Leg Length Discrepancy – LLD
The body is a mechanism that works tirelessly in its attempt to bring balance and equilibrium to all its functions. This process is clearly seen when addressing issues of Leg Length Discrepancy (LLD). In the case of LLD, the body’s attempt to improve the situation may lead to greater inconsistencies and tendencies towards dis-ease, rather than ease.
LLD is a state in which one leg is different in length to the other. Research is split on how prevalent this, with statistics ranging from 40% to 70% of the population.
What is the difference between structural and functional LLD?
This can be broken down into Structural (True) LLD or Functional LLD. Structural LLD is when there is an actual difference in the length of the femur (thigh bone) and/ or tibia (larger bone of the lower leg) on either side. Functional LLD on the other hand is an change in the relationship of the parts of one leg relative to the other.
Research differs on how much LLD is necessary for it to become a health related concern.
Some suggest only a few mm difference can create lower back pain, while others propose that at least 30 – 40 mm is necessary. One thing is clear however; LLD will alter the way your body moves. Whether the change is minor or glaringly obvious, changes in mechanics will be occurring. For most of us this will eventuate into nothing more than the occasional ‘niggle’ or ‘twinge’, for others it may be that lower back pain that no amount of rubbing or cracking can fix.
We are the sum of all our parts that influence, and are influenced by its neighbour and as an extension, its neighbours neighbour.
Think of the body in terms of being like a building or man-made vertical structure. One element these all have in common is a stable base of support; a secure foundation from which they can build upwards. The human body is no different. Our relationship to the ground via our feet and lower legs provides a way in which we can support all the elements above – hips, spine, torso, shoulders, neck, and head.
What can cause functional LLD?
So how can we come to this situation? What can create LLD and an eventual change in how we stand, sit, and walk?
Changes can occur from – Joint considerations that may lead to changes within the spine or leg:
- Dropped arch of the foot
- Rigid and high arch of the foot
- Tightness in one hip relative to the other that may lead to the pelvis favouring movement in one direction
- Weakness across a joint – for example, back of the knee creating hyper-extension of the lower leg.
What can go wrong if I have Functional LLD?
- Poor postural patterns – imbalance in the feet, legs, and pelvis can create changes all the way through the spine, rib cage, shoulders, neck, and head.
- Lower Back Pain – the most common condition associated with LLD
- Misalignment and/or rotation of the pelvis. What does the pelvis look like?
- Severe hip pain – often seen on the longer leg side. Research has explored how the greater the LLD the greater the pressure found in the hip joint along a smaller surface area. That means that load is being supported within a concentrated area – leading to greater wear and tear.
- Myofascial (fascia) restriction and associated pain. What is fascia?
- Physical performance considerations: when placing the body under extreme load or athletic performance. This can be as little as lifting a heavy wheelbarrow in the garden, or to performing compound weightlifting exercises.
Burke Gurney, B. (2002). Review – Leg length discrepancy. Gait and Posture, 15, 195–206.
Defrin, R., Benyamin, S.B., Dov Aldubi, R, & Pick, C.G. (2005). Conservative Correction of Leg-Length Discrepancies of 10mm or Less for the Relief of Chronic Low Back Pain. Arch Phys Med Rehabil, Vol 86, November, pp. 2075-2080.
Gibbons, P., Dumper, C., & Gosling, C. (2002). Inter-examiner and intra-examiner agreement for assessing simulated leg length inequality using palpation and observation during a standing assessment. Journal of Osteopathic Medicine, 2002; 5(2): 53-58
Hanada, E., Kirby, R.L., & Mitchell, M., Janneke, M., & Swuste, B.S. (2001) Measuring Leg-Length Discrepancy by the “Iliac Crest Palpation and Book Correction” Method: Reliability and Validity. Arch Phys Med Rehabil Vol 82, pp. 938-942.
Knutson, G.A. (2002). Incidence of foot rotation, pelvic crest unleveling, and supine leg length alignment asymmetry and their relationship to self-reported back pain. Journal of Manipulative and Physiological Therapeutics, Volume 25, Number 2, p. 2-7.
Knutson, G.A., & Owens, E. (2005). Erector spinae and quadratus lumborum muscle endurance tests and supine leg-length alignment asymmetry: an observational study.Journal of Manipulative and Physiological Therapeutics. October, 575-580.
Krawiec, C.J., Denegar, C.R., Hertel, J., Salvaterra, G.F., & Buckley, W.E. (2003). Static innominate asymmetry and leg length discrepancy in asymptomatic collegiate athletes. Manual Therapy, 8(4), 207–213.
Raczkowski, J.W., Daniszewska, B., & Zolynski, K. (2010). Functional scoliosis caused by leg length discrepancy. Arch Med Sci, June, 393-398.
Shapiro, F. (2002). Pediatric Orthopedic Deformities: Lower Extremity Length Discrepancies. Gulf Professional Publishing.
Woodfield, H.C., Gerstman, B.B., Olaisen, R.H., & Johnson, D.F. Interexaminer reliability of supine leg checks for discriminating leg-length inequality. Journal of Manipulative and Physiological Therapeutics, Volume 34, Number 4, 239-246.
Young, R.S., Andrew, P.D., & Cummings, G.S (2000). Effect of simulating leg length inequality on pelvic torsion and trunk mobility. Gait and Posture, 11, 217–223.