This is a more rare congenital deficiency (reported as 1 in 1 million) that involves the tibia (larger inner bone) in the leg. It can vary from a mild amount of shortening to complete absence of the bone. The knee joint and ankle joints tend to be affected to some degree. Some forms of tibia hemimelia are inherited, while others occur with no apparent cause. Often times (approximately 50%), tibia hemimelia can be associated with other conditions such as congenital femoral deficiency, an absent patella (knee cap), or a clubfoot. In approximately 30% of cases, tibia hemimelia is bilateral
Findings are typically noticeable at birth as the lower portion of the leg is visibly smaller and thinner compared to the other side. The knee often times in stuck in a bent position. The foot may rest in an abnormal position (often pointing down and in as in a clubfoot), and some of the toes may be missing. An x-ray can confirm the diagnosis.
For tibia hemimelia, treatment is based on the presence or absence of a tibia bone, how short the limb is projected to be as well as the functionality of the knee and ankle joints. Similar to fibula hemimelia, the goal is to have your child maximize his or her functional potential and have the limbs be close in length by the time they are finished with childhood. Sometimes, this is best accomplished with a limb lengthening procedure, and other times, a prosthesis may be a better option. Again, this is a discussion with your COA physician about which treatment is best indicated for your child.