Can shoe lifts for leg length discrepancy be built into shoes?

Shoe Lifts for Leg Length Discrepancy: Built-In vs External Options

Yes, shoe lifts for leg length discrepancy can be built directly into shoes through various construction methods, and this is often the preferred approach for discrepancies up to 3 cm, offering better aesthetics and function than external lifts.

Construction Methods for Built-In Shoe Lifts

Internal Shoe Modifications (Up to 3 cm discrepancy)

Built-in lifts can be incorporated through specialized shoe construction techniques that integrate the height correction directly into the shoe structure 1. The primary methods include:

• Cork sole incorporation: A 5-10 mm thick cork sole can be built into the shoe construction 1
• Elevated heel construction: The heel height can be increased during manufacturing 1
• Custom-made shoes: Unique, handmade shoes built on a positive model of the patient's foot can incorporate height correction while accommodating deformity 2
• "Shoe within a shoe" design: Modern orthopedic footwear uses fiberglass-reinforced synthetic resin or thermoplast stabilizing components with leather next to the skin, creating aesthetically acceptable designs that are approximately 25% lighter than conventional orthopedic boots 1

Advantages of Built-In Lifts

Built-in shoe modifications provide superior cosmetic appearance and patient acceptance compared to external lifts 3, 1. Key benefits include:

• Better aesthetic acceptance, addressing the cosmetic concerns that make external shoe lifts often unacceptable to patients 3
• Improved stability through integrated construction 1
• Enhanced ventilation through modern materials allowing perforations and open-toe designs 1
• Reduced weight compared to traditional orthopedic boots 1

Clinical Considerations for Height Correction

Magnitude of Discrepancy

The amount of leg length discrepancy determines the appropriate correction strategy:

• Up to 2 cm in adults: Generally tolerable without treatment 3
• 2-3 cm: Ideal range for built-in shoe modifications 1
• Greater than 3 cm: May require external lifts or consideration of surgical options 3
• During growth period: Even discrepancies greater than 1 cm should be treated conservatively to prevent compensatory lumbar scoliosis 3

Balance and Gait Implications

Uncompensated leg length discrepancy from orthotic devices leads to significant biomechanical problems 4. When one foot requires an elevated sole (such as for offloading in diabetic foot ulcers):

• Asymmetrical joint movements occur in feet, knees, hips, and lower back 4
• Higher loads develop in these joints during gait 4
• A contralateral shoe lift should be used to improve comfort and balance 2, 5
• The International Working Group on the Diabetic Foot recommends considering a shoe lift on the opposite limb when using knee-high or ankle-high offloading devices 2

Evidence for Clinical Outcomes

Low-quality evidence suggests shoe lifts effectively reduce pain and improve function 6. In non-randomized studies:

• 88% ± 3% of 349 participants experienced partial or complete pain relief (effect size range 66.7%-100%) 6
• All 22 participants in one RCT experienced pain relief (mean reduction 27 ± 9 mm on 150-mm visual analog scale) 6
• After 12 weeks of wearing customized 3D-printed orthotic insoles with height correction, patients showed relief of joint and lower back pain, with improved stride frequency, stride length, and pace 7

Important Caveats

Be aware that acquired limb-length discrepancy from orthotic devices can lead to musculoskeletal knee or hip complaints 8. Therefore:

• Regular follow-up is essential to assess intervention effectiveness and monitor for secondary complications 8
• Physical therapy should address compensatory mechanisms 8
• While contralateral shoe lifts improve gait asymmetry caused by functional leg length discrepancy, they may not entirely compensate for all abnormal patterns 4