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Blount’s Disease Physiotherapy

Blount's disease is a growth disorder that affects the shin (tibia) bone.

It's primarily characterized by the lower leg turning inward, causing the leg to appear bowed below the knee. Blount’s disease can affect

  • toddlers
  • children
  • adolescents

Although the exact cause of the condition is unknown, research has shown that its occurrence is associated with

  • obesity
  • low levels of vitamin D and
  • walking early (at 8 to 10 months or earlier)

Infantile onset of Blount’s disease most frequently affects African-American girls; both legs are affected in more than 70% of cases. When Blount's disease begins later in a child's life, African-American boys are more commonly affected, but children of any race or ethnicity may develop it in 1 or both legs.

Blount's disease is considered rare, with fewer than 200,000 people affected by it in the United States alone.

Physiotherapists help children and families manage the symptoms of Blount's disease at all stages by

  • teaching a child learn to walk with assistive devices
  • strengthening exercises to improve standing and walking abilities

What is Blount's Disease?

Blount' disease is a growth disorder of the lower leg bone (tibia), and is characterized by a bowing (pronounced boh-ing) appearance of the leg below the knee joint. Patients who have this condition can have either one or both legs affected.

Some children may experience shortening of 1 leg (termed as leg length discrepancy), or the turning of 1 or both feet inward.

Blount's disease is classified into 3 groups based on the age of the child:

  • Infantile (birth to 3 years of age)
  • Juvenile (4 to 10 years of age)
  • Adolescent (11 years and older)

Infantile Blount's disease occurs in children younger than 3 years of age, who

  • walk early
  • big/large or
  • are overweight

In these toddlers, the repeated stress and compression of the inside-top part of the shin bone causes the "growth plate" to slow down, or to stop the bone from growing on the inside of the leg, while the outside part continues to grow, causing an exaggeration of the typical bowing of the bone in the lower part of the leg.

"Growth plates" are made up of cartilage located at each end of a child's long bones, making the child grow taller by building bone on top of bone.

Some knee/leg bowing may always be present in the legs of children and adults.

Bowing of the lower leg in infants who are developing normally usually resolves by 2 years of age, when the legs bend slightly the other way and the child becomes "knock-kneed" during the third and fourth years of age.

By the age of 7 years, their legs will unfortunately achieve a different shape, with the knees appearing to fall inward slightly, and by the age of 12, all children's legs have grown into their adult shape.

The shape of the leg changes very little beyond this stage, although the bones and muscles continue to grow longer and thicker. If the bowing is not typical (doesn't have the shape of typical infant bowing, is unequal in the 2 legs or is extreme), then Blount's disease should be suspected. Your physician or physiotherapist will help distinguish between normal and abnormal bowing. Seek their advice if you are uncertain.

  • Juvenile Blount's disease affects children aged 4 to 10 years.
  • Adolescent Blount's disease affects children aged 11 and older.

These forms of the disease affecting older children are less common than the infantile form, and typically affect

  • large teenagers
  • boys more often than girls and
  • especially boys with a vitamin D deficiency

The upper and lower bones of the leg are often affected in both these forms of the disease.

The major difference between these two groups (juvenile and adolescent) is the age of the child when the bowing is noted, and how much growth the child has remaining. Physicians are able to use radiographs to estimate the amount of growth remaining.

Signs and Symptoms of blount's disease

Blount's disease may affect 1 or both legs; the most common symptom is a bowing from just below the knee to the ankle. The bowing will get worsen over tme as the child grows. In older children, the thigh bone may also be affected in addition to the shin bone.

The child with Blount's diease may not feel any symptoms, but adolescents may complain of pain on the inside of the knee joint and down the inside of the leg. The appearance of bowing may be the first noticeable symptom. To add to that, the way a child walks will look different; the child may

  • limp or
  • frequently trip with or without falling

The major difference in the nature and treatment of the disease is the age of the child when the bowing is noted, and how much natural growth time the child has remaining.

How Is blount's disease Diagnosed?

Blount's disease is diagnosed based on a

  • physical examination by a pediatric orthopedist and
  • by taking radiographic images of the legs

The physician will examine the child’s body, paying close attention to the legs, and will observe the child walking. The physician may measure the distance between the child’s knees when standing with the feet touching.

If there is a wide space between the knees, then the physician may need to do further testing.

The physician will order radiographic images because bowing of the bones can be seen more clearly on this type of image. Radiographs will allow the physician to confirm the diagnosis (or disprove it) and assign a number from I to VI to indicate the stage of the disease. Stage I is the mildest form and stage VI is the most advanced form.

The physician may also request a blood test to determine the vitamin D level in the blood.

How Can a PhysioTherapist Help?

Treatment of Blount's disease depends on the age of the child and the stage of the disease, but a physiotherapist will help during all stages.

Brace treatment is always considered first in children younger than 30 months, and in the beginning stage (Stage I) of the disease. The brace prescribed by the physician/doctor is called a

  • HKAFO (hip-knee-ankle-foot orthosis) or
  • KAFO (knee-ankle-foot orthosis)

which will help to redistribute the forces on the growth plate to foster normal growth.

The braces are typically custom-made by a specialist (orthotist) after casting or computer scanning of the leg to get precise measurements. Our senior physiotherapists will teach you and your child how to put on and take off the brace, and how to protect the skin.

We also will help your child learn how to walk and balance with the brace. Assistive devices, such as a child-sized rolling walker or crutches may be needed. We will teach your child how to safely and freely walk with the help of a walker or crutches.

The brace must be worn for about 1½ to 2 years to see resolution of the changes in the shape of the shin bone, but some improvement should be seen within the first year. Adjustments to the brace will be made as the child grows. If improvement is not noted within the first 12 months, the brace will be discontinued and surgery will be recommended.

Following Surgery

If Blount's disease has advanced, and/or if brace treatment is unsuccessful, or if the child is older than approximately 10 years of age, surgery may be necessary. To keep the leg in proper alignment during the healing phase following surgery, the surgeon will place another type of brace called a fixator on the leg, to be worn for 8 to 12 weeks.

While in the hospital following surgery, a physical therapist will teach your child how to walk using a walker or crutches. They will teach your child how to put the right amount of weight onto the foot (called weight-bearing), as prescribed by the physician to avoid injury to the surgical repair of the leg.

They will also teach you and your child specific exercises to help keep the leg healthy and regain strength and joint movement. Your physiotherapist will teach your child how to

  • transfer in and out of bed safely
  • how to use the bathroom
  • how to navigate curbs and stairs
  • how to get in and out of a car
  • prepare for the return home

After discharge home from the hospital, most patients will continue to see their physiotherapist 2 to 3 times a week at home or in an outpatient clinic.

Physiotherapy helps to ensure that

  • the surrounding leg tissues remain flexible as the bone heals
  • muscle strength is maintained
  • a child is independent with all daily activities
  • weight-bearing precautions are taken
  • a child only bears weight on the leg as allowed by the physician

Often, when the surgeon allows a child to put full weight on the operated leg to help the bone heal, children are hesitant about doing so (usually due to fear of pain, injury or uncertainty, all of which are normal and expected).

Of course, you can be assured that our physiotherapist will work with your child to safely increase the amount of weight-bearing on the operated leg in a fun and supportive way.

We also provide guidance and help with walking and strengthening for adolescents diagnosed with Blount's disease. As the adolescent’s natural growth occurs, the deformity may slowly be corrected.

However if this approach fails, or if the older adolescent does not have enough growth time left to achieve the correction, surgery may be recommended. Our senior physiotherapists will help ensure that recovery is safe and effective following surgery.