Short Leg Syndrome (Unequal Limb Length) Biomechanics

 Unequal limb length is a common condition seen in medical offices. A proper understanding of unequal leg length biomechanics will help the medical practitioner to diagnosis short leg syndrome. A patient may not know that one leg is shorter than the other. They can present with other complaints that lead to this diagnosis. The presence of limb length discrepancy is usually associated with pelvic or lumbar misalignment. The short leg may be FUNCTIONAL, ANATOMICAL, or a COMBO of both.

Studies have found that the majority of patients presenting to our offices are functional, but a growing number seen are anatomical. This is the result of post hip or knee replacement surgeries. Many of these can be corrected with a simple shoe heel lift. You will need an understanding of unequal limb length biomechanics before prescribing a heel lift from Atlas Biomechanics.

FUNCTIONAL SHORT LEG:

1. The sacroiliac joint that is misaligned causing the sacral base to drop to one side.

2. Flexion or Extension with one of the iliac bones out of its normal anatomical position.

3. Posterior Tibial Tendon Dysfunction causing the subtalar joint to overpronate, effectively shorting the leg.

ANATOMICAL SHORT LEG:

1. Hip or knee replacement surgery.

2. Polio.

3. Congenital, birth injuries and infections to the growth plates.

4. Fractures, especially ones at the growth plate.

BIOMECHANICS OF THE SHORT LEG:

1. Supination of the subtalar joint.

2. External rotation of the tibia.

3. External rotation of the knee.

4. Abnormal patella tracking.

5. Pelvic Tilt.

6. Shifting of the center of gravity to the short side.

BIOMECHANICS OF THE LONG LEG:

1. Pronation of the subtalar joint.

2. Internal rotation of the tibia and the knee.

3. Abnormal patella tracking.

4. Vaulting over the hip joint.

GAIT EVALUATION OF THE UNEQUAL LEG LENGTH:

1. Center of gravity shifted to the short side.

2. Unilateral early heel lift.

3. Pelvic Tilt.

4. Shoulder drop.

5. Unilateral subtalar pronation.

6. Unilateral shoe wear (lateral heel).

7. Abnormal knee rotation and patella tracking.

Shoe Heel Lifts manufactured by Atlas Biomechanics come as either EVA/Rubber heel lift or Cork/Rubber blend heel lift.

Heights are 3mm (1/8"), 6mm (1/4"), 9mm (3/8") or 12mm (1/2")

Teri Green

Atlas Biomechanics

About Atlas Biomechanics: We are a woman owned sports medical manufacturer of heel lifts, foot pads and heat mold orthotics.