Leg Length Discrepancy
Samedy Srors, CPO, P&O Lecturer
Real different in skeletal length
Measured from ASIS to MM
True Leg Length Discrepancy
Apparent Leg Length Discrepancy
Different in appearance of the legs, whereby one leg looks longer or shorter than another.
Measured from Umbilicus to MM
No fixed deformities of the hip, knee and spine
Patient lies supine.
Pelvis level and legs in line with trunk
Right SideT = 85 cmA = 90 cm
Left SideT = 82 cmA = 87 cm
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 87 cm = 3 cm
•The pelvis tilts to short side, and •The spine must curve to compensate.
When sitting, curved spine
disappears!
3cm block under neath left leg
Level pelvis
Straight spine
Patient lies supine.
If no hip contractor, easy to get legs in line with body.
Pelvis remains tilted and spine curved.
Right SideT = 85 cmA = 90 cm
Right SideT = 82 cmA = 85 cm
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 85 cm = 5 cm
Patient in standing.
Spine deviating to short leg
Scoliosis not allow compensation.
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 85 cm = 5 cm
Patient cannot stand
this way!
3 cm block raised
Pelvis level
Trunk still deviates to short side.
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 85 cm = 5 cm
Patient may be
uncomfortable or not
able to stand this way!
5 cm raised block
Trunk upright
Pelvis not level
Spine not straight
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 85 cm = 5 cm
Patient stands
comfortably
Patient lies supine.
Leg is slightly abducted.
Straight spine
Patient lies supine.
Legs in line with body but spine curves.
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 88 cm = 2 cm
3 cm raised
Straight spine
Pelvis level
But leg abducted
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 88 cm = 2 cm
3 cm raised block
Legs in line with body, but tilt pelvis
Unaffected leg appears short
Build-ups is too big
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 88 cm = 2 cm
2 cm raised block
Legs in line with body but pelvis tilts
Curved spine
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 88 cm = 2 cm
Patient can stand
comfortably with both feet on the
ground
Lie the patient in supine.
Get the legs in line with body.
Try to get the pelvis level, but do not allow leg abducted or adducted.
Measure from umbilicus to bottom of the heel.
This produced apparent leg length discrepancy
What shall we do?
USE THIS MEASUREMENT FOR BUILD UP!
Patient lying supine
Leg slightly adducted.
Leg in line with body
Tilted pelvis
Curved spine
Right SideT = 85 cmA = 90 cm
Left SideT = 82 cmA = 85 cm
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 85 cm = 5 cm
3 cm raised block
Straight spine and level pelvis
Slightly adducted leg
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 85 cm = 5 cm
Patient cannot stand
this way!
Legs in line with body
Tilted pelvis
Curved spine
Build-up not enough
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 85 cm = 5 cm
5 cm raised block
Leg in line with body
Tilted pelvis
Curved spine
Both feet on the ground
Difference
T = 85 cm - 82 cm = 3 cm
A = 90 cm - 85 cm = 5 cm
Patient can stand
comfortably with both feet on the
ground
Lie the patient in supine.
Get the legs in line with body.
Try to get the pelvis level, but do not allow leg abducted or adducted.
Measure from umbilicus to bottom of the heel.
This produced apparent leg length discrepancy
What shall we do?
USE THIS MEASUREMENT FOR BUILD UP!
Patient lying supine
One leg is abducted
Legs in line with body
Curved spine
Tilted pelvis
Right SideT = 85 cmA = 90 cm
Left SideT = 84 cmA = 92 cm
DifferenceT = 85 cm - 84 cm = 1 cm (left side is
short)A = 92 cm - 90 cm = 2 cm (left side is
long)
2 cm raised block (unaffected side)
Leg in line with body
Tilted pelvis
Curved spine
DifferenceT = 85 cm - 84 cm = 1 cm (left side is
short)A = 92 cm - 90 cm = 2 cm (left side is
long)
True LLD is real shortening of the skeleton.
Apparent LLD is how a patient actually stands.
Buildups should always be done following apparent LLD.
Using pelvis to measure leg length in standing can only be done if no fixed contracture or scoliosis exist.
Q & A