Limb length discrepancy is a type of deformity that occurs when the growth of one leg has been stunted. This can occur after a trauma to the femur or tibia bone such as a break, tumor, or infection. The damaged bone may grow more slowly than the bone in the healthy leg, causing different lengths to occur. 

This deformity is usually noticed by parents as a child begins to crawl or walk. A child may be born with different leg lengths, or the condition may be caused by an illness or injury that develops over time. A slight difference in the length of the legs may not cause any symptoms. However, a significant limb length discrepancy may cause a limp and make it difficult to perform normal activities. A serious difference in the length of the legs can also be harmful to the hips and other bone structures as the person ages. Limb lengthening surgery can help restore mobility and function for those with limb deformities or limb length discrepancy.