© Springer-Verlag France 2015
Cyril Mauffrey and David J. Hak (eds.)Passport for the Orthopedic Boards and FRCS Examination10.1007/978-2-8178-0475-0_23Limb-Length Discrepancy
(1)
Pediatric Orthopedics, Childrens’ Orthopedic Centre, Mumbai, India
Take-Home Message
Limb equalization procedures must take into account the final projected LLD, not the LLD present at the time of surgery.
Scanogram provides reliable measurements with minimal magnification; however, a full-length standing AP computed radiograph (teleoroentgenogram) is a more comprehensive assessment technique, with similar costs at less radiation exposure.
A proximal fibular epiphysiodesis should be included with proximal tibial epiphysiodesis if more than 2–3 years of growth remain.
Undercorrection of an LLD associated with paralysis facilitates the foot clearing the floor during the swing phase of gait and is especially important if the patient walks with a brace in which the knee is locked in extension.
Overview
Differences between the lengths of the upper and/or lower arms and the upper and/or lower legs are called limb-length discrepancies (LLDs).
Small (up to 2 cm) limb-length discrepancies (LLDs) are common, occurring in up to two thirds of the general population.
Secondary Problems from LLD
Gait problems, such as limping, toe-walking, or rotation of the leg. A knee that is chronically hyperextended on the short side and flexed on the long side.
The prevalence of back pain may be higher with large discrepancies (>2 cm), but the evidence is limited.
During double-limb stance, the hip on the long side is relatively less covered by the acetabulum. Osteoarthritis is seen more commonly (84 % of the time) on the long-leg side.
LLD increases the incidence of structural scoliosis to the short side. In up to one third of cases, the scoliosis is in a noncompensatory direction.
Etiology
An injury, such as in a fracture that damages the cells responsible for growth of the bone, while the corresponding bone on the other leg grows normally. Some fractures can also lead to overgrowth of the bone during the healing process.
Diseases of the bone, such as osteomyelitis, can injure the growth plate, so that a discrepancy occurs gradually over time.
Congenital conditions
Bone tumors and treatments designed to eradicate them.
Functional leg-length discrepancy can also result from congenital problems that alter alignment of the hips, such as coxa vara and developmental dislocation of the hip.Related posts:
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