Sever disease or calcaneal apophysisits was first described by JW Sever in 1912.  Sever disease is a painful inflammation of the calcaneal apophysis. It is considered as adolescent nonarticular osteochondroses  just like Iselin disease.
A repetitive pull of the tendocalcaneus on its insertion is thought to be responsible for this entity. The problem occurs in growing age and occurrence is more in children who actively participate in sports.
Sever disease can affect the performance in sports and, if left untreated, can significantly affect the daily activities of life also.
Severe disease occurs in growing age only before apophysis fuses with calcaneum as apophysis is quite a weak structure in comparison to Achilles tendon which exerts the force on it.
Sever disease is a self-limiting condition. The exact incidence of Sever disease is not known but the occurrence is more in boys than girls.
It mostly occurs in 9 to 12-year-old boys. The condition is bilateral in 60% of the cases.
Causes and Pathophysiology of Sever Disease
Sever disease, like other similar conditions, is believed to be caused by decreased resistance to shear stress at the bone–growth plate interface.
Calcaneal apophysis undergoes a significant amount of shear due to its vertical orientation and the direction of pull from Achilles tendon.
The calcaneal apophysis appears in boys around 9 years of age and slightly early in girls. It fuses by 17 years of age.
During the rapid growth surrounding puberty, the apophyseal line appears to be weakened due to the fragile nature of calcified cartilage.
Shear stress of repeated microtrauma leads to microfractures which may be in different stages of healing showing the appearance of resorption, fragmentation, and increased sclerosis
Presentation of Sever Disease
The typical presentation is of gradual onset heel pain in an active growing child of 9-10 years old, which becomes worse with activity especially those involving running or jumping. The pain gets somewhat relieved with rest.
On examination, there is tenderness at the insertion of Achilles tendon. There is a pain on performing active toe raises and forced dorsiflexion of the ankle. Mild swelling may be present. Calcaneus may show enlargement but usually is mild. In long-standing cases, the child may have a calcaneal enlargement.
Sever disease is typically not associated with continuous pain, significant selling or redness over the heel. These signs and presence of fever should alert the clinician to review the diagnosis.
Differential Diagnoses of Sever Disease
- Achilles tendon conditions
- Calcaneus fractures
- Tarsal Coalition
Not required for diagnosis.
X-rays show increased sclerosis and fragmentation of the calcaneal apophysis. These finding, however, are not specific and could be present in patients without symptoms. The x-rays may not be needed for reaching at diagnosis but x-ray findings do help to exclude other causes of heel pain. If a diagnosis of calcaneal apophysitis is made without obtaining radiographs, a lesion requiring more aggressive treatment could be missed. 
CT is helpful in differentiating Sever disease from tarsal coalition.
MRI may be required to differentiate osteomyelitis in cases with clinical suspicion.
Treatment of Sever Disease
Rest and limitation/modification of activity is the mainstay of the treatment. The initial goal of the treatment is the reduction of pain and the long-term goal is the prevention of recurrence.
Use of inner-shoe heel lift during ambulation relaxes Achilles tendon.
Icing and NSAIDs are used for the reduction of the symptoms.
In severe cases or those which do not respond to above treatment, a cast for 3 weeks in mild equinus can be used.
- Sever JW. Apophysitis of the Os Calcis. New York Medical Journal. 1912;95:1025-1029.
- Pappas AM. The osteochondroses. Pediatr Clin North Am. Aug 1967;14(3):549-70.
- Weiner DS, Morscher M, Dicintio MS. Calcaneal apophysitis: simple diagnosis, simpler treatment. J Fam Pract. May 2007;56(5):352-5.
- Rachel JN, Williams JB, Sawyer JR et-al. Is radiographic evaluation necessary in children with a clinical diagnosis of calcaneal apophysitis (sever disease)?. J Pediatr Orthop. 2011;31 (5): 548-50