Leg Length Discrepancy
| 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, chronic low back pain, and even headaches.
It can be structural (true bony length difference) or functional (legs equal in length but appearing unequal due to pelvic tilt, spinal curvature, or muscle imbalances)
Aetiology
Anatomic: This refers to LLD due to fracture, trauma or tumour of the growth plate, degenerative disorders, post arthroplasty, Legg-CalvƩ-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][2]
Even relatively small discrepancies (5ā10 mm) can alter biomechanics and require compensatory adjustments in posture and gait. The body will typically tilt the pelvis down on the shorter side, leading the lumbar spine to bend toward the longer leg to keep the shoulders and head level . This compensatory pelvic obliquity and lumbar curvature (a form of functional scoliosis) can propagate up the kinetic chain. Over time, these adaptations may strain muscles and joints asymmetrically and have far-reaching effects beyond the lower limbs.
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.[3] 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.[4] 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.
Heel Lifts: For structural LLD, adding a lift to the shoe of the shorter leg is a simple way to level the pelvis.
Custom Foot Orthotics: Orthotic insoles can correct foot malalignments (like overpronation or arch collapse) that contribute to functional LLD or general postural instability. If an orthotic corrects foot alignment but does not account for a true leg-length discrepancy, it might inadvertently worsen cervical tension because of the loss of adaptation. For example the longer leg may develop a compensatory pes planus to functionally shorten the leg, if you correct the foot arch alone without also raising the shorter contralateral leg the patient may feel worse.
Resources
References
- ā Kakushima, Mototaka; Miyamoto, Kei; Shimizu, Katsuji (2003-11). "The Effect of Leg Length Discrepancy on Spinal Motion During Gait: Three-Dimensional Analysis in Healthy Volunteers". Spine (in English). 28 (21): 2472ā2476. doi:10.1097/01.BRS.0000090829.82231.4A. ISSN 0362-2436. Check date values in:
|date=(help) - ā 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: 104ā107. ISSN 0926-9630. PMID 22744469.
- ā Gurney, Burke (2002-04). "Leg length discrepancy". Gait & Posture. 15 (2): 195ā206. doi:10.1016/s0966-6362(01)00148-5. ISSN 0966-6362. PMID 11869914. Check date values in:
|date=(help) - ā 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): 981ā993.e2. doi:10.1016/j.apmr.2017.10.027. ISSN 1532-821X. PMID 29229292. Check date values in:
|date=(help)
Literature Review
Literature Review
- Reviews from the last 7 years: review articles, free review articles, systematic reviews, meta-analyses, NCBI Bookshelf
- Articles from all years: PubMed search, Google Scholar search.
- TRIP Database: clinical publications about evidence-based medicine.
- Other Wikis: Radiopaedia, Wikipedia Search, Wikipedia I Feel Lucky, Orthobullets,
