Blount's Disease

What is Blount’s Disease?

Blount’s disease results in a bowlegged appearance of one or both knees. The bowing out of a child’s knees will appear as if the knee bends out to the sides. There are two main types of Blount’s disease: the infantile (early-onset) variant and the adolescent (late-onset) variant.

Infantile variant

X-ray showing example of early-onset Blount's disease with unilateral out bowing of knee. 
(An example of early-onset Blount disease with unilateral out bowing of knee)

The infantile variant can present similarly to normal bowing of the legs. This is common in children under the age of 2. Normal bowing (genu varum) will usually begin to resolve around the age of 18-24 months. In most cases, it will completely resolve by 4 years of age. Infantile Blount’s disease is different because the condition of the bowing worsens over time. The exact cause is unknown of this disease is unknown. Children with the infantile variant are commonly overweight and start walking earlier (before 10 months). The extra weight puts stress on their under-developed knees. This variant can run in families and can affect both knees.

Adolescent variant

The adolescent variant is less common. It normally presents in children after the age of 10. These patients are usually obese and only have bowing on one side (unilateral).

How is Blount’s Disease Diagnosed?

Blount’s disease diagnosis is by a combination of physical exam and X-ray. The doctor may also order a magnetic resonance imaging (MRI) test.

How is Blount’s Disease Treated?

Patients with mild cases may be treated with braces to start. The goal of these braces is to gradually straighten the growth of the legs. However, if normal knee growth is not seen by the age of 4, surgery may be necessary.

Patients with the adolescent variant will often require surgery. Deciding on when to perform the surgery depends on their age and the severity of their disease.

What is the Prognosis of Blount’s Disease?

Children are normally able to resume the activities of their daily lives once the deformity is corrected. It is important to check-up with your child’s doctor throughout your child’s development to monitor their growth progression.