Sever's disease, also known as calcaneal apophysitis, is an inflammatory condition of the growth plate of the heel (calcaneus.) Sever's disease is seen during periods of active bone growth, particularly between the ages of 10 and 14 years of age. Sever's disease is a self-limiting condition, meaning that all cases of Sever's disease will disappear once bone growth is finalized and the growth plate of the heel closes. Skeletal maturity and closure of the growth plate occurs for most children at 15-16 years of age. The onset of Sever's Disease is insidious and found more in boys than girls.
In the growing child, there are a number of different ways that bones grow. In the calcaneus (heel bone), growth comes from two separate growth plates. The lesser of the two growth plates is called the apophysis. The apophysis of the calcaneus is located between the back and the bottom of the heel at the spot that hits the ground each time we take a step. The Achilles tendon, which is the most powerful tendon in our body, attaches to the proximal aspect of the apophysis. The plantar fascia attaches to the distal aspect of the apophysis. Both the Achilles tendon and plantar fascia place traction, or pulling, on the growth plate and contribute to inflammation of the secondary growth plate called the apophysitis. The calcaneal apophysis is very apparent on x-ray and continues to grow until approximately age 12 in girls and age 15 in boys.
The calcaneus is very firm on the outside (cortical bone) and very soft and spongy on the inside (cancellous bone). Load is applied to the calcaneus in two ways. First, direct load is applied to the calcaneus with each step that we take. This load is equal to or greater than the mass of our body. Second, traction load is applied to the calcaneus by the structures that are attached to it that pull against the bone. Proximally, the Achilles tendon pulls on the calcaneus. Distally, muscle and fascia resist the load applied to the calcaneus by the Achilles tendon.
The calcaneal apophysis is unique in that it is affected by both of these types of load bearing. The calcaneal apophysis must accommodate the pull of the Achilles tendon on the posterior heel and the resistance of the plantar fascia on the bottom of the heel. In addition to the plantar fascia, several other soft tissue structures pull on the plantar aspect of the heel including muscle and ligaments. The pull of each of these soft tissue structures works much like a lever arm and results in mechanical load being applied to the calcaneal apophysis. For additional information on how the leg and foot perform as a lever arm, please refer to our pages on CT Band Syndrome.
Interestingly, Sever's disease is found in young boys who overload the apophysis with both body weight and mechanical load. Most cases of Sever's disease are found in young boys (8-12 y/o) who are overweight and have recently started a new physical activity. This combined load of body mass and increased mechanical load results in an inability of the growth plate to function normally. The heel pain experienced by children with Sever's disease is an inflammatory response of the growth plate to this increased load.
Most cases of Sever's disease show findings of equinus, or tightness of the calf muscle. How do you measure equinus? Equinus can be determined by measuring the range of motion of the ankle with the knee flexed and extended. When the knee is flexed, the amount of equinus of the soleus muscle is measured. With the knee extended, both the soleus and gastrocnemius muscles are measured. Imaginary lines are established on the long axis of the leg and the foot. By dorsiflexing the foot (toward the body) an angular measurement is established between these two lines. Normal range of motion of the ankle, to complete a normal gait cycle, is 10 to 15 degrees beyond 90 degrees. This means that the normal range requires the ankle to dorsiflex to 90 degrees plus an additional 10 to 15 degrees. An inability to complete this range of motion is termed equinus.
In summary, the biomechanical forces that contribute to Sever's disease include both traction applied to the bone and the load applied to the heel at the heel strike phase of the gait cycle. The pain experienced by children with Sever's disease is simply due to a growth plate that cannot keep up with the demands applied to it.
Causes and contributing factors
The cause of Sever's Disease is an overload of the calcaneal apophysis by body weight and mechanical load applied to the calcaneus by the Achilles tendon. Contributing factors include obesity and wearing low-heeled shoes.
The treatment of Sever's disease depends upon the severity of symptoms experienced by the patient. Care is initiated with a simple program of stretching and heel elevation to weaken the force applied to the calcaneus by the Achilles tendon. If stretches and heel lifts are unsuccessful in controlling the symptoms of Sever's disease, children should be taken out of sports and placed on restricted activities.
Mild Symptoms - Wear a 3/8 heel lift at all times (not just during physical activity.) It is important to use a firm lift and not a soft heel pad. Calf stretches 6/day for 60 seconds each. Calf stretches are best accomplished by standing with the toes on the edge of a stretching block.
Moderate Symptoms - Follow the directions for minor symptoms and decrease activity, including the elimination of any athletic activity. In addition to stretching by day, a night stretching splint can be worn while sleeping.
Severe Symptoms - Follow the directions for mild and moderate symptoms. Children should be removed from sports activities such as football, basketball, soccer, or gym class. A below-knee walking cast with a heel lift or in severe cases, non-weight bearing fiberglass cast, may be indicated for 4-6 weeks. The cast should be applied in a mildly plantar-flexed position. Cam Walkers should not be used for Sever's Disease unless they have a built-in heel lift.
Return to sports is dependent upon pain. Return should be gradual, continuing the use of the heel lift and calf stretches.
When to contact your doctor
Heel pain in children that fails to respond to conservative care should be evaluated by your podiatrist or orthopedist.
References are pending.
Author(s) and date
Competing Interests -None
Cite this article as: Oster, Jeffrey. Sever's Disease. http://www.myfootshop.com/article/severs-disease
Most recent article update: February 28, 2018.
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