Calcaneal Apophysitis (Sever Disease)

The calcaneal apophysis develops as an independent center of ossification (possibly multiple). It appears in boys aged 9-10 years and fuses by age 17 years; it appears in girls at slightly younger ages. During the rapid growth surrounding puberty, the apophyseal line appears to be weakened further because of increased fragile calcified cartilage.

Microfractures are believed to occur because of shear stress leading to the normal progression of fracture healing. This theory explains the clinical picture and the radiographic appearance of resorption, fragmentation, and increased sclerosis leading to eventual union. The radiographs showing fragmentation of the apophysis are not diagnostic, because multiple centers of ossification may exist in the normal apophysis, as noted. However, the degree of involvement in children displaying the clinical symptoms of Sever disease appears to be more pronounced.

Sever disease, like other similar conditions (eg, Osgood-Schlatter disease, little-leaguer's elbow, and iliac apophysitis), is believed to be caused by decreased resistance to shear stress at the bone–growth plate interface. Studies have indicated that traction apophyses have a higher composition of fibrocartilage than epiphyses subjected more to axial load, which are composed predominantly of hyaline cartilage.[12]

The anatomy of the calcaneal apophysis lends to significant shear stress because of its vertical orientation and the direction of pull from the strong gastrocnemius-soleus muscle group (see the image below).

Labeled MRI depicts the anatomy and mechanical forces responsible for the development of Sever disease (shear stress at the calcaneal apophysis).

In a study of 56 male students from a soccer academy, of whom 28 had Sever disease and 28 were healthy control subjects, findings suggested that higher heel plantar pressures under dynamic and static conditions were associated with Sever disease, though it was not established whether the elevated pressures predisposed to or resulted from the disease.[13] Gastrocnemius ankle equinus also appeared to be a predisposing factor.[14]

Martinelli et al, in a study of 430 athletic children (soccer, 29.5%; basketball, 48.1%; volleyball, 22.3%) whose ages ranged from 6 to 14 years, found that the risk of calcaneal apophysitis was significantly higher in younger individuals, in those who had fewer training sessions over the course of a week, and in those whose training sessions were shorter.[15]

Sever disease is a relatively common problem in growing active children, though little in the way of exact incidence figures has been available. Wiegerinck et al, in a 2014 cross-sectional study described as the first report on the incidence of calcaneal apophysitis in the general population, examined the records of children aged 6-17 years who visited 34 general practices in the years 2008, 2009, and 2010.[16]  A total of 16,383 files were searched, and 61 children with this condition were diagnosed, for an incidence of 3.7 per 1000.

Sever disease occurs most frequently in active 10- to 12-year-old boys. In a report by Micheli and Ireland that included 85 patients, the average age of presentation was 11 years 10 months for boys and 8 years 8 months for girls[17] ; 64% of the 85 patients were male. In a study by Duong et al, the average age was 10.4 ± 1.9 years for boys and 9.2 ± 2.2 years for girls.[18]

Although no well-recognized, long-term sequelae of untreated Sever disease exist, this condition causes pain that can limit performance and participation in sports and, if left untreated, can significantly limit even simple activities of daily life.

In a retrospective 10-year study of calcaneal apophysitis in adolescent athletes from a German youth soccer academy (N = 22; mean age, 11.8 ± 2.1 y), Belikan et al found that the mean time to return to play was 60.7 ± 64.9 days.[19] Recovery time and time to return to play were longer in patients with recurrent complaints. Neither age nor body mass index at diagnosis could be shown to have an impact on time to return to play.

The typical clinical presentation of calcaneal apophysitis (Sever disease) is an active child (aged 9-10 years) who complains of pain at the posterior heel[20] that is made worse by sports, especially those involving running or jumping. The onset is usually gradual.

Often, the pain has been relieved somewhat with rest and consequently has been patiently monitored by the patient, parents, coaches, trainers, and family physicians, in the expectation that it will resolve. When the pain continues to interfere with sports performance and then with daily activities, further consultation is sought.

It should be kept in mind that failure to instruct patients and parents that continual pain, significant swelling or redness, and fever are not signs of Sever disease (and therefore require further evaluation) could result in failure to diagnose a condition with much more serious long-term consequences.

Physical examination varies, depending on the severity and length of involvement. Bilateral involvement is present in approximately 60% of cases. Most patients experience pain with deep palpation at the Achilles insertion and pain when performing active toe raises. Forced dorsiflexion of the ankle also proves uncomfortable and is relieved with passive equinus positioning. Swelling may be present but usually is mild. In long-standing cases, the child may have calcaneal enlargement.

Radiographic findings in calcaneal apophysitis (Sever disease) include increased sclerosis and fragmentation of the calcaneal apophysis. However, it should be stressed that these findings are nonspecific and also are observed in asymptomatic feet (see the image below).

Sever disease. Lateral radiograph of foot in symptomatic 9-year-old male soccer player. Sclerosis is not diagnostic of Sever disease but is a characteristic radiographic finding.

Radiographic evaluation is beneficial for excluding fracture or rare tumor. It is vital to remember that radiographic changes on plain films are neither diagnostic nor prognostic; their primary value in this setting is for exclusion of other causes of heel pain. This point should be clearly explained to patients and parents.[21]

It must be kept in mind that if pain continues, becomes significant at rest, awakens the patient from sleep, or is associated with significant swelling, tests should be performed to look for other causes. Tarsal coalition is another hindfoot disorder that must be distinguished from Sever disease. Thus, if reduction of subtalar motion is found on physical examination, computed tomography (CT) can be helpful in differentiating this disease from failure of the bones of the hindfoot to separate.

In cases of high suspicion, magnetic resonance imaging (MRI) may be of use for ruling out osteomyelitis (see the image below).

Transverse MRI of foot in symptomatic 11-year-old girl with heel pain showing osteomyelitis. Pain was increased with activity but more constant and with more associated night pain than expected with Sever disease. Treatment included surgical debridement and antibiotic therapy.

Sever disease is characterized by disorder of the normal process of enchondral ossification.

As children become involved in sports at younger ages and compete at higher levels and as expectations of the participants, parents, and coaches increase, incidence of overuse syndromes increases in growing athletes.[22, 23] When Sever disease (calcaneal apophysitis) occurs, the pain that the child experiences not only can limit performance and participation but also, if left untreated, can significantly limit even simple activities of daily life. This raises concern in all persons involved.

Although no well-recognized, long-term sequelae of untreated Sever disease exist, the physician's role is to minimize pain and allow the child to return to normal activities as soon as possible to enhance psychosocial development. The physician also must be able to differentiate Sever disease from other causes of heel pain in the child that are potentially more serious, such as tumor or osteomyelitis.

Treatment is initially focused on reducing the present pain and limitations and then on preventing recurrence. Limitation of activity (especially running and jumping) usually is necessary. In Micheli and Ireland's study, 84% of 85 patients were able to resume sports activities after 2 months.[17]

If the symptoms are not severe enough to warrant limiting sports activities or if the patient and parents are unwilling to miss a critical portion of the sport season, wearing a half-inch inner-shoe heel lift (at all times during ambulation), a monitored stretching program, presport and postsport icing, and judicious use of anti-inflammatory agents normally reduce the symptoms and allow continued participation. If symptoms worsen, activity modification must be included.

Perhamre et al, building on data showing that the use of insoles in Sever disease could reduce pain without necessitating limitation of physical activity, compared two insole types (heel wedge and heel cup) in 51 boys with this condition to determine which type was more effective for this purpose.[24] More than three quarters of the patients preferred the heel cup. All patients maintained a high level of physical activity throughout the study.

Use of custom-made foot orthoses may yield improved benefit as compared with use of "off-the-shelf" heel lifts.[25]

For severe cases, short-term (2-3 weeks) cast treatment in mild equinus can be used.

Although several studies have shown that heel inserts and prefabricated orthotics may initially improve pain scores and dysfunction, patients appear to have equal improvement by 3 months with or without therapy.[26]

Limitation of activity (especially running and jumping) usually is necessary (see Medical Care). Failure to instruct players, parents, coaches and trainers regarding limitation of activity and proper preexercise and postexercise stretching can lead to prolonged symptoms and further limitation of performance.

To prevent recurrence, patients, parents, coaches, and trainers should be instructed regarding a good preexercise stretching program for the child. Early in the season, encouragement should be given for a preseason conditioning and stretching program. Coaches and trainers should be educated about recognition of the clinical symptoms so that they are able to initiate early protective measures and seek medical referral when necessary.

Judicious use of anti-inflammatory agents may be helpful for patients wishing to avoid limiting their sports activities (see Treatment, Medical Care).

Class Summary

Have analgesic, anti-inflammatory, and antipyretic activities. Their mechanism of action is not known, but they may inhibit cyclooxygenase activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell-membrane functions.

Ibuprofen (Motrin, Ibuprin, Excedrin IB, Advil)

DOC for patients with mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.

Naproxen (Naprosyn, Naprelan, Anaprox)

For relief of mild to moderate pain; inhibits inflammatory reactions and pain by decreasing activity of cyclo-oxygenase, which results in a decrease of prostaglandin synthesis.