Limb Length Discrepancy: How to perform

Last updated on July 6 2022

Description

Limb length discrepancy is the length difference between one leg compared to the other. This problem may be structural, differences in leg length resulting from inequalities in bony structure (e.g. Perthes’ disease) or functional, as a result of altered lower limb biomechanics, unilateral asymmetry of the lower extremity without any concomitant shortening of the osseous components of the lower limb. While a slight difference in leg length may not cause symptoms, a significant difference can cause a noticeable limp and make it difficult for a child to run and play.

Treatment for a discrepancy depends upon the severity. In many cases, a minor difference in leg length can be evened out by wearing a lift in one shoe. A more significant difference may benefit from surgery to make the legs the same length. In most cases, the bones affected by a limb length discrepancy are the femur and tibia. With the limb length discrepancy (LLD) procedure, it is possible to know the distance between the ischial tuberosity edge and lesser trochanters, determining the discrepancy between the right and the left leg.

Measurements

The measurements made by the procedure are displayed in the image: 

• Limb Length Discrepancy (LLD): the difference between the length of both limbs (right and left);
• Right Distance (D): Length of Lesser Trochanters’ Line (LTL) on the right side;
• Left Distance (D): Length of Lesser Trochanters’ Line (LTL) on the left side. 

Auxiliary references 

To show this procedure, PeekMed® needs additional references:

• Hilgenreiner’s line: a horizontal line through the teardrops (or triradiate cartilage in children) of the acetabulum;
• Lesser Trochanters’ Line (LTL): a perpendicular line to the Hilgenreiner’s line, finishing at the medial edge of each lesser trochanter.