural and lateral calcaneal nerve.
Neurologic pain can also be due to more proximal nerve impingement syndromes (71) pg 334 ACFAS)A more proximal nerve root pathology and evaluation for lumbosacral radiculopathy must be assessed for pain emanating from the low back. Researchers have noted an association between radiculopathy and plantar heel pain secondary to nerve entrapment, specifically at the L5 to S1 level (3, pg 35, Podiatry Today). Often this pain quality may be more diffuse and difficult to pinpoint.
If neurologic heel pain is suspected, appropriate diagnostic studies may include Electomyography (EMG), Nerve conduction velocity (NCV) and Magnetic resonance imaging (MRI) along with appropriate referral.
Upon review of reports a treatment protocol can be performed. The podiatric foot specialist may manage the local conditions in the foot and ankle with shoegear modifications and medications such as Gabapentin to treat neuropathic pain, while referral to appropriate specialists may be required if the pathology is found to emanate from the lumbar region.
Various systemic arthritides, such as seronegative arthritides, psoriatic arthritis, Reuters disease, diffuse idiopathic skeletal hyperostosis (DISH), rheumatoid arthritis, fibromyalgia, and gout (14,31,35,36, 76-115) pg 334 ACFAS). Enthesopathies 9pathology of the tendinous insertional site can also be seen in Chron’s disease. These patients may have other joint symptoms and should be questioned regarding concomitant arthralgias. Radiographic evaluation and laboratory testing with an Arthritis panel consisting of Rheumatoid factor, Uric Acid, ANA, Sedmentation rate for generalized non specific inflammation, C-reactive protein for acute inflammation Complete Blood count with differential, Alkaline Phosphatase and Calcium may be elevated with increased bone formation. Such lab work may facilitate proper diagnosis and treatment in these patients who may otherwise be non responsive. X-rays of the heel may reveal erosions or proliferative changes specific to the disease process. A rheumatology consult may be helpful.
Acute trauma with a fall from height onto the heel is the most common mechanism of injury.
Fractures can involve the subtalar joint and result in diffuse pain poorly localized in the rearfoot.
More focal symptoms may be noted in less severe injuries corresponding to the anatomic are of the fracture such as the sustentaculum tali, the plantar calcaneal tubercles, and avulsion of the posterior aspect of the tuber (128-135) pg 335 ACFAS. Diagnosis is made by a history of trauma, focal pain on palpation, and radiographic confirmation of the fracture. Treatment is often surgical when significant functional units are violated. In those cases where fracture fragments are small, and not involving joints or minimally displaced, treatment is typically immobilization.
Repetitive load to the heel can lead to stress fractures of the calcaneus. Often there is an associated antecedent increase in walking or history of walking on hard surfaces or increased weight gain. Clinically there is tenderness on the outside of the heel with pain often elicited with compression of the calcaneus. Swelling and warmth may be present. Diagnosis should be considered upon clinical suspicion and elicitation of such a history. Onset of symptoms often precedes radiographic findings. Ancillary measures can assist in early diagnosis such as Technetium bone scans which are highly sensitive for stress fractures of the calcaneus. Treatment is conservative and involves protection and immobilization of the involved foot (131, 137) pg 335 ACFAS). Redistribution of the plantar pressures via custom orthotics may be helpful. Progression to acute fracture is uncommon.
Soft tissue trauma such as an acute rupture of the plantar fascia can cause heel pain which may require immobilization or surgical repair. Acute tear is relatively uncommon. The patient will present with severe pain with weightbearing on the foot. This can occur more spontaneously in athletes or more active patients. Diagnosis is typically made clinically but ultrasound and magnetic resonance imaging (MRI) may be useful. The tear may be partial or complete. Those who receive multiple corticosteriod injections are at greater risk for acute tear due to the weakening and atrophy of the plantar fascial ligament (4, pg 35 Podiatry Today). Most patients respond well to conservative modalities with rest and immobilization over a month and NSAIDS. Operative treatment may b e necessary if there is no improvement with conservative treatment.
Benign and malignant tumors,infection and vascular compromise, although rare, must be considered as possible etiologies for heel pain. (34,77,149-158) pg 337 ACFAS.Os Trigonum Syndrome involves prominent process on the back of the heel or a separate center of ossification that never united to the talus which can impinge the nerve against the ankle joint capsule with extreme movements. This prominence can also become fractured and irritate the adjacent flexor hallucis longus tendon. Pain is more localized to just behind the ankle.
The maturing process with ‘fat pad’ atrophy.