Blount's disease / Tibia vara / Bow legs

Blount's disease is a disorder of the tibial growth plate (usually the medial aspect) leading to changes in the angle at the knee. 

This results in bowing of the leg (usually the lower leg). 

However, unlike bow legs it is pathological and progressively worsens. 

Clinically it is difficult to distinguish between simple bowlegs and Blount's disease. 

However, bow legs should resolve between the ages of 2-4 years - if not then one should suspect Blount's disease.[1]


Infantile Blount's disease[2]


Presents at age 2-4 years

Risk factors

Repetitive trauma to a knee with an already varus abnormality



Plain radiographs show increased angulation between the metaphysis and the longitudinal axis of the tibia.

Differential diagnosis[3]



Adolescent Blount's disease[5]

Usually the adolescent variety is less severe than infantile Blount's disease.

Risk factors



Plain radiographs, as for infantile Blount's disease.


High tibial osteotomy is usually the procedure of choice. This is attractive, as limbs are not shortened; however, it requires the wearing of an external fixator for several months.