Assessment of Pediatric Limb Length Inequality

Limb length inequality or discrepancy (LLD) occurs when there is a difference in length between 2 limbs or when deviation exists from a normally expected length for a given age. The magnitude of the discrepancy is defined as the difference between the 2 extremities. Aside from congenital etiologies, LLD can also arise from infection, paralysis, tumors/neoplasm, and surgery. Approximately 70% to 90% of the world's population has some elements of LLD with compensation allowing for tolerance and potentially masking the extent to which one limb could be significantly shorter either functionally or structurally. Components of functional LLD could include congenital shortening of soft tissues, joint contractures, axial skeleton malalignment, and abnormal pedal biomechanics (ie, posterior tibial tendonitis or equinovarus). In accordance with literature reports, most individuals can tolerate upwards of a 2 cm discrepancy. Although a constellation of symptoms such as joint pain, arthritis, alterations in oxygen consumption/heart rate, and low back pathology can occur later on in adulthood, the focus in this review will be with early diagnosis and management in the pediatric population.