Limb length discrepancy shouldn’t rob you of the ability to walk at the same level. It is possible to avoid walking with a limp or a tilt in the pelvis by using a shoe lift. Limb length discrepancy is thought to lead to stress and strain in the joints of the lower limbs and spine deranging the normal biomechanics hence leading to pain like low back pain
What is limb length discrepancy(LLD)?
Limb length discrepancy simply means having one leg/ limb shorter than the other. LLD can arise from a problem in any of the following regions; spine, pelvis, femur, tibia or foot.
Causes of Limb length discrepancy
Limb length discrepancy can follow a structural or anatomical problem or can follow a functional issue.
Anatomical problems can include
- A fracture that leads to bone loss
- Growth arrest in childhood, preventing one bone from growing to its potential length
- Infection in bone
- Cancer in bone or surrounding muscles
Functional problems can be;
- Weakness in the muscles of the lower limbs following a stroke or injury to nerves in the legs.
Do you need to see a paediatric orthopaedic surgeon?
How to determine LLD
Assessment of length is determined by a doctor. This can be done in two ways;
- Measuring with coleman blocks.
Coleman blocks are premeasured wooden blocks that are placed underneath the shorter leg while you are in a standing position. Blocks of varying heights are placed under the foot until you start to “balanced” and the pelvic tilt disappears.
- Measuring with a tape measure.
Using different bony anatomical landmarks, a tape measure is used to compare the length of the limbs.
After this assessment, this measure is what the orthotist uses to decide how much to add to the heel of each of your shoes.
Indications for a shoe lift
This is indicated for discrepancies 2cm to less than 5cm
A shoe raise is indicated for a limb length less than 5cm. Beyond that, the shoe starts to feel uncomfortable
Benefits of using shoe lifts
- The most obvious advantage is that you get to walk without a limp
- Secondary to that is, their use has been associated with a marked reduction in lower back pain.
Types of shoe lifts commonly used
- Heel lifts
Heel lifts only lift up the back of the foot. These have been noted to lead to Achilles tendon shortening and increased lumbar lordosis. You can achieve a lift of up-to 2cm with these.
- Shoe inserts
This orthosis spans the entire extent of the shoe. It is inserted on the inside and will not be noticed by other people. It however may not be feasible with open shoes and sandals.
- Sole lift
In this case, a couple of layers are added to the entire sole of the shoe. This can be well tolerated up to 5cm of extra height.
Bottom line
Shoe lifts are a conservative means of treatment for limb length discrepancy. They work best for deficits of less than 5cm. They can be in the form of heel lifts, shoe inserts, or sole lifts.
