Leg Length Discrepancy

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Written by: Dr Jeremy Steinberg – created: 15 April 2022; last modified: 24 April 2022

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Leg Length Discrepancy
Epidemiology 59% having an LLD of at least 5mm.
Validity Controversial relation to pain
Treatment Shoe lifts, surgery

Leg length discrepancy also known as leg length inequality refers to unequal lower limb lengths. It may a factor for pain in hip osteoarthritis, knee osteoarthritis, and chronic low back pain.

Aetiology

Anatomic: This refers to LLD due to fracture, trauma or tumour of the growth plate, degenerative disorders, post arthroplasty, Legg-Calvé-Perthes disease, arteriovenous fistula, vascular tumours, post hip arthroplasty.

Developmental: From congenital aplasia, hypoplasia, developmental dysplasia of the hip, clubfoot, hemihypertrophy syndromes, clubfoot

Function: This refers to joint contracture, soft tissue shortening, ligamentous laxity, axial malalignment, and abnormal foot mechanics.

Environmental: repeated exposure to uneven ground such as repeated running on a cambered road.

Biomechanics

The biomechanics were reviewed and assessed by Kakushima et al. They found that there was an asymmetrical lateral bending motion during heel-raising gait as compensation for the LLD.[1]

Classification

  • Mild: <30mm
  • Moderate: 30-60mm
  • Severe: >60mm

Epidemiology

LLD is present in up to 90% of the population, with 59% having an LLD of at least 5mm.

Clinical Features

LLD may be a source of pain and disability.[2] Knee and hip osteoarthritis may develop in the longer limb.

Examine from behind looking at the levels of the PSIS, inferior gluteal folds, and popliteal creases. Each anatomic landmark should be at approximately the same level. If a LLD exists then one hip usually appears lower than the other. There may be a compensatory scoliosis or pelvic obliquity. A compensatory scoliosis usually disappears when the LLD is corrected by placing a block under the shorter leg.

If there is an asymmetry then take careful leg length measurements. One method involves placing the patient supine, making sure the pelvis is level, then measuring from the ASIS to the medial malleolus with the tape running medial to the patella. If the pelvis isn't level then there can be an artificial LLD.

Treatment

There is low quality evidence that shoe lifts reduce pain and improve function in patients with LLD and associated painful musculoskeletal conditions.[3] The percentage correction varies between studies. Trailing 50% correction may be a good starting point.

Surgery can be considered if the discrepancy is over 25mm.

Resources

References

  1. Needham, R.; Chockalingam, N.; Dunning, D.; Healy, A.; Ahmed, E. B.; Ward, A. (2012). "The effect of leg length discrepancy on pelvis and spine kinematics during gait". Studies in Health Technology and Informatics. 176: 104–107. ISSN 0926-9630. PMID 22744469.
  2. Gurney, Burke (2002-04). "Leg length discrepancy". Gait & Posture. 15 (2): 195–206. doi:10.1016/s0966-6362(01)00148-5. ISSN 0966-6362. PMID 11869914. Check date values in: |date= (help)
  3. Campbell, T. Mark; Ghaedi, Bahareh Bahram; Tanjong Ghogomu, Elizabeth; Welch, Vivian (2018-05). "Shoe Lifts for Leg Length Discrepancy in Adults With Common Painful Musculoskeletal Conditions: A Systematic Review of the Literature". Archives of Physical Medicine and Rehabilitation. 99 (5): 981–993.e2. doi:10.1016/j.apmr.2017.10.027. ISSN 1532-821X. PMID 29229292. Check date values in: |date= (help)

Literature Review