Table 1. Structural (Anatomical) and Functional Causes of Leg Length Discrepancy.
| Type of LLD | Definition | Subcategory | Possible cause | |
|---|---|---|---|---|
| Structural (anatomical) | Physical shortening or lengthening of the tibia or femur | Congenital | Limb shortening | |
| • Fibular hemimelia, tibial hemimelia | ||||
| • Proximal focal femoral deficiency | ||||
| • Skeletal dysplasias Limb lengthening | ||||
| • Congenital hemihypertrophy (idiopathic non-syndromic hemihypertrophy) | ||||
| • Dysmorphic syndromes (Beckwith-Wiedemann syndrome; proteus syndrome, Klippel-Trenaunay-Weber syndrome) | ||||
| • Gigantism with neurofibromatosis | ||||
| Acquired | Shortening | |||
| • Trauma (Salter-Harris fractures, slipped capital femoral epiphysis, iatrogenic) | ||||
| • Infection (osteomyelitis, septic arthritis) | ||||
| • Osteonecrosis following developmental dysplasia of the hip | ||||
| • Inflammation (juvenile idiopathic arthritis) | ||||
| • Neoplasms | ||||
| • Radiation | ||||
| • Idiopathic (Blount disease or Legg-Perthes disease) | ||||
| • Neurologic disorders (cerebral palsy, polio, peripheral nerve injury) Lengthening | ||||
| • Neoplasms | ||||
| • Osteomyelitis stimulating growth plate | ||||
| • Chronic hyperemia | ||||
| Functional | Apparent asymmetry of the lower extremity, without shortening or lengthening of the osseous components of the lower limb | Pelvic obliquity due to | ||
| • Adaptive soft-tissue shortening | ||||
| • Joint or muscle contractures | ||||
| • Ligamentous laxity | ||||
| • Axial malalignment | ||||
| • Developmental dysplasia of the hip | ||||
LLD: leg length discrepancy.