Functional Leg Length Discrepancy & Heel Lifts

Understanding when heel lifts help asymmetry and hip level differences, and when conservative correction is most effective.

When Heel Lifts Help Functional Leg Length Discrepancy

Heel lifts are most effective when asymmetry causes hip level differences and compensatory movement patterns. They work best for functional discrepancies caused by muscle imbalances, joint restrictions, or postural adaptations. Clinician evaluation is essential to distinguish functional from structural LLD and determine appropriate lift height, typically starting with 3-6mm corrections.

Understanding Leg Length Discrepancy

Functional leg length discrepancy differs from structural (anatomical) discrepancy. While structural LLD involves actual bone length differences, functional LLD results from compensatory patterns, muscle imbalances, or joint restrictions that create apparent length differences.

Functional LLD

  • • Muscle imbalances and tightness
  • • Joint restrictions or contractures
  • • Postural compensations
  • • Pelvic obliquity
  • • Often responds to conservative treatment

Structural LLD

  • • Actual bone length differences
  • • Congenital conditions
  • • Growth disturbances
  • • Fracture malunion
  • • Requires different management approach

Clinical Assessment Guidelines

When Heel Lifts Are Indicated

  • • Hip level differences causing low back pain
  • • Compensatory gait patterns
  • • Functional discrepancies 5-15mm
  • • Asymmetric foot symptoms
  • • Positive response to trial lift

When to Avoid Heel Lifts

  • • Structural LLD >20mm (consider surgical consultation)
  • • Achilles tendon tightness or equinus
  • • Scoliosis as primary cause
  • • Forefoot pressure tolerance issues
  • • Poor balance or stability

Conservative Treatment Approach

Progressive Implementation

Start with 3-6mm lifts and gradually increase over 2-4 weeks. Most functional discrepancies require no more than 12-15mm correction.

Monitor Response

Assess pain reduction, gait symmetry, and functional improvement. Discontinue if symptoms worsen or new problems develop.

Adjunctive Treatments

Combine with physical therapy, stretching, and strengthening to address underlying functional limitations.

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Frequently Asked Questions

When do heel lifts help functional leg length discrepancy?

Heel lifts help when asymmetry causes hip level differences and compensatory movement patterns. They're most effective for functional discrepancies caused by muscle imbalances, joint restrictions, or postural adaptations rather than true anatomical differences.

How much heel lift is safe to use?

Start with 3-6mm lifts and gradually increase. Most functional discrepancies require no more than 12-15mm correction. Excessive lifts can cause Achilles tendon tightness and forefoot pressure issues.

When should heel lifts not be used?

Avoid heel lifts when structural leg length differences exceed 20mm, with Achilles tendon tightness, severe ankle equinus, or when the apparent discrepancy is caused by scoliosis or pelvic rotation rather than leg length difference.

How can I tell if I have functional vs structural leg length discrepancy?

Functional discrepancy often improves with position changes, muscle stretching, or manual therapy. Structural discrepancy remains constant regardless of positioning. Clinical examination by a healthcare provider can determine the difference and appropriate treatment.

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