Leg Length Discrepancy

Up to 50% of the population have leg length discrepancy (LLD) of at least 5 mm.1 With leg length discrepancy being so common one might conclude that in most cases the human skeleton would have sufficient tolerance to adapt.  Research into LLD and its association with knee, hip and back pain appears to challenge this commonly held assumption.

Let us review some of the research into LLD and pain syndromes:

  • A comprehensive research review found an association between LLD and low back pain, scoliosis, and osteoarthritis of the hip and knee. 2
  • Patients who were undergoing hip surgery were found to have average LLD of 7.5 mm.  Hip surgery was on the long leg side in 84% of cases.3
  • Patients with mild LLD of 5 mm or greater were assessed for hip and spinal degeneration. A strong correlation was found for increased hip degeneration and lower spine degeneration, more often on the long leg side.4
  • Knee osteoarthritis was observed to be more common on the short leg size in those with LLD. 5
  • 88% of patients with back pain reported relief with a shoe lift intervention.2

Quality of the research

There have been relatively few high quality trials, however a recent randomized controlled trial (considered the most unbiased and accurate type of research) found that in a large group of meat workers, 67% of workers with lower back pain and sciatica improved when their short leg was treated with a shoe lift.

What causes LLD?

Do I need a shoe lift?

If you suffer back pain, especially persistent or episodic back pain, a short leg may be a contributing factor to your pain.  Cameron has also observed the following features related to leg length discrepancy:

  • Persistent or spasmodic low back pain often locates to one side rather than in the middle(central).
  • Pelvic pain (sacroiliac joints) and pelvic torsion (twisting) especially in females.
  • Persistent hip or knee pain (more to one side).
  • Persistent or spasmodic mid-back pain and stiffness which may radiate to the ribs and chest.
  • A lower tolerance for standing still for extended periods.  Weight is frequently shifted from one hip to another. Compensations include flexing one knee or throwing the hip or foot out to the side.
  • Back pain is sometimes spasmodic and severe and out of proportion with the trigger.  Often there appears to be no cause.
  • Employment which requires significant periods of standing and walking increases back pain.
  • Weight gain or obesity can increase (or trigger) leg length related pain.
  • Athletes (and those who maintain very good fitness) tend to experience less pain due to a short leg, but are susceptible to pain when fitness levels are lost.

Interesting Facts

Have you noticed that Usain Bolt has an unusual running style? In fact, his right leg is 13 mm shorter.  Running analysis shows he spends 14% longer on his left leg (long leg side) and strikes the ground with 14% more force on his short leg.  In Usain's autobiography he reports that his short leg is due to scoliosis, however it would seem more likely that his short leg gave rise to his scoliosis (during his growing years).  For more on scoliosis please visit our webpage blog.

Question: Based on the evidence above, in which hip will Usain Bolt more likely have trouble in the future?? If you answered his left, well done! Research shows he may also develop more back pain on this side.

Given the potential for leg length discrepancy to cause pain in adults, it is the authors opinion that every effort should be made to address leg length discrepancy in children and adolescents to help minimize the negative effects on normal spinal development.

So if you have been prescribed a heel lift

Stay tuned because in our next Newsletter we will answer that question and give you many other tips so you can get the maximum benefits from your heel lift.


Knutson GA. Anatomic and functional leg-length inequality: a review and recommendation for clinical decision-making. Part I, anatomic leg-length inequality: prevalence, magnitude, effects and clinical significance. Chiropr Osteopat. 2005;13:11.

Tallroth K, Ylikoski M, Lamminen H, et al. Preoperative leg-length inequality and hip osteoarthrosis: a radiographic study of 100 consecutive arthroplasty patients. Skeletal Radiol. 2005;34:136–139.

Murray KJ, Molyneux T, Le Grande MR, et al. Association of mild leg length discrepancy and degenerative changes in the hip joint and lumbar spine. J Manipulative Physiol Ther. 2017;40:320–329.

Harvey WF, Yang M, Cooke TD, et al. Association of leg-length inequality with knee osteoarthritis: a cohort study. Ann Intern Med. 2010;152:287–295