Some people develop limb length discrepancy, but it’s possible to be born with some degree of inequality. The limb length difference can either remain the same during growth (called static limb length discrepancy), or the difference can worsen during growth (called dynamic limb length discrepancy).
Congenital disorders (conditions existing at or before birth) may cause growth abnormalities that contribute to limb length discrepancy. Generally, it’s more common for congenital disorders to stall limb growth, but some rare conditions may cause accelerated growth as well.
Hemihypertrophy and hemiatrophy are congenital disorders that cause growth disparity between the two sides of the body – making one leg longer than the other. Hemihypertrophy causes one half of the body to grow faster than the other, whereas hemiatrophy refers to a condition in which one half of the body is shorter than the other. Patients with these conditions generally have a milder degree of shortening than those with other congenital disorders.
Other congenital disorders that cause limb length discrepancy include:
- Fibular hemimelia – congenital shortening or absence of the calf bone (fibula)
- Tibial hemimelia – congenital shortening or absence of the shin bone (tibia)
- Proximal femoral focal deficiency – congenital defects in the hip or thigh bone (femur), leading to a shorter leg
- Femoral hemimelia – congenital shortening or absence of the thigh bone
- Coxa vara – congenital or development deformity of the hip that leads to a shorter leg
- Posteromedial bowing of the tibia – congenital bowing of the shin bones
- Developmental dysplasia of the hip – congenital condition in which the hip joint doesn’t develop normally
Cases of congenital limb length discrepancy are often challenging. Not only may there be a greater inequality in limb length, but it also increases proportionally during growth. Before committing to a treatment plan, it’s important to find a surgeon who specializes in limb length discrepancy, and who has significant experience with lengthening of congenital limb length discrepancy.