Leg Length Discrepancy
A review of the literature
The Long Leg Side (LLS)
Usually left side
Drooping shoulder with elevation of Iliac Crest (Hip).
Decrease Sacral Angle and increase scoliosis:
- As the pelvis moves away from balance and symmetry, it creates changes upwards via the spine (which is attached to the pelvis).
Pelvic obliquity – an upward tilt on coronal plane:
- The hip appears to hike or lift upwards on the same side as the longer limb.
Hip pain – longer leg more likely.
Increase pressure due to decrease contact of femoral head with acetabulum. The greater the LLD the decrease in contact area:
- The hip-joint is basically a ‘ball’ like end of the thigh bone (Femoral head) sitting within a cup like bowl (Acetabulum of the pelvis). If the leg doesn’t rest properly within the Acetabulum, then undue pressure and strain is placed within the joint.
- Deep abdominal muscle grouping that plays an important role in supporting our posture.
- This may lead to possible sciatic problems.
Posterior rotation of Innominate (left side of pelvis) can shorten limb:
- In trying to shorten the longer leg, the pelvis may try to tuck under or tip back.
The Quadricep muscle group is more likely to be active:
- The muscles in the front of the thigh may be working more. The longest of these is the Rectus Femoris which interestingly is a hip flexor, just as is the Psoas muscle.
Hip and knee flexion in sagittal plane:
- The hip and knee may bend slightly in trying to lessen the difference in length between the two legs and so balance the pelvis.
Knee flexion puts strain on knee extensor mechanism:
- By constantly trying to bend the knee, the muscles on the back of the leg may begin to strain as they are constantly placed in a shortened state
The greater the Leg Length Discrepancy the greater the knee flexion:
- The longer the difference in leg length the more obvious the knee bending will be.
Medial knee-joint degeneration:
- Because the Leg Length Discrepancy makes the pelvis move from left to right, undue strain and wear will be felt on the inside line of the knee.
Dorsiflexion at Ankle (foot and toes pointing up):
- Just as the hip and knee bend to decrease the length of the longer leg, the ankle will also do the same. This may also be a natural result of the hip and knee bending
Pronation of foot:
- The foot may flatten out more that the opposing leg, creating a lower inner arch.
May try – Pelvis may correct obliquely by tilting away from long leg side:
- In trying to correct the imbalance, the pelvis may move away from the longer leg side.
Short Leg Side (SLS)
Usually right side
Lumbar convex to short side with subsequent axial rotation:
- The spine usually pushes out to the right, and rotates towards the same side.
Anterior innominate can lengthen limb:
- Often the right side of the pelvis will try to roll forward in trying to increase the length of the short limb, attempting to recreate balance and symmetry.
Hip and knee extension:
- The leg will exaggerate straightening out, to the point where it will appear slightly behind the left when seen from the side view
Lateral knee-joint degeneration:
- Because the pelvis may shift across to the side of the shorter limb, poor function and undue forces may be placed on the outer aspect of the knee-joint.
Plantar flexion of foot / ankle:
- The foot follows the hip and knee extension backwards.
Supination of foot:
- The arch of the foot increases.
Early heel rise:
- Because the lower extremity all the way to the pelvis is trying to extend its length, when walking, the heel will lift off the ground earlier than it would in a balanced body.
May try: Anterior innominate to lengthen short side:
- In an attempt to bring symmetry between the two (2) legs, the pelvis may try to rotate too far forward.
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.