Functional Short Leg and Heel Lifts

A functional short leg (FSL) is a common type of leg-length inequality is a result of rotational patterns of the pelvis and hips. It can also be affected by misalignments or torsional movement in the knee, ankles, and feet.

Limb Length Discrepancy and Heel Lifts

In many cases of a functional short leg, as evidenced by radiographic study, the use of heel lifts has been shown to help eliminate musculoskeletal deficiencies and improve patient outcomes. Providing support for the short limb with a heel lift is important when recognizing the functional short leg because providing a lift will likely diminish the associated sacroiliac subluxations.

Look at and palpate the iliac crests and the greater trochanters to see if they are of unequal height. Finally, look and palpate the lumbar spine. A typical postural distortion for a short leg will create lumbar scoliosis whose convexity moves toward the side of the FSL.

After you have measured your patient’s actual leg-length discrepancy, it is always safe to under correct. The classic rule of thumb is to cut the LLI in half and then start with the appropriate-sized heel lift.

Proceed to a 3 mm (1/8") heel lift and have the patient wear this for two weeks. Then re-evaluate.
Proceed to a 6 mm (1/4") heel lift or 9 mm (3/8") heel lift only if necessary. Use the two-week break-in period as indicated above. Then re-evaluate.

From a practical standpoint, it is very important to be able to confidently determine if someone truly has a short leg due to anatomy or functionality and to use a heel lift if need be.

Teri Green

Atlas Biomechanics