As you have probably learned, Blount disease is a condition also referred to as “bowlegs”. The medical term is tibia varum (singular) or tibia vara (plural). Tibia refers to the lower leg or “shin” bone. Varum is the Latin word for bow-legged. This condition is common in toddlers and young children.
The condition is called physiologic tibia varum when it’s a normal variation and the child will grow out of it. Most toddlers have bowlegs from positioning in utero (in the uterus). This curvature remains until the muscles of the lower back and legs are strong enough to support them in the upright position.
In some cases abnormal growth of the bone causes the bowing to get worse instead of better over time. That’s when it is called Blount’s disease or pathologic tibia varum. Blount’s disease becomes obvious between the ages of two and four as the bowing gets worse. Overweight adolescents or teenagers can also develop Blount’s disease.
All of a sudden, growth at the proximal end of the tibia (upper portion of the lower leg at the knee) slows down or even stops. This change in growth is referred to as physeal arrest). Along with physeal arrest comes a curving (bowing) or varus deformity and internal rotation (“torsion”) of the tibia.
Treatment for infantile Blount disease is on a continuum from wait-and-see (sometimes the problem corrects itself) to conservative (nonoperative) care using braces and finally, surgery to correct the deformity. According to an expert in this area (Dr. J. G. Birch from Texas Scottish Rite Hospital for Children), treating infantile Blount disease with bracing can be used effectively for children up to age three. This fits with your situation.
Children who do not respond to the bracing are candidates for growth modulation or surgical correction of the deformity. Growth modulation refers to the use of small tension band plates and screws to guide growth and correction of the deformity. The most common surgical procedure done (before permanent damage occurs) is called a tibial osteotomy.
In an osteotomy, a wedge-shaped piece of bone is removed from the medial (inner) side of the femur (thigh bone). It’s then inserted into the tibia to replace the broken down inner edge of the bone. Hardware such as pins and screws may be used to hold everything in place. If the fixation is used inside the leg, it’s called internal fixation osteotomy. External fixation osteotomy describes a special circular wire frame on the outside of the leg with pins to hold the device in place.
Your surgeon will advise you regarding your child’s growth and progress. If all goes well, there will be no need for anything further after bracing. Your child will need ongoing observation and evaluation to make any corrections needed as he (or she) grows. The condition can come back, so if that happens, early intervention is always encouraged.