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Leg Length Discrepancy and Shoe Raises

In this article

  1. Introduction
  2. Types of Leg Shortening - True Shortening
  3. Types of Leg Shortening - Apparent Shortening
  4. How to Measure a Leg Length Discrepancy
  5. Block Test and Pelvic Landmarks
  6. Tape Measure Method
  7. Do you Adapt Footwear with Raises?
  8. Do you provide assessments for Shoe Raises?


Buchanan Orthotics undertake all types of footwear adaptations for both the NHS and individuals.  Our Orthopaedic technicians based at our head office on Helen Street, Glasgow, have a wealth of experience in adapting both shop-bought and orthopaedic footwear.

Types of Leg Shortening - True Shortening

A True shortening means that there is a physical bony shortening of the bones of the leg and can have a number of causes. .

  • Congenital Causes: Some individuals are born with a slight difference in leg length. In most cases, this difference is minimal and doesn't cause any significant problems.
  • Fractures: In children, if a fracture occurs in the growth plate before it has fused, it can lead to stunted bone growth, resulting in a leg length discrepancy. Fractures in the thigh or shin bones can cause this type of shortening. In adults, a fracture in the neck of the femur (thigh bone) or complex trauma to the leg can also lead to true leg length discrepancy.
  • Surgical Procedures: Following hip replacement surgery, it is not uncommon for individuals to experience a leg length discrepancy. In some cases, the operated side may become shorter, Occasionally, the operated side may become longer, requiring a raise on the contralateral side.
  • Polio: Individuals who have contracted polio may experience a significant difference in leg length. The poliovirus can damage the nerves that control muscle function, leading to muscle weakness and atrophy. As a result, one leg may become shorter and weaker than the other

Types of Leg Shortening - Apparent Shortening

Apparent leg length discrepancy occurs when the legs appear to be of different lengths, despite being physically the same length. The most common causes of apparent leg length discrepancy include:

  • Pelvic Obliquity: An uneven alignment of the pelvis can make one leg appear shorter than the other. This can be caused by various factors, such as muscular imbalances, and pelvic tilt.
  • Scoliosis: Scoliosis can cause both spinal and pelvic imbalances, leading to apparent leg length discrepancy. As the spine curves, it can tilt the pelvis, making one leg appear shorter.
  • Other Factors: Other conditions that can contribute to apparent leg length discrepancy include muscle imbalances, joint contractures, or postural abnormalities.

How to Measure a Leg Length Discrepancy

When it comes to assessing leg length discrepancy, there are various methods to measure and determine the extent of the difference. While imaging techniques such as long-leg X-rays provide the most accurate measurements, they are only sometimes feasible or readily available in all cases. Physical assessment techniques are commonly employed in such situations to measure leg length discrepancy. Orthotists, in particular, utilise two primary methods for this purpose.

Both of these methods below are clinically valid in assessing leg length discrepancy. Orthotists often employ both techniques to ensure accuracy and cross-verify measurements. The choice of method depends on the individual patient and their specific condition.

Block Test and Pelvic Landmarks

In the block test, the orthotist will have the patient stand on blocks of different heights. The orthotist assesses if the patient's hips are level by carefully palpating bony landmarks on the pelvis.This is ususally the ASIS on the anterior side of PSIS posteriorly.  This test aims to determine the height of the raise required to level the hips. This method is advantageous as it is conducted in a weight-bearing position, where leg shortenings are most noticeable. It also gives patients a sense of the raise height they may require.

Tape Measure Method

Another commonly employed method involves using a tape measure to measure the distance between specific bony landmarks on the patient's hips and either ankle bones or the heel. The most commonly used landmarks are the ASIS to the apex of the medial malleolus. It can often be helpful to mark the position on the anke to allow multiple measures to be taken and an average calculated. Measurements are taken for each leg, and the difference between them determines the height of the raise. This method is straightforward and enables quantification of the leg length difference and shows a true leg length difference. 

To measure an apparent shortening the proximal tape position is in the centre of the abdomen and does not move when measuring each leg. 

Do you Adapt Footwear with Raises?

At Buchanan Orthotics, we have a Footwear adaption department where we can add external and internal shoe raises to both shop footwear and orthopaedic footwear. 

Do you provide assessments for Shoe Raises?

Yes, we can provide an assessment at our clinic in Glasgow and Edinburgh

We also have a further guide on our Clinic Website.