Leg Length Discrepency

Leg Length Discrepancy Buying Guide

A leg length discrepancy (LLD), also called a leg length difference, occurs when the legs differ in length or alignment. It may be present from birth or develop following injury, surgery or certain degenerative conditions. Small differences are common and do not always cause symptoms.

When a difference is contributing to discomfort or difficulty with walking, a heel lift or shoe raise may be recommended to compensate for the shorter side. The required amount should ideally be based on professional measurement rather than estimated at home, particularly when the difference is substantial or associated with pain.

Our collection includes gel heel lifts, half-length supports and adjustable height inserts that raise the heel or rear of the foot inside suitable footwear.

Which Product is Right for Leg Length Discrepancy?

The best option depends mainly on how much elevation is required, whether additional foot support is wanted and how much space is available inside the shoe.

Heel Lifts

Heel lifts sit beneath the rear of the foot and provide a relatively simple way to add height to one side.

Gel or firm cushioning materials can raise the heel while also absorbing some impact during walking. Their compact design means they occupy less space than a full-length insole and can be moved between compatible pairs of footwear.

Our collection includes dedicated gel heel lifts intended to compensate for leg length differences.

May suit:

• Smaller measured leg length differences
• Targeted elevation beneath the heel
• Shoes with limited forefoot space
• People wanting a compact lift

Supportive Half Insoles

Half-length designs extend beneath both the heel and arch rather than lifting the heel alone.

They may be useful when you want elevation together with additional arch support or heel stability. Because they stop before the toes, they also take up less forefoot space than full-length insoles.

Our collection currently includes half insoles with shaped arch support and contoured heel sections alongside dedicated lifting products.

May suit:

• Heel elevation with additional arch support
• Shoes where a full-length replacement is too bulky
• People wanting a more supportive rear-foot platform

Adjustable and Layered Inserts

Layered designs allow the overall height to be changed by adding or removing sections.

This can make them useful when several elevation settings are available, but the correct height for a true leg length discrepancy should be based on measurement rather than simply choosing the setting that feels tallest or most comfortable.

NHS orthotic guidance notes that professionally supplied heel lifts may use removable layers to achieve a prescribed amount of correction.

Higher settings also require greater shoe depth because raising the heel moves the foot closer to the top and back of the footwear.

What to Consider Before Choosing

Know Which Leg Is Shorter

When lifts are being used specifically for a leg length difference, they are generally intended to compensate for the shorter leg. The amount required can be small, so guessing which side or how much to raise it may create an inappropriate difference rather than correcting one.

If the discrepancy has not been measured, or you are experiencing hip, knee or back symptoms, professional assessment is advisable.

Choose the Correct Height

More elevation is not automatically better.

Heel lifts used clinically can be selected in millimetres according to the measured discrepancy, and some are adjusted gradually using removable layers.

Larger differences may require an external shoe raise or specialist orthotic treatment rather than simply placing a taller insert inside the shoe.

Make Sure Your Shoes Have Enough Room

Raising the heel reduces the amount of space available inside the shoe.

Supportive footwear with a secure fastening, enclosed heel and sufficient depth is preferable. NHS guidance recommends well-fitting shoes with laces, Velcro or buckles and advises against loose styles such as mules or slingbacks when using heel lifts.

Consider Whether You Need Arch Support

A simple heel lift may be enough when the only requirement is additional elevation.

If you also need support beneath the arch or greater stability around the heel, a shaped half insole may be more suitable than a basic wedge.

Benefits of Leg Length Discrepancy Inserts

• Compensate for a Shorter Leg – A correctly selected lift raises the shorter side, helping reduce the difference between the two legs while the product is being worn. Heel lifts and external shoe raises are established non-surgical approaches for accommodating certain leg length discrepancies.
• Support More Balanced Standing and Walking – Reducing an appropriate leg length difference may help the body feel more level during standing and walking. Shoe raises are used clinically to improve balance and accommodate asymmetry where appropriate.
• Fit Discreetly Inside Footwear – Internal heel lifts provide a less visible alternative to an external shoe modification when the required elevation can be accommodated safely inside the shoe.

How to Wear a Heel Lift

1. Position It Securely – Place the lift flat beneath the heel of the appropriate shoe and make sure it cannot slide or tilt during walking. A half insole should sit smoothly beneath both the heel and arch without creating an uncomfortable edge.
2. Check Your Shoe Fit – Once fitted, make sure your heel remains securely contained inside the shoe and that your foot is not being pushed forwards. If the lift causes heel slippage or makes the shoe feel unstable, a deeper or more securely fastened style may be required.
3. Introduce the Lift According to Comfort – A change in elevation alters the position of the foot and leg, so an unfamiliar lift can require an adjustment period. If the product has been prescribed or recommended following assessment, follow the height and wearing instructions provided by your clinician rather than changing the number of layers yourself.
4. Reassess New or Worsening Symptoms – A lift should not create persistent new pain or make walking feel less stable. If discomfort develops in the foot, ankle, knee, hip or back after introducing a lift, stop and have the fit and required elevation reviewed by an appropriate healthcare professional.

Frequently Asked Questions

What is a leg length discrepancy?

A leg length discrepancy happens when one leg is shorter than the other, or the legs are positioned in a way that creates an apparent difference. Causes can include natural development, previous fractures, surgery and certain degenerative conditions.

Do I need a heel lift for a small leg length difference?

Not necessarily. Small differences are common and may cause no symptoms.

A lift is more relevant when a measured discrepancy is contributing to symptoms or when it has been recommended by a podiatrist, physiotherapist, orthotist or other healthcare professional.

How do I know what size heel lift I need?

The required height should ideally be determined by measuring the discrepancy rather than estimating it yourself.

Clinical heel lifts can be prescribed according to measurements in millimetres, and adjustable designs may be used to achieve the required elevation.

Should a heel lift be worn in one shoe or both?

When the purpose is to compensate for a true leg length discrepancy, the lift is generally used to raise the shorter side.

This differs from height-increasing insoles used for cosmetic elevation, which are normally worn at equal heights in both shoes.

Are heel lifts or full-length insoles better?

A heel lift provides compact elevation beneath the rear of the foot and generally requires less shoe space.

A longer or more supportive insole may be preferable when you also need arch support or cushioning across a larger area. Larger corrections may require an external shoe raise rather than either type of internal insert.

When should I seek professional advice?

Professional assessment is advisable if you suspect a leg length discrepancy but have not had it measured, particularly when you experience persistent back, hip, knee or foot discomfort, altered walking or instability.

It is also important to seek advice before attempting to compensate for a substantial difference with a high internal lift.

Learn More About Leg Length Discrepancy and Heel Lifts

For further information about heel elevation and choosing suitable inserts, explore our related guides:

• Are Heel Lifts Good for You?
• Do Height-Increasing Inserts and Insoles Work?
• What Is the Difference Between Insoles and Inserts?