24: Limb Length Discrepancies - Smith Flashcards Preview

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Flashcards in 24: Limb Length Discrepancies - Smith Deck (16)

what is a significant LLD?

3mm - 22mm

the numerical value is not as important, significant means it causes symptoms


structural v. functional LLD

structural - anatomical shortening [polio, physeal damage, congenital dysplasia, post surg]

functional - due to biomechanics [excessive STJ pronation/greater than 3 degree eversion* when compared to contralateral limb, joint contracture, axial malalignment, shoegear induced]

could also be a combination


pelvis tilts downward on ____ side


this is a structural LLD compensation


scoliosis with convex side over _______ limb

(reducible with NWB - can become rigid)

this is a structural LLD compensation


symptoms association with LLD

- asymptomatic
- pain with standing and WB
- sacroiliac jt pain due to pelvic tilt [pelvic tilt syndrome]
- lateral knee pain on short limb, medial knee pain on long limb
- low back pain due to disc protrusion with scoliosis


pronate on long side, supinate on short side

structural LLD


knee pain laterally on one knee and medial on the other indicates ...

lateral on short limb
medial on long limb


pronation is ...

compensation for structural LLD or a cause of a functional LLD


how to do a direct clinical measurement?

ASIS to medial malleolus (could also be ASIS to lateral malleolus or umbilicus to medial malleolus)

watch out - obese pts, jt contracture not accounted for, torsion of bones not accounted for, pelvic torsion not accounted for


pt has WB LLD, but does not have NWB

probably functional


how to do an indirect LLD check?

- WB with foot in resting calcaneal stance position
- Pelvic landmarks palpated, keeping hands parallel
- ASIS and PSIS located
- Blocks of a known thickness placed under short side until landmarks are at same level

- Pelvic height difference not accounted for
- Third reference point added for accuracy
[Greater Trochanter - If this measurement is equal then the LLD occurs within pelvis]


pelvic compensation (long v short limb)

Posterior pelvic rotation with pronation on long limb

Anterior pelvic rotation with supination on short limb


most common compensation

functional scoliosis

Must determine if scoliosis is functional and a result of a LLD or if is the primary pathology and the LLD is a compensation for the scoliosis


fixed scoliosis

does not reduce with NWB


If functional caused by increased pronation, must correct with ...


If structural then a lift is used
If combined, then an orthotic with a lift


how do you use a lift?

If discrepancy 1 cm or more, a full length lift is used to prevent equinus

Increase in increments of 3mm (1/8”) per week

Can get 8 mm of lift in a normal shoe

If greater than 8 mm needed, apply 50% of lift to shoe of short side and acquire other 50% by deepening shoe on long side

Decks in Surg+BioMech [all exams] Class (68):