The common types are; anatomical, functional, and combined (anatomical and functional).
Observe for a presence of scoliosis with the patient in a standing position. Then, observe the disappearance of scoliosis when the patient sits down. You can assume a functional shortening if patient’s scoliosis disappears during sitting down.
In structural discrepancy, anterior and posterior portions of the pelvis is usually low on the short leg side.
Typically, causes associated with leg length asymmetry included but not limited are the flat foot,
genu valgum, coxa vara, poor standing posture, or asymmetry in bone growth (Kisner 716).
Also, weakness of gluteus medius, over-lengthening of the limb during surgery, malpositioning of
prosthetic component (usually acetabular component), recurrent postoperative dislocation, and
total hip arthroplasty (Kisner 727) and open reduction and internal fixation (Kisner 739).
|Unilateral Short Leg||Unilateral Long Leg|
|Same side Pelvic drop|
|Side bend the trunk (lumbar) to the opposite side||Side bending toward the same side|
|Rotation of the lumbar spine to the same side (Ref)||Lumbar rotation to the opposite side|
|Convexity of the lumbar spine to the same side|
|Flexion and distraction of the lumbar facets||Extension and compression of the lumbar facets|
|Coxa Vara||Coxa Valga|
|Genu Valgum||Genu Varum|
|Lowered ilium||Elevated ilium|
|Hip Abduction||Hip Adduction|
|Vertical Sacroiliac joint|
|Increased compression stress on SI Joint/hip joint||Increased shear stress on SI joint/hip joint|
|Tight hip abductors||Tight hip adductors|
|Stretched or weak hip adductors||Stretched or weak hip abductors|
|Distracts IV disc||Compresses IV disc|
|Narrowing of IV foramina|
|Degenerative changes of the hip/spine is more frequent|
|Flexion contractures at hip and knee||Abduction contractures at hip (2)|
|Equinus deformity at the ankle|
Greater than 1½ inches need a prosthetic shoe, and major discrepancy may require surgery.
Accurate measurement of the leg length is essential to provide best possible treatment. The tape measure, standing on blocks, and imaging procedures are commonly used to measure the leg length symmetry. All of these methods are not error-free due to various reasons such as positioning of the patient, differences in leg circumferences, angular deformities, contractures, difficulty palpating bony
prominences, rater reliability, and bias.
Tape measure is used to measure functional shortening. Researchers recommend calculating averages of two tape measurements (direct) to increase validity and reliability.
Direct – A tape measure is used to measure the length from anterior superior iliac spine to medial malleolus.
Apparent – A tape measurement from umbilicus to medial malleolus.
The investigator palpates the posterior superior iliac spines with the patient in a standing position. Then, add 1/16 inch of calibrated blocks under the short leg until the spines are level. However, we use this method typically for measuring anatomical limb length discrepancies.
Various professionals in the medical field used the following methods for measuring leg length discrepancy, but these methods need more research to support their use and effects.